Showing papers on "Melibiose published in 1980"
TL;DR: Y. intermedia is positive in reactions for melibiose, raffinose, α-methyl-d-glucoside, rhamnose, and usually Simmons' citrate, and it is metabolically more active at 22–28°C than at 35–37°C.
Abstract: Yersinia intermedia sp. nov. is defined biochemically and genetically.Y. intermedia strains belong to a single DNA relatedness group that is separable fromY. enterocolitica, Y. frederiksenii, Y. kristensenii, andY. pseudotuberculosis. Y. intermedia is positive in reactions for melibiose, raffinose, α-methyl-d-glucoside, rhamnose, and usually Simmons' citrate. It is metabolically more active at 22–28°C than at 35–37°C. These positive reactions serve to distinguishY. intermedia fromY. enterocolitica andY. kristensenii. Positive melibiose, raffinose, and α-methyl-d-glucoside reactions differentiateY. intermedia from the other new rhamnose-positive species,Y. frederiksenii. Y. intermedia is separated fromY. pseudotuberculosis by its positive reactions for sucrose, indole, cellobiose,i-inositol,d-sorbitol, α-methyl-d-glucoside, and ornithine decarboxylase.Yersinia biotype X2, an additional rhamnose-positive, sucrose-negative group, as yet not identified to a species, and X1, a sucrose- and ornithine decarboxylase-negativeYersinia biotype, do not belong toY. intermedia. Strain 3953 (=CIP 80-28=ATCC 29909=Bottone 48=Chester 48) is proposed as the type strain forY. intermedia.
111 citations
TL;DR: These strains formed four distinct DNA relatedness groups: the 5 classical biotypes ofY.
Abstract: Yersinia enterocolitica andY. enterocolitica-like strains were characterized by DNA relatedness. These strains formed four distinct DNA relatedness groups: (i) the 5 classical biotypes ofY. enterocolitica sensu stricto as designated by Wauters; (ii) strains that are rhamnose positive and also positive in tests for melibiose, α-methyl-d-glucoside, raffinose, and Simmons' citrate; (iii) strains that are rhamnose positive but negative in tests for melibiose, α-methyl-d-glucoside, and raffinose; (iv) sucrose-negative, Voges-Proskauer-negative, trehalose-positive strains.
78 citations
TL;DR: This paper reports some biochemical characteristics of a second L-proline transport system in Salmonella typhimurium and finds that it is an active transport system with an apparent Km for L- Proline of 3 x 10(-4) M and a strict specificity for L -proline and some of its analogs.
Abstract: This paper reports some biochemical characteristics of a second L-proline transport system in Salmonella typhimurium. In the accompanying paper, R. Menzel and J. Roth (J. Bacteriol. 141:1064--1070, 1980) have identified this system by showing that it is inactivated by mutations at the locus proP. We have found that it is an active transport system with an apparent Km for L-proline of 3 x 10(-4) M and a strict specificity for L-proline and some of its analogs. Unlike the L-proline transport system encoded in putP, this second system is induced by amino acid limitation.
47 citations
TL;DR: Bandeiraea simplicifolia I (BS I) isolectins, immobilized on Sepharose beads, specifically retarded low molecular weight ligands containing terminal cu-o-galactopyranosyl and 2acetamido-2-deoxy-a-D-galactoranosyl residues to perform very efficient separations of structurally homologous sugar nucleotides and oligosaccharides.
38 citations
TL;DR: Two forms of α-galactosidase which differed in molecular weight were resolved from Cucumis sativus L.C. leaves and both enzymes were inhibited by galactose as well as by excess concentrations of p -nitrophenyl-α-d-Galactoside sub-strate.
Abstract: Two forms of α-galactosidase (α-d-galactoside galactohydrolase, E.C. 3.2.1.22) which differed in molecular weight were resolved from Cucumis sativus L. leaves. The enzymes were partially purified using ammonium sulfate fractionation, Sephadex gel filtration, and diethylaminoethyl-Sephadex chromatography. The molecular weights of the two forms, by gel filtration, were 50,000 and 25,000. The 50,000-dalton form comprised approximately 84% of the total α-galactosidase activity in crude extracts from mature leaves and was purified 132-fold. The partially purified 25,000-molecular weight form rapidly lost activity unless stabilized with 0.2% albumin and accounted for 16% of the total α-galactosidase activity in the crude extract. The smaller molecular weight form was not found in older leaves. The two forms were similar in several ways including their pH optima which were 5.2 and 5.5 for the 50,000- and 25,000-dalton form, respectively, and activation energies, which were 15.4 and 18.9 kilocalories per mole for the larger and smaller forms. Both enzymes were inhibited by galactose as well as by excess concentrations of p -nitrophenyl-α-d-galactoside sub-strate. K m values with this substrate and with raffinose and melibiose were different for each substrate, but similar for both forms of the enzyme. With stachyose, K m values were 10 and 30 millimolar for the 50,000- and 25,000- molecular weight forms, respectively.
35 citations
01 Jan 1980
TL;DR: Two forms of a-galactosidase (a-t-Galactoside galactohydrolase, E.C. 3.22) which differed in molecular weight were resolved from Cucumis sativus L. leaves as mentioned in this paper.
Abstract: Two forms of a-galactosidase (a-t-galactoside galactohydrolase, E.C. 3.2.1.22) which differed in molecular weight were resolved from Cucumis sativus L. leaves. The enzymes were partially purified using ammonium sulfate fractionation, Sephadex gel filtration, and diethylaminoethyl-Sephadex chromatography. The molecular weights of the two forms, by gel filtration, were 50,000 and 25,000. The 50,000-dalton form comprised approximately 84% of the total a-galactosidase activity in crude extracts from mature leaves and was purified 132-fold. The partially purified 25,000molecular weight form rapidly lost activity unless stabilized with 0.2% albumin and accounted for 16% of the total a-galactosidase activity in the crude extract. The smaller molecular weight form was not found in older leaves. The two forms were similar in several ways including their pH optima which were 5.2 and 5.5 for the 50,000- and 25,000-dalton form, respectively, and activation energies, which were 15.4 and 18.9 kilocalories per mole for the larger and smaller forms. Both enzymes were inhibited by galactose as well as by excess concentrations of p-nitrophenyl-a-D-galactoside substrate. Km values with this substrate and with raffinose and melibiose were different for each substrate, but similar for both forms of the enzyme. With stachyose, Km values were 10 and 30 millimolar for the 50,000- and 25,000molecular weight forms, respectively.
35 citations
TL;DR: Melibiose transport in Salmonella typhimurium was investigated and it was concluded that the mechanism for Na+ extrusion is an Na-/H+ antiport, a transformer which converts an electrochemical H+ gradient to an Na+ gradient, which then drives melibiose Transport.
Abstract: Melibiose transport in Salmonella typhimurium was investigated. Radioactive melibiose was prepared and the melibiose transport system was characterized. Na+ and Li+ stimulated transport of melibiose by lowering the Km value without affecting the Vmax value; Km values were 0.50 mM in the absence of Na+ or Li+ and 0.12 mM in the presence of 10 mM NaCl or 10 mM LiCl. The Vmax value was 140 nmol/min per mg of protein. Melibiose was a much more effective substrate than methyl-beta-thiogalactoside. An Na+-melibiose cotransport mechanism was suggested by three types of experiments. First, the influx of Na+ induced by melibiose influx was observed with melibiose-induced cells. Second, the efflux of H+ induced by melibiose influx was observed only in the presence of Na+ or Li+, demonstrating the absence of H+-melibiose cotransport. Third, either an artificially imposed Na+ gradient or membrane potential could drive melibiose uptake in cells. Formation of an Na+ gradient in S. typhimurium was shown to be coupled to H+ by three methods. First, uncoupler-sensitive extrusion of Na+ was energized by respiration or glycolysis. Second, efflux of H+ induced by Na+ influx was detected. Third, a change in the pH gradient was elicited by imposing an Na+ gradient in energized membrane vesicles. Thus, it is concluded that the mechanism for Na+ extrusion is an Na+/H+ antiport. The Na+/H+ antiporter is a transformer which converts an electrochemical H+ gradient to an Na+ gradient, which then drives melibiose transport. Li+ was inhibitory for the growth of cells when melibiose was the sole carbon source, even though Li+ stimulated melibiose transport. This suggests that high intracellular Li+ may be harmful.
32 citations
TL;DR: Melibiose uptake via the lactose system was not temperature sensitive, was inhibited by lactose, and was not affected by Na+ and Li+.
Abstract: Transport of [3H]melibiose, prepared from [3H]raffinose, was investigated in Escherichia coli. Na+ stimulated the transport of melibiose via the melibiose system, whereas Li+ inhibited it. Kinetic parameters of melibiose transport were determined. The Kt values were 0.57 mM in the absence of Na+ or Li+, 0.27 mM in the presence of 10 mM NaCl, and 0.29 mM in the presence of 10 mM LiCl. The Vmax values were 40 and 46 nmol/min per mg of protein in the absence and in the presence of NaCl and 18 nmol/min per mg of protein in the presence of LiCl. Melibiose transport via the melibiose system was temperature sensitive in a wild-type strain of Escherichia coli and was not inhibited by lactose. On the other hand, melibiose uptake via the lactose system was not temperature sensitive, was inhibited by lactose, and was not affected by Na+ and Li+. Methyl-beta-D-thiogalactoside, a substrate for both systems, inhibited the transport of melibiose via both systems.
29 citations
TL;DR: Results suggest that sup mutants have an altered cyclic adenosine monophosphate receptor protein which is activated by cyclic guanosine monphosphate and has an increased affinity for cyclicAdenosine Monophosphates.
Abstract: Strain MM6-13 (ptsI suc lacI sup) of Escherichia coli contains a suppressor of the succinate-negative phenotype In MM6-13, sup caused enhanced growth in glycerol, maltose, melibiose, and succinate media and increased activity of beta-galactosidase and tryptophanase relative to an isogenic strain without sup In strain A61 (cya sup), sup partially suppressed cya Cyclic guanosine monophosphate increased beta-galactosidase activity sevenfold in A61 and enabled this strain to grow on maltose, galactose, succinate, and arabinose Strain A61 responded to much lower concentrations of cyclic adenosine monophosphate than cyclic guanosine monophosphate It appears that sup is located in the crp locus These results suggest that sup mutants have an altered cyclic adenosine monophosphate receptor protein which is activated by cyclic guanosine monophosphate and has an increased affinity for cyclic adenosine monophosphate
21 citations
TL;DR: Two molecular forms of alpha-galactosidase synthesized constitutively by Bacillus stearothermophilus, strain AT-7, have been purified and suggest that both enzymes consist of four subunits.
Abstract: Two molecular forms of α-galactosidase (EC 32122) synthesized constitutively by Bacillus stearothermophilus, strain AT-7, have been purified α-Galactosidase I (with the substrate p-nitrophenyl α-D-galactopyranoside (PNPG)) has a pH optimum of 6 and a half-life at 65 °C of > 2 h at low protein concentration α-Galactosidase II has a pH optimum of 7 with PNPG and a half-life at 65 °C of about 3 min The isozymes also differ with respect to their Km with PNPG and melibiose Both enzymes are inhibited competitively by D-galactose, melibiose, and Tris With the β-glycosides cellobiose and lactose either noncompetitive or mixed-type inhibition is observed, with the pattern dependent on both the pH and the isozyme The two isozymes have similar Arrhenius activation energies (about 20 kcal/mol, 1 kcal = 4184 kJ) Their molecular weights, estimated by disc gel electrophoresis, are α-galactosidase I, 280 000 ± 30 000 and α-galactosidase II, 325 000 ± 15 000 Dodecyl sulfate gel electrophoresis gave a single ba
17 citations
TL;DR: It was found empirically that In (C/C0) was linear in Q−1, with the absolute value of the slope decreasing with increasing C0, and the linearity of such plots were predicted by Lewis and Middleman from Waterland et al. for a single enzyme system obeying first‐order kinetics.
Abstract: Summary Raffinose was converted enzymatically in a hollow-fiber reactor to melibiose, sucrose, galactose, glucose, and fructose. The enzymes were a crude extract of ex galactosidase and invertase produced by Aspergillus awamori NRRL 4869 on a solid substrate, wheat bran. With a concentration of raffinose, Co, entering the reactor at a flow rate Q, and with C being the concentration of raffinose exiting the reactor, the conversion (C/ Co), was studied as a function of Q at two levels of Co' The data could be fairly well fitted using the analysis of Waterland et al. even though a mixed crude enzyme system was being investigated. It was found empirically that In (C/ Co) was linear in Q-l, with the absolute value of the slope decreasing with increasing Co. The linearity of such plots were predicted by Lewis and Middleman from Waterland et al. for a single enzyme system obeying first-order kinetics, the slope being independent of Co. Although the assumptions involved in this approximate analytical solution are riot valid, the observed linearity of the In(C/Co) vs. Q-l plots is excellent and should prove useful in reactor design considerations.
TL;DR: A high incidence of antibodies to melibiose was observed and there were also a few antibodies to other sugars and to dextran.
Abstract: Human sera were screened by passive haemagglutination for antibodies to various sugars. A high incidence of antibodies to melibiose was observed. There were also a few antibodies to other sugars and to dextran.
TL;DR: Non-sterilized adult olive fruit flies were able to survive and reproduce on mannose, glucose, fructose, sucrose, melibiose, trehalose, maltose, melezitose, and sorbitol, indicating that sterilization with a 10 Krad dose did not affect their ability to utilize various carbohydrates.
01 Jan 1980
TL;DR: Observations indicate that there is an obligatory coupling between H+ flux and melibiose or alpha MG flux through the carrier when Na+ is omitted from the incubation medium.
Abstract: Proton entry into anaerobic Escherichia coli in response to the addition of HC1 was measured by monitoring pH changes in the external solution. Preincubation of cells in a Na+-free medium containing melibiose or methyl-α-galactoside (αMG) stimulated the rate of H+ entry in response to the acid pulse. This melibiose- or αMG-dependent proton pathway appeared to be identical to the melibiose carrier, since the channel was only observed in melibiose-induced cells. Furthermore, this membrane pathway for protons showed the same temperature sensitivity as the melibiose carrier (active at 30° but inactive at 37°). These observations are consistent with the idea that the melibiose transport system provides a pathway for protons in the presence of appropriate substrates, but that the pathway is closed to protons in the absence of the sugar. Such observations indicate that there is an obligatory coupling between H+ flux and melibiose or αMG flux through the carrier when Na+ is omitted from the incubation medium.
TL;DR: Twenty-fourYersinia enterocolitica-like strains were isolated from heavily contaminated river water and serological typing showed that the strains belonged to the serotypes O:1, O:14,O:38 and O:55, and four strains had a K-antigen linked to a complex antigenic structure.
Abstract: Twenty-fourYersinia enterocolitica-like strains were isolated from heavily contaminated river water. Twenty-three of the strains could only be isolated on deoxycholate-hydrogen sulfidelactose agar after cold-enrichment in tryptone soya broth. Biochemically, these strains exhibited the common properties ofY. enterocolitica. However, most strains were also melibiose-, rhamnose-, raffinose-, and Simmons’ citrate-positive. Two strains fermented lactose. The serological typing showed that the strains belonged to the serotypes O:1, O:14, O:38 and O:55. Four strains had a K-antigen linked to a complex antigenic structure. Two strains were autoagglutinated. One strain was agglutinated by two different serotypes. The strains belonged to the phage types Xo and Xz.
TL;DR: Constituent monomers of the polysaccharide fraction of ovary exudates obtained from flowering Aptenia cordifolia-plants were separated using anion exchange chromatography of their borate complexes and were analysed subsequently by colorimetric detection.
01 Aug 1980-Zentralblatt für Bakteriologie. 1. Abt. Originale A, Medizinische Mikrobiologie, Infektionskrankheiten und Parasitologie
TL;DR: 19 weakly saccharolytic Bacteroides strains of different species were tested by thin-layer chromatography (TLC) for their fermentative abilities for fructose, sucrose, lactose, galactose, and raffinose and a good agreement between both methods was recorded.
TL;DR: The lipopolysacharide from Pseudomonas aeruginosa strain BI contains the receptors for phage 2 and strongly inactivates this phage in vitro (95-98% within 15 min), suggesting the possibility thatphage 2 receptors in lipopolysaccharide contain L-rhamnose, D-glucosamine, and (or) D- glucose, or a structurally related molecule.
Abstract: The lipopolysacharide from Pseudomonas aeruginosa strain BI contains the receptors for phage 2 and strongly inactivates this phage in vitro (95-98% within 15 min). Several mono- and di-saccharides tested reduced phage 2 inactivation to 50% when present at the following concentrations: D-glucosamine, 0.25 M; maltose, 0.3M; lactose and cellobiose, 0.5 M; D-glucose, L-rhamnose, D-mannose, 2-deoxy-D-glucose, and sucrose, 1.0 M; D-galactose, D-xylose, and N-acetyl-D-glucosamine, 1.4 M; and melibiose. greater than 1.6 M. These results suggest the possibility that phage 2 receptors in lipopolysaccharide contain L-rhamnose, D-glucosamine, and (or) D-glucose, or a structurally related molecule. Either one of the latter two could be located at a terminal position alpha-linked to the adjacent residue, or located internally in the polysaccharide chain linked through its C-4 position.
TL;DR: The self-inhibition of binding activity at high protein concentrations arises from a competition between ligant binding by oligomers and self-association of these oligomers into multimeric species which have little or no binding acitivity.
Journal Article•
TL;DR: In this paper, Ethanolic extracts containing soluble sugars were prepared from four foods : cassava, peanut, coconut and papaye, which were given by stomach tube 10 mM CaCl2 solution (+ 45Ca) containing a carbohydrate.
Abstract: Ethanolic extracts containing soluble sugars were prepared from four foods : cassava, peanut, coconut and papaye. Six-month-old rats were given by stomach tube 10 mM CaCl2 solution (+ 45Ca) containing a carbohydrate. Depending on the group, the carbohydrate was glucose or melibiose or raffinose at 200 mM concentration, or one ethanolic extract. Blood samples were taken at different times after the administration and plasma radioactivity was measured. Rats were sacrificed at 24 hours; femur radioactivity was used as a measure of calcium absorption. Extracts of cassava, peanut, and papaye were the more patent in promoting calcium absorption. Extracts of coconut were less effective. This physiological activity of the extracts was correlated with the nature of sugars, identified by paper chromatography. Cassava contained raffinose, peanut included fructose, raffinose and stachyose. Fructose was abundant in papaye but in little quantity in coconut. The present experiments or earlier works had showed that these sugars enhanced calcium utilization.