Myelodysplastic syndromes (MDS) are characterized by peripheral blood cytopenias despite hypercellularity of the bone marrow regarded as the result of ineffective hematopoiesis mainly caused by ...apoptosis. In this study, we examined the role of tumor necrosis factor (TNF)-induced apoptosis in the bone marrow cells of MDS patients. The constitutive expression of mRNA for TNF receptors (TNFR), including TNFRI and TNFRII, and the adapter molecules, such as the TNF receptor-associated death domain protein (TRADD), Fas-associated death domain protein (FADD), receptor interacting protein (RIP) and TNF receptor-associated factor 2 (TRAF-2) were analyzed by reverse transcriptase (RT)-PCR in bone marrow samples from control, MDS and AML cases. In bone marrow cells from refractory anemia (RA) patients, there was a significant increase in TNFRI expression as compared with control subjects. The expression of TNFRII was also up-regulated in RA cases. In contrast, RA with excess of blasts (RAEB), RAEB in transformation (RAEB-T) and AML cases revealed increased expression of TNFRII, whereas the expression of TNFRI was comparable to control subjects. Immunohistochemical staining revealed that the TNFRI, as well as TNFRII of MDS bone marrow was expressed mainly in hematopoietic cells, but not in macrophage-lineage stromal cells at the protein level. An increased constitutive expression of mRNA for TRADD, FADD and RIP and decreased expression of mRNA for TRAF-2 were observed in bone marrow cells from MDS patients, especially from RA patients, as compared with controls, although the differences were not significant. In many of the AML bone marrow samples, strong expression of TRAF-2 mRNA was marked, while expression levels of other proteins were similar to those in control subjects. These data suggested enhanced signaling by the TNFRI–TRADD–FADD pathway and suppressed signaling by the TRAF-2 pathway in RA. Thus, TNF-α-induced apoptosis may play a role in ineffective hematopoiesis in “early stage MDS” bone marrow, although the regulatory mechanisms for TNF-α-induced signaling would be complicated and not be simply explained only by these pathways.
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The dihydroxyisoleucine-, thiazoline- and dehydroamino acid-containing pentapeptide of the thiostrepton family of peptide antibiotics was synthesized, which featured the β-lactone opening by ...phenylselenylation, the vinylzinc addition to the chiral sulfinimine, the Wipf oxazoline–thiazoline conversion method and the oxidative
syn-elimination of the phenylseleno group.
Sphingolipid activator proteins (SAPs) are non-enzymatic glycoproteins required for lysosomal degradation of various sphingolipids
with short oligosaccharide chains by their respective exohydrolases. ...Four of these (SAP-A to SAP-D or saposins A to D) are
derived from a common precursor by proteolytic processing. Alternative splicing of the SAP-precursor gene results in insertion
of additional 6 or 9 bases of exon 8â² or 8, respectively, into the SAP-B coding region of the transcribed mRNAs.
To examine the features of the three different SAP-precursor proteins (prosaposins), the respective cDNAs were stably expressed
in baby hamster kidney cells. Pulse-chase experiments with transfected cells and endocytosis studies on human fibroblasts
showed that synthesis, transport, and maturation of all SAP-precursor led to formation of the four mature SAPs (SAP-A to SAP-D).
In order to determine the biological function of the three different SAP-B isoforms, SAP-precursor-deficient human fibroblasts
were loaded with recombinant SAP-precursor proteins with or without 2- and 3-amino acid insertions, respectively, purified
from the medium of the baby hamster kidney cells. They were found to stimulate at nanomolar concentrations the turnover of
biosynthetically labeled ceramide, glucosylceramide, and lactosylceramide. Since the physiological function of SAP-B is to
stimulate the degradation of sulfatide by arylsulfatase A (EC 3.1.6.1) and globotriaosylceramide by β-galactosidase (EC 3.2.1.23)
loading studies with the respective exogenously labeled lipids on SAP-precursor-deficient fibroblasts were performed. Addition
of different purified SAP-precursors to the medium of the lipid-loaded fibroblasts showed positive stimulation of the lipid
degradation by all three SAP-B isoforms derived from the SAP-precursors. These findings establish that all three forms of
the SAP-B can function as sulfatide/globotriaosylceramide activator.
Sorbitol and sucrose are major products of photosynthesis distributed in apple trees (Malus domestica Borkh. cv. "Greensleeves") that affect quality in fruit. Transgenic apple plants were silenced or ...up-regulated for sorbitol-6-phosphate dehydrogenase by using the CaMV35S promoter to define the role of sorbitol distribution in fruit development. Transgenic plants with suppressed sorbitol-6phosphate dehydrogenase compensated by accumulating sucrose and starch in leaves, and morning and midday net carbon assimilation rates were significantly lower. The sorbitol to sucrose ratio in leaves was reduced by ≈90% and in phloem exudates by ≈75%. The fruit accumulated more glucose and less fructose, starch, and malic acid, with no overall differences in weight and firmness. Sorbitol dehydrogenase activity was reduced in silenced fruit, but activities of neutral invertase, vacuolar invertase, cell wall-bound invertase, fructose kinase, and hexokinase were unaffected. Analyses of transcript levels and activity of enzymes involved in carbohydrate metabolism throughout fruit development revealed significant differences in pathways related to sorbitol transport and breakdown. Together, these results suggest that sorbitol distribution plays a key role in fruit carbon metabolism and affects quality attributes such as sugar-acid balance and starch accumulation.
27aEK-4 THz Polarization pulse shaping Sato, M.; Higuchi, T.; Kanda, N. ...
Meeting Abstracts of the Physical Society of Japan,
2013/03/26
Journal Article
Pseudomonas aeruginosa infections are particularly common in people with cystic fibrosis and despite regular treatment with antibiotics, lung damage due to chronic infection with P. aeruginosa ...remains the major cause of death in those patients. In order to initiate an infection, P. aeruginosa needs contact with the respiratory epithelial surface and by means of its adhesins i.e., fimbria, hemagglutinins,etc., it recognizes and adheres to the corresponding epithelial receptors. We treated P. aeruginosa strains isolated from sputum of cystic fibrosis patients with several glycolipids such as sulfatide, sulfated ganglioside mixture (GM1a, GD1b, GT1b), asialo-GM1 and galactocerebrosides to determine their effect on attachment with pharyngeal epithelial cells. Sulfated ganglioside mixture and sulfatide inhibited the attachment of P. aeruginosa significantly, whereas asialo-GM1, Gal-Cer and sodium sulfite had no effect on attachment inhibition. This finding suggests that sulfated glycoconjugates found in the extracellular matrix, in mucus and on the surface of epithelial cells of human trachea and lung mediates attachment of P. aeruginosa.
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