l-Rhamnulose (6-deoxy-l-arabino-2-hexulose) and l-fuculose (6-deoxy-l-lyxo-2-hexulose) were prepared from l-rhamnose and l-fucose by a two-step strategy. In the first reaction step, isomerization of l-rhamnose to l-rhamnulose, or l-fucose to l-fuculose was combined with a targeted phosphorylatio...
The mesyloxy group of 1-azido-1-deoxy-4-O-mesyl-d-glucitol could be displaced by azide, in the 2,3:5,6-di-O-isopropylidene derivative 4 or the tetraacetate, yielding, after removal of the protecting groups, 1,4-diazido-1,4-dideoxy-d-galactitol (7). The 2,3- (10) and 5,6-O-isopropylidene derivati...
6-Deoxy-6-fluoro-α-d-galactose (1) was converted by conventional methods into crystalline 2,3,4-tri-O-acetyl-6-deoxy-6-fluoro-α-d-galactosyl bromide (2). Treatment of 2 with methanol-silver carbonate gave the methyl β-glycoside and reaction with silver diphenyl phosphate, followed by hydrogen...
Azastene (4,4,17α-trimethylandrost-5-eno [2,3-d]isoxazol-17-ol), when given orally to rats at a dose of 12 mg/kg once on day 10 of pregnancy, induced resorption of all fetuses and a precipitous decline of circulating progesterone levels in all test animals. The disruption of pregnancy was preve...
Azastene is an orally effective “luteolytic” agent in rhesus monkeys. In nonpregnant monkeys it reverses the human chorionic gonadotropin-stimulated increase in progesterone production and delay in the onset of menstruation, and in inseminated monkeys, it prevents pregnancy if given for 5 days...
Azastene, a synthetic steroid of the androstano (2,3-d) isoxazole family, has been shown to terminate pregnancy in the rat and in the primate. Its antifertility effect in the rat is associated with a decrease of progesterone and an increase in prostaglandin F (PGF). Its mechanism of action has b...
A UV irradiation-induced mutant of Bacillus sphaericus 2362 whose sporulation was inhibited neither by natural amino acids nor by l-ethionine was selected. The mutant (A61) grew slowly in rich amino acid medium and contained increased concentrations of heat-resistant spores throughout the growth...
2–4 mM l-ethionine completely inhibits DNA synthesis in phytohaemagglutinin- or concanavalin A-stimulated lymphocytes even though it does not prevent the morphological changes characteristic of blast formation. Evidence is presented which indicates that complete commitment to DNA synthesis as w...
SummaryEffects of N,N′-diphenyl-p-phenylenediamine (DPPD), an antioxidant, on liver carcinogenesis caused by a choline-deficient L-amino acid-defined (CDAA) diet containing ethionine were studied in Fischer 344 rats. Male animals, 6 weeks old, were fed a CDAA diet, a choline-supplemented L-amin...
Phosphorus-31 surface coil spectroscopy has been used to study the effects of l-ethionine administration on the hepatic metabolism of the anesthetized Sprague-Dawley rat. ATP levels were found to decrease by ∼30% 3 to 4 hr after administration of 1 mg/g body wt of l-ethionine to the anesthetize...
The effect of L-ethionine, the ethyl analog of the essential amino acid methionine the SOS system of Escherichia coli was studied. This compound does not induce either inhibition of cell division nor cessation of cell respiration in a RecA+ Met+ RelA+ strain, nor in RecA+ Met− RelA+ or RecA+ Met...
SummaryThe acute, 7-day LD50 in Swiss mice of D-ethionine administered intraperitoneally, was determined as 185 mg/kg with 95% confidence limits of 163 and 210 mg/kg. L-ethionine, the stereoisomer, which is more potent in inhibiting liver RNA synthesis, was not lethal at 2500 mg/kg. This acute t...
The mutagenic effect of l-ethionine in plants was examined using heterozygotic soybean and maize. Seeds were soaked in solutions of different concentration and the mutational frequency increment was measured by the increase of mutant sectors on the leaf. l-ethionine has a mutagenic effect in pla...
Suckling rats were injected subcutaneously with doses of l-ethionine (0.1 μmole/g body wt and 0.5 μmole/g body wt) at intervals of 12 hr. In the latter group, phenylalanine hydroxylase was effectively inhibited in vivo resulting in hyperphenylalaninemia and phenylketonuria. Due to the well-kno...
Summaryd,l-Ethionine produces pancreatic exocrine necrosis and islet proliferation in hamsters and dogs. As a first step in examining whether induction of islet proliferation has therapeutic applications in animals with exhausted or destroyed insulin-producing β-cells, we studied pancreatic pat...
Summaryd,l-Ethionine produces pancreatic exocrine necrosis and islet proliferation in hamsters and dogs. As a first step in examining whether induction of islet proliferation has therapeutic applications in animals with exhausted or destroyed insulin-producing β-cells, we studied pancreatic cel...
The hexahistidine-tagged organophosphorus hydrolase (OPH6His) has been immobilized on a Zr-MOF, namely UiO-66-NH2. The resulting enzyme-MOF composite was used as a carrier to facilitate the hydrolysis of an organophosphate pesticide, i.e., methyl parathion in to p-nitrophenol (PNP). The formatio...
Photochemistry of the herbicide 3,5-dibromo-4-hydroxybenzonitrile (1) (bromoxynil) was extensively investigated using ultraviolet radiation of wavelengths (λ) around 313 nm. Aqueous-phase photoreactions of 7.8 μM of 1 in water in the absence (pH 6.0–7.0 and presence of 5, 10, 15, 20, 40, 45, ...
Treatment with 25 μmol/l d,l-buthionine-S,R-sulphoximine (BSO) for at least 24 h depleted glutathione (GSH) in human non-small cell lung (SW-1573), ovarian (A2780) and breast carcinoma (MCF-7) cell lines to about 20% of control, and was accompanied by a 2-fold potentiation of the cytotoxicity o...
We have examined the toxicity of trans-platinum (trans-diamminedichloroplatinum II) to heme and hemoprotein metabolism in the kidney of glutathione (GSH)-depleted rats and compared it with that produced by cis-platinum. Unlike cis-platinum treatment (7.0 mg/kg, i.v.) which caused after 7 days si...
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