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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A modification of the traditional method for lipoplysaccharide isolation from the cells of grammnegative bacteria was elaborated on the basis of extraction by the hot water solution of phenol (the method of Westfahl). To make the method simpler and to raise the yield of the product it was proposed to use the water-phenol extract without its division for plases. The nucleic acids are eliminated by precipitation from dialyzed extract at pH 3,2-3,4 achieved by addition of acetic acid. The comparative isolation of lipopolysaccharides by the classic and modified methods has confirmed the advantages of a new technique.
Mol Gen Mikrobiol Virusol 1987 May
PMID:[Improved method of lipopolysaccharide isolation from gram-negative bacteria]. 311 64

The O-haptens of the major fraction (f5A) of B. abortus (Strains 2308 and 19) membrane bound smooth lipopolysaccharide (sLPS) were prepared by hydrolysis of f5A native sLPS in 1% acetic acid at 100 degrees C for 2 h. After hydrolysis, O-haptens were separated from Lipid A-protein complex by centrifugation, and from small fragments by ultrafiltration of molecular weight cut-off (MWCO) 1.0 X 10(3). These carbohydrate haptens were identified by precipitin-inhibition assay and further fractionated by both membrane filtration and dialysis. The size distributions of carbohydrate haptens of endotoxins (f5A) ranged from oligosaccharides up to polysacchandes of 1.0 X 10(4) MWCO. Three major fractions of MWCO 8.0-10.0 X 10(3), 3.5-5.0 X 10(3) and less than 1.0 X 10(3) from both strains 2308 and 19 contained more than 85% of the total immunoactive materials. These fractions of haptens were subjected to composition, proton and 13C NMR analysis and were found to be a homopolymer of alpha 1----2 linked, 4,5-dideoxy-4-formamido-D-mannose (N-formylperosamine), which is identical to O-haptens of B. abortus strain 119.3 and Yersinia enterocolitica serotype 0:9 and similar to Vibrio cholerae 569B (INABA). Fractions of these haptens exhibited similar inhibitory reactivities in a precipitin-inhibition assay as expressed as mumoles of monosaccharide of anhydro-N-formyl perosamine. They were about 480 times as active as Me alpha----DMan or DMan.
Mol Cell Biochem 1987 Jun
PMID:Structural and immunochemical characterization of the O-haptens of Brucella abortus lipopolysaccharides from strains 19 and 2308. 311 17

Until recently the alcohol dehydrogenase of Drosophila melanogaster was thought to act only in the first step of primary alcohol oxidation, producing an aldehyde. Instead, acetic acid is the main product of a two-step process. A rapid procedure was developed for the isolation and purification of two allozymes. The thermostability of the purified enzymes was found to be very different, t 1/2 at 35 degrees C, being 45 min and 130 min for ADH-F and ADH-71k respectively. The kinetic parameters of ethanol oxidation by the two purified allozymes were determined within physiological substrate and coenzyme ranges. The use of artificial electron acceptors has a notable influence on the ethanol oxidation: the apparent Michaelis constants increase; the oxidation rate with ADH-71k increases, whereas it decreases with ADH-F. Purified ADH is shown to be able to catalyze the oxidation of acetaldehyde solely in the presence of NAD+, and PMS and MTT as artificial electron acceptors. From the kinetic data the relative in vivo oxidation rates of ethanol by both ADH allozymes were calculated. ADH-F turned out to be somewhat less effective (30%-40%) than ADH-71k. The physiological consequences of these differences are discussed.
Mol Gen Genet 1985
PMID:Dual function of the alcohol dehydrogenase of Drosophila melanogaster: ethanol and acetaldehyde oxidation by two allozymes ADH-71k and ADH-F. 315 99

Peroxisomes were purified from livers of control mice and from mice treated with three agents which induce proliferation of hepatic peroxisomes - namely two structurally unrelated hypolipidemic drugs, clofibrate (ethyl-alpha-p-chlorophenoxyisobutyrate) and Wy-14,643 (4-chloro-6[2,3-xylidino)-2-pyrimidinylthio]acetic acid), and a plasticizer, DEHP (di-(2-ethylhexyl)phthalate). Membranes were isolated from these purified peroxisomes and analysed by SDS-polyacrylamide gel electrophoresis. All membranes which were tested, displayed two predominant integral membrane proteins of apparent molecular weights of 68 kDa and 70 kDa respectively, as well as a number of minor components. Treatment of animals with clofibrate, Wy-14,643 and DEHP was observed to result in each case in an increased proportion of the 70 kDa protein in the peroxisomal membranes. These treatments also resulted in increased peroxisomal fatty acid oxidation in livers and an increase in the proportion of catalase activity in the cytosolic fraction of liver cells. These results have been discussed in relation to alterations in the molecular composition of the membranes, the mechanisms of peroxisome proliferation and the inducibility of peroxisomal membrane proteins.
Mol Cell Biochem 1988 May
PMID:Changes to the integral membrane protein composition of mouse liver peroxisomes in response to the peroxisome proliferators clofibrate, Wy-14,643 and di(2-ethyl-hexyl)phthalate. 317 43

Abnormal desmosomes were found in the endometrial epithelial cells of rats treated orally with gossypol acetic acid at a dose of 60 mg/kg/day for 30 days. Desmosomes in the endometrium of rats treated at 40 mg/kg/day were similar to those of controls. Abnormalities included an increase in desmosome number with prominent filamentous interconnections, asymmetry, disorganization of tonofilaments, missing tonofilaments, missing desmosomal plaques that did not appear to line up with those of the adjacent cell. It is thought that the antifertility actions of gossypol may be due to a disturbance of desmosome formation. This would cause a disruption of endometrial cell adhesion as well as an alteration in the microenvironment within cytoplasmic domains. These changes could lead to an endometrial environment unfavorable to fetal development.
J Ultrastruct Mol Struct Res
PMID:An ultrastructural study of the effects of gossypol on the endometrium of the female rat. 326 9

Tumor cells produce a variety of hormones and growth factors that are associated with modulation of the growth pattern of malignant cells. Hs294T human malignant melanoma cells produce a monolayer mitogen, melanoma growth stimulatory activity (MGSA), that stimulates the growth of Hs294T cultures in serum-free medium. MGSA has been purified to homogeneity from conditioned medium of Hs294T human malignant melanoma cells using acetic acid extraction of the crude conditioned medium followed by three chromatographic processes, including gel-filtration, heparin-Sepharose, and reverse-phase HPLC. MGSA was eluted from the heparin-Sepharose resin with 0.1-0.3 M NaCl. The binding affinity is similar to that of platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) but much less than many endothelial cell-derived growth factors which require significantly higher salt concentrations for elution. These procedures resulted in a final yield of purified MGSA that was significantly greater than yields obtained using previously reported procedures. The homogeneous 16,000 and 13,000 molecular weight moieties obtained by means of these procedures exhibited similar bioactivities (stimulating a 2- to 3-fold increase in Hs294T cell growth) over a 0.06-6 ng concentration range. This bioactivity was progressively inactivated during storage at -80 degrees C. These results indicate that the combination of heparin-Sepharose chromatography and reverse phase-HPLC provides a more efficient means of purification of MGSA.
Mol Cell Endocrinol 1988 May
PMID:High yield purification of melanoma growth stimulatory activity. 339 57

Histamine-N-methyltransferase, a major histamine-degrading enzyme in the skin, was purified from guinea pig skin about 150-fold. The enzymological characteristics including pH optimum, Km values for substrates, and molecular weight were almost consistent with those reported in the brain. Regulatory mechanism of the enzyme activity by biogenic amines was investigated using the purified specimen. Serotonin, tryptamine, and 5-methoxytryptamine intensely inhibited the activity while tryptophan, melatonin, N-acetylserotonin, tryptophol, and 5-hydroxyindole acetic acid had no significant effects. Dopamine, tyramine, 3-methyltyramine, and phenylethylamine also inhibited the activity while no particular effects were obtained by adrenaline, noradrenaline, tyrosine, and DOPA. Spermidine and cadaverine caused significant but weaker inhibition. These amines acted competitively with respect to histamine, although varying manners were observed with respect to S-adenosyl-L-methionine. From these results, it was concluded that the enzyme activity was inhibited by such compounds in which a certain chemical structure, CH2-CH2-NH2 group neighboring the hydrophobic group, was contained. A possible mechanism of inhibition by the amines is postulated, and possible roles of such compounds in the inflammation by impairing the histamine metabolism is discussed.
Exp Mol Pathol 1986 Dec
PMID:Regulation of the activity of histamine-N-methyltransferase from guinea pig skin by biogenic amines. 379 10

Ribosomal 60S subunits active in polyphenylalanine synthesis can be reconstituted from core particles lacking 20-40% of the total protein. These core particles were obtained by treatment of yeast 60S subunits with dimethylmaleic anhydride, a reagent for protein amino groups. Upon reconstitution a complementary amount of split proteins is incorporated into the ribosomal particles, which have the sedimentation coefficient of the original subunits. Ribosomal protein fractions obtained by extraction with 1.25 M NH4Cl, 4 M LiCl, 7 M LiCl, or 67% acetic acid, are much less efficient in the reconstitution of active subunits from these core particles than the corresponding released fraction prepared with dimethylmaleic anhydride. Attempts to reconstitute active subunits from protein-deficient particles obtained with 1.25 M NH4Cl plus different preparations of ribosomal proteins, including the fraction released with dimethylmaleic anhydride, were unsuccessful. Therefore, under our conditions, of the disassembly procedures assayed only dimethylmaleic anhydride allows partial reconstitution of active 60S subunits.
Mol Cell Biochem 1985 Feb
PMID:Partial reconstitution of 60S ribosomal subunits from yeast. 388

Regiospecific syntheses of gamma- and alpha-conjugates of methotrexate and poly(L-lysine) are described. The alpha- and gamma-t-butyl esters, respectively, of methotrexate were coupled to poly(L-lysine) with diphenylphosphoryl azide in N,N-dimethylformamide, the ester-protecting group was cleaved with 15% hydrogen bromide in acetic acid, and small molecules were removed by dialysis. Poly(L-lysine) of Mr = 1,500-8,000 and 8,000-30,000 was used to prepare six different conjugates, which were characterized by ultraviolet absorbance measurement and quantitative amino acid analysis. The degree of substitution varied from one methotrexate per 4.7 lysines to one methotrexate per 10.2 lysines. Dihydrofolate reductase inhibition in a cell-free assay was observed with alpha- and gamma-conjugates, but the latter had the greater affinity (only 3-fold less than that of methotrexate itself). The binding of the conjugates exhibited a slight pH dependence, with affinity being greater at pH 7.2 than at pH 8.5 for both alpha- and gamma-conjugates. Toxicity to cultured rat hepatoma cells (H35) was also greater for the gamma-conjugates, and showed some dependence on the chain-length and degree of substitution of the poly(L-lysine) carrier. Cells resistant to methotrexate by virtue of a transport defect (H35R0.3 line) retained their sensitivity to the gamma-conjugate, but less so to the alpha-conjugate. There was also some retention of sensitivity in a more highly resistant cell line (H35R10) with impaired methotrexate transport and a concomitant increase in dihydrofolate reductase activity. gamma-Conjugation was likewise more favorable in cytotoxicity assays against L1210 murine leukemia cells, and there was partial retention of activity against highly methotrexate-resistant lines (L1210/R71 and L1210/R81) with a transport defect and/or an elevation of dihydrofolate reductase content. In antitumor assays against intraperitoneal L1210 leukemia in mice, a gamma-conjugate with Mr = 8,000-30,000 and one methotrexate per 5.5 lysines produced a 35-75% increase in lifespan when administered intraperitoneally at single doses equivalent to 10-20 mg/kg of methotrexate. A similar increase in lifespan with methotrexate alone on the single-dose regimen required 50-150 mg/kg. An alpha-conjugate of similar Mr and degree of substitution was inactive at nontoxic doses, as were other gamma-conjugates of lower Mr and/or degree of substitution.(ABSTRACT TRUNCATED AT 400 WORDS)
Mol Pharmacol 1985 Jan
PMID:Regiospecific gamma-conjugation of methotrexate to poly(L-lysine). Chemical and biological studies. 396 26

Acetate, propionate, ethanol and propanol were the predominant end-products released during incubation of a thiabendazole resistant and a susceptible strain of Trichostrongylus colubriformis. The parasites in all the incubations appeared to be deficient in reducing equivalents if the end-products arose from the classical catabolic pathway through fumarate reductase (EC 1.3.1.6). Possible alternative pathways for accounting for redox balance, including beta-oxidation, the pentose phosphate pathway and amino acid metabolism were investigated. Palmitate was oxidised aerobically. Radiolabelled tricarboxylic acid cycle intermediates, citrate and alpha-ketoglutarate, were decarboxylated to 14CO2 indicating that at least a partial tricarboxylic acid cycle to succinyl-CoA via alpha-ketoglutarate operates both anaerobically and aerobically in T. colubriformis. These data and the pattern of end-products suggest the presence of two pathways to propanol and propionate either through fumarate reduction or alpha-ketoglutarate oxidation. T. colubriformis may apportion carbon flow through these pathways to maintain a stable redox ratio. Similar calculations on previously reported data indicate that both pathways may also operate in Haemonchus contortus. Exposure of resistant T. colubriformis to thiabendazole under anaerobic conditions caused an increased accumulation of end-products, especially propanol, in the incubation medium. The alpha-ketoglutarate pathway may lower the dependence of the parasite on the fumarate reductase route which is sensitive to thiabendazole. The operation of the alpha-ketoglutarate pathway, with propanol as an end-product, may provide a mechanism for regulating redox balance in trichostrongylidae.
Mol Biochem Parasitol 1985 Mar
PMID:The contribution of a partial tricarboxylic acid cycle to volatile end-products in thiabendazole-resistant and susceptible Trichostrongylus colubriformis. 399 Jul 6


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