2-Aminoethylphosphonic acid concentrations in some rumen ciliate protozoa.
(17/26)
The concentration of 2-aminoethylphosphonic acid has been measured in seven genera of rumen ciliate protozoa. Expressed as milligrams per gram of total nitrogen, 2-aminoethylphosphonic acid concentrations ranged from 17.2 in Ophryoscolex spp. to 72.4 in Eremoplastron spp. (+info)
The effects of aminoethyl phosphonic acid on hepatic microsomal drug metabolism and ultrastructure of normal and cholesterol fed rats.
(18/26)
The effects of parenteral administration of aminoethyl phosphonic acid (AEP) on the liver microsomal drug metabolism and ultrastructure were studied in normal and 1% cholesterol-fed albino rats. AEP administration to rats fed a stock-diet resulted in decreased demethylation of aminopyrine with a concomitant fall in cytochrome P-450 level. Aniline hydroxylation remained unaltered. AEP injection to cholesterol-fed rats, caused marked reduction in both aminopyrine demethylation and aniline hydroxylation, with a significant increase in cytochrome P-450 level. AEP injection to both control and cholesterol-fed animals produced a modest increase in Bilirubin UDP-glucuronyl transferase. RNA:DNA ratio showed remarkable elevation in rats fed the cholesterol diet with AEP injection. AEP injection caused an atypical smooth endoplasmic reticulum and a marked loss of nuclear euchromatin. Effect of AEP was more pronounced in rats receiving the cholesterol-diet. AEP administration thus induces structural and drug metabolic enzyme alteration in liver. (+info)
The characteristics of peptide uptake in Streptococcus faecalis: studies on the transport of natural peptides and antibacterial phosphonopeptides.
(19/26)
Transport of natural peptides and antibacterial phosphonopeptide analogues was studied in Streptococcus faecalis ATCC 9790. Competition studies, and the isolation of peptide-transport deficient mutants, indicate the presence of two peptide permeases. One is a high-rate system used by dipeptides, and to a lesser extent tripeptides; the other is a low-rate oligopeptide system. Following uptake, peptides are cleaved and their amino acid residues may undergo rapid exodus. Different strains of S. faecalis differ in their rates of peptide transport. (+info)
A novel sphingophosphonoglycolipid containing 3-O-methylgalactose isolated from the skin of the marine gastropod Aplysia kurodai.
(20/26)
A novel sphingophosphonolipid was isolated from the skin of a marine gastropod, Aplysia kurodai. It was composed of one mol each of sphingosine base, fatty acid, glucose, galactosamine, and an unknown sugar and two mol each of galactose and aminophosphonic acid. The unknown sugar was identified as 3-O-methylgalactose by GC-mass spectrometry of the alditol acetate derivative and by GLC of the trimethylsilyl methylglycoside derivative. The aminophosphonic acid was identified as 2-aminoethylphosphonic acid by TLC of the free acid and the dinitrophenyl (DNP-) compound and by GLC of the O-di-trimethylsilyl-N-isothiocyanate compound. Thus, a ceramide bis(2-aminoethylphosphono)-pentaoside structure having an oligosaccharide chain consisting of one mol each of glucose, 3-O-methylgalactose and galactosamine and two mol of galactose was proposed. (+info)
Molecular cloning, mapping, and regulation of Pho regulon genes for phosphonate breakdown by the phosphonatase pathway of Salmonella typhimurium LT2.
(21/26)
Two pathways exist for cleavage of the carbon-phosphorus (C-P) bond of phosphonates, the C-P lyase and the phosphonatase pathways. It was previously demonstrated that Escherichia coli carries genes (named phn) only for the C-P lyase pathway and that Enterobacter aerogenes carries genes for both pathways (K.-S. Lee, W. W. Metcalf, and B. L. Wanner, J. Bacteriol. 174:2501-2510, 1992). In contrast, here it is shown that Salmonella typhimurium LT2 carries genes only for the phosphonatase pathway. Genes for the S. typhimurium phosphonatase pathway were cloned by complementation of E. coli delta phn mutants. Genes for these pathways were proven not to be homologous and to lie in different chromosomal regions. The S. typhimurium phn locus lies near 10 min; the E. coli phn locus lies near 93 min. The S. typhimurium phn gene cluster is about 7.2 kb in length and, on the basis of gene fusion analysis, appears to consist of two (or more) genes or operons that are divergently transcribed. Like that of the E. coli phn locus, the expression of the S. typhimurium phn locus is activated under conditions of Pi limitation and is subject to Pho regulon control. This was shown both by complementation of the appropriate E. coli mutants and by the construction of S. typhimurium mutants with lesions in the phoB and pst loci, which are required for activation and inhibition of Pho regulon gene expression, respectively. Complementation studies indicate that the S. typhimurium phn locus probably includes genes both for phosphonate transport and for catalysis of C-P bond cleavage. (+info)
Structural analysis of a novel triphosphonoglycosphingolipid from the egg of the sea hare, Aplysia kurodai.
(22/26)
A novel phosphonoglycosphingolipid which contains three residues of 2-aminoethylphosphonate (2-AEP) was isolated from eggs of a sea gastropoid, Aplysia kurodai, and its structure was identified as follows. [see text] The major aliphatic components of ceramide were palmitic acid, stearic acid, 4-sphingenine, and 16-methyl-4-sphingenine. Antibodies which recognize 3-O-methylgalactose linked beta-glycosidically to phosphonoglycosphingolipids failed to react to the egg glycolipid. By comparing 1H-NMR spectra of native and HF-treated glycolipids, steric interactions of two residues of 2-AEP with ring protons of the glucose and the internal galactose were indicated. (+info)
Oligonucleotides with novel, cationic backbone substituents: aminoethylphosphonates.
(23/26)
Oligonucleotide (2-aminoethyl)phosphonates in which the backbone consisted of isomerically pure, alternating (2-aminoethyl)-phosphonate and phosphodiester linkages have been prepared and characterized. One of these single isomer oligonucleotides (Rp) formed a more stable duplex with DNA or RNA than its corresponding natural counterpart. Hybrid stability was more pH-dependent, but less salt-dependent than a natural duplex. The specificity of hybridization was examined by hybridization of an oligonucleotide containing one (2-aminoethyl)phosphonate to oligonucleotides possessing mismatches in the region opposite to the aminoethyl group. In contrast to oligonucleotides containing (aminomethyl)-phosphonate linkages, oligonucleotide (2-aminoethyl)phosphonates were completely stable to hydrolysis in aqueous solution. These oligonucleotides were resistant to nuclease activity but did not induce RNase H mediated cleavage of a complementary RNA strand. Incubation in a serum-containing medium resulted in minimal degradation over 24 hours. Studies of cell uptake by flow cytometry and confocal microscopy demonstrated temperature dependent uptake and intracellular localization. (2-Aminoethyl)phosphonates represent a novel approach to the introduction of positive charges into the backbone of oligonucleotides. (+info)
Isolation of ceramide-monomethylaminoethylphosphonate from the lipids of Tetrahymena pyriformis W.
(24/26)
Ceramide-monomethylaminoethylphosphonate has been isolated for the first time from the lipids of Tetrahymena pyriformis W and characterized on the basis of its chromatographic mobility, chemical analysis, and infrared and nuclear magnetic resonance properties. (+info)