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Pleiotrophin (PTN) is a platelet-derived growth factor-inducible, 18-kDa heparin-binding cytokine that signals diverse phenotypes in normal and deregulated cellular growth and differentiation. To seek the mechanisms of PTN signaling, we studied the interactions of PTN with the receptor protein tyrosine phosphatase (RPTP) beta/zeta in U373-MG cells. Our(More)
Cholera toxin (CT), the most commonly used mucosal adjuvant in experimental animals, is unsuitable for humans because of potent diarrhea-inducing properties. We have constructed two CT-A subunit mutants, e.g., serine-->phenylalanine at position 61 (S61F), and glutamic acid-->lysine at 112 (E112K) by site-directed mutagenesis. Neither mutant CT (mCT), in(More)
Small GTPases of the ADP-ribosylation factor (ARF) family play a key role in membrane trafficking by regulating coated vesicle formation, and guanine nucleotide exchange is essential for the ARF function. Brefeldin A blocks the ARF-triggered coat assembly by inhibiting the guanine nucleotide exchange on ARFs and causes disintegration of the Golgi complex(More)
Staphylococcus aureus produces bi-component leukotoxins composed of non-associated soluble proteins, S and F. Neither S nor F component alone is cytotoxic, but components together are active. These include Panton-Valentine leukocidin (PVL), gamma-hemolysin, LukE-LukD and others. Purification of leukotoxin from Staphylococcus aureus V8 strain (ATCC 27733)(More)
Shiga-like toxin 1 (Stx1), produced by enterohemorrhagic Escherichia coli, binds to its receptor, globotriaosylceramide (Gb3), on target cell membranes, as a prerequisite for inducing host cell intoxication. To examine further toxin-receptor interactions, we established an Stx1-resistant clone of Vero cells by chemical mutagenesis. The mutant cells,(More)
AIM Urinary concentration of oxalate is considered an important factor in the formation of renal stones. Dietary oxalate is a major contributor to urinary oxalate excretion in most individuals. Furthermore, oxalate degrading bacteria have been isolated from human feces. We investigated the significance of oxalate degrading bacteria for urinary oxalate(More)
Subtilase cytotoxin (SubAB), which is produced by certain strains of Shiga-toxigenic Escherichia coli (STEC), cleaves an endoplasmic reticulum (ER) chaperone, BiP/Grp78, leading to induction of ER stress and caspase-dependent apoptosis. SubAB alters the innate immune response. SubAB pretreatment of macrophages inhibited lipopolysaccharide (LPS)-induced(More)
The effects of crude polyphenol extracted from immature apples on the enzymatic and biological activities of a cholera toxin (CT) were investigated. When the apple polyphenol extract (APE) was examined for properties to inhibit CT-catalyzed ADP-ribosylation of agmatine, it was found that APE inhibited it in a dose-dependent manner. The concentration of APE(More)
Staphylococcal alpha-toxin, known for its wide spectrum of biological activities, is involved in the pathogenesis of Staphylococcal infectious diseases. In recent years, various phytochemicals have been found to have antimicrobiological, including antibacterial, antiviral and antifungal, and antitoxic activities. We investigated whether several plant(More)
Resveratrol (3,4',5-trihydroxystilbene), a natural polyphenol found in red grapes, berries and peanuts, exhibits anti-inflammatory, cell-growth modulatory, and anticarcinogenic effects. In this report, we show that resveratrol inhibited cholera toxin (CT)-induced cyclic AMP accumulation in Vero cells. Resveratrol suppressed the CT activity by suppressing(More)