Showing papers on "Melibiose published in 1986"
TL;DR: It is concluded that the GAL3 gene product executes its function at a point before GAL4 mediated transcription of the G AL1-10-7 and MEL1 genes, which is consistent with the previously advanced hypothesis that theGAL2 gene product functions to synthesize the inducer or coinducer molecule.
Abstract: During the galactose adaptation period of a Saccharomyces cerevisiae strain bearing a naturally occurring gal3 allele, we found a longer induction lag and slower rate of accumulation of GAL10 and MEL1 RNAs compared to wild-type strains. A strain of genotype gal3 gal1 gal7 is noninducible for MEL1 gene expression, but this expression block is bypassed by overexpression of the GAL4 gene or by deletion of the GAL80 gene, either of which causes a constitutive phenotype. An otherwise wild-type strain that bears a chromosomal gal3 gene disruption mutation does not produce wild-type GAL3 RNA and exhibits induction comparable to a strain bearing the naturally occurring gal3. Based on this array of results, we conclude that the GAL3 gene product executes its function at a point before GAL4 mediated transcription of the GAL1-10-7 and MEL1 genes. Thus, the data are consistent with the previously advanced hypothesis that the GAL3 gene product functions to synthesize the inducer or coinducer molecule. In experiments in which the presence of either the plasmid-carried cloned GAL3 gene or the plasmid-carried cloned GAL1-10-7 genes allows MEL1 induction of a gal3 gal1 gal7 cell, we find that loss of the plasmid results in the shutoff of MEL1 expression even when galactose is continuously present. Either GAL3 function or GAL1-10-7 functions are therefore required for both the initiation and the maintenance of the induced state. Since the strains bearing either the naturally occurring gal3 allele or the gal3 disruption (null) allele do induce, the plasmid loss experiments indicate the existence of two completely independent induction initiation-maintenance pathways, one requiring GAL3 function, the other requiring GAL1-10-7 function. Finally, Northern blot analysis reveals two major GAL3 transcripts that differ in size by approximately 500 nucleotides.
67 citations
TL;DR: Quantitative analysis of the effects of H+ and Na+ ions on the parameters of Np alpha Gal binding show that the maximal number of binding sites is constant irrespective of the concentration of Na+ or Li+ in the range of pH between 6 and 7.5 and the apparent dissociation constant for Npalpha Gal binding varies with both Na+ and H+.
66 citations
01 Jan 1986
TL;DR: In this paper, the effect of H+ and Na+ ions on NpaGal binding to de-energized membrane vesicles from Escherichia coli RAll was analyzed by studying [3Hlp-nitrophenyl-a-~galactopyranoside (NpaGal) binding.
Abstract: The substrate binding reaction of the melibiose carrier was analyzed by studying [3Hlp-nitrophenyl-a-~galactopyranoside (NpaGal) binding to de-energized membrane vesicles from Escherichia coli RAll as a function of H+ and Na+ (or Li+) concentrations. The data indicate first that Na+ (or Li+) activates NpaGal binding at all pH values tested between 5.5 and 7.5 and second that H+ inhibits the Na+ (or Li+)-dependent activating effect on NpaGal binding. Similar conclusions were drawn for melibiose and methyl-l-thio-8D-galactoside binding activities. Unexpectedly, NpaGal, melibiose, and methyl- l-thio-&~-galactoside binding activities are insensitive to a variety of SH reagents which completely block transport activity. Quantitative analysis of the effects of H+ and Na+ ions on the parameters of NpaGal binding show that 1) the maximal number of binding sites is constant irrespective of the concentration of Na+ or Li+ in the range of pH between 6 and 7.5 and 2) the apparent dissociation constant for NpaGal binding varies with both Na+ and H+ according to a relation described by a linear combination of the concentration of H+ and the reciprocal of Na+ concentration. These results can be accounted for by a model which assumes sequential binding of the cation and substrate in this order and competition between Na+ and H+ for a common cationic binding site on the porter. Predictions of the proposed binding model for a carrier mechanism catalyzing sugar transport according to a Na+ symport mode or a H+ symport mode are discussed.
54 citations
TL;DR: P. heimbachae strains are gram-negative, oxidase- negative, fermentative, rod-shaped organisms that grow on MacConkey agar, as well as other media that are selective for members of the Enterobacteriaceae.
Abstract: The name Providencia heimbachae sp. nov. is proposed for a group of organisms that were isolated from the feces of penguins in the Federal Republic of Germany and from a cow in the United States. P. heimbachae strains are gram-negative, oxidase-negative, fermentative, rod-shaped organisms that grow on MacConkey agar, as well as other media that are selective for members of the Enterobacteriaceae. The 13 P. heimbachae isolates which we studied gave negative results for the following tests: indole production, Voges-Proskauer, Simmons citrate, H2S production on triple sugar iron and Kligler agars, urease, lysine decarboxylase, arginine dihydrolase, gelatinase, growth in the presence of KCN, malonate, acid production from L-arabinose, cellobiose, dulcitol, erythritol, lactose, melezitose, melibiose, a-methylglucoside, raffinose, salicin, D-sorbitol, L-sorbose, starch, D-tagatose, trehalose, D-turanose, and D-xylose (15% positive after 7 days), esculin hydrolysis, acetate, lipase, deoxyribonuclease, and o-nitrophenyl-β-D-galactopyranoside. The strains were positive for the following tests: catalase, nitrate reductase, methy1 red, phenylalanine deaminase, acid production from D-glucose, adonitol, D-arabitol, D-fructose, D-galactose, D-mannose, and L-rhamnose, and tyrosine clearing. Acid production from glycerol, myo-inositol, maltose, and D-mannitol was delayed; gas was produced from D-glucose, D-galactose, and D-mannose in small amounts or not at all (54% positive after 7 days). Motility at 36°C was variable (46% positive after 2 days; 85% positive after 7 days). Deoxyribonucleic acids from 12 other strains of P. heimbachae were highly related (91 to 100% related in reactions assayed on hydroxyapatite at 60 and 75°C) to 32P-labeled deoxyribonucleic acid from the proposed type strain (strain ATCC 35613). Labeled deoxyribonucleic acid from this type strain was 22 to 45% related at 60°C and 4 to 31% related at 75°C to deoxyribonucleic acids from four other Providencia species. The levels of relatedness of P. heimbachae to Proteus species ranged from 10 to 13% in 60°C reactions. P. heimbachae could be differentiated from the other Providencia species by the following characteristics: negative tests for Simmons citrate, urease, indole production, and acid production from trehalose and positive tests for acid production from adonitol, D-arabitol, D-galactose, and L-rhamnose. All of the P. heimbachae strains which we studied were resistant to tetracycline, and most strains were resistant to cephalothin.
39 citations
TL;DR: Results of other experiments provided evidence that raffinose was partly converted to 6''-carboxyraffinose when treated with galactose oxidase and catalase, and indicate that galactOSE oxidase not only converts the C-6 hydroxymethyl group of Galactose to an aldehyde group, but also catalyzes further oxidation to the carboxyl group.
34 citations
TL;DR: The lectin shows a stimulatory effect on the superoxide anion production by guinea-pig polymorphonuclear leukocytes, and the effect is inhibited, among various sugars, most strongly by melibiose.
32 citations
TL;DR: Melibiose, a suitable non-permeating osmoticum for selective separation of Na6(CO3)(SO4)2, Na2SO4 from Na2CO3 using a high-performance liquid chromatography apparatus.
Abstract: Dracup, M., Gibbs, J. and Greenway, H. 1986. Melibiose, a suitable non-permeating osmoticum for
32 citations
TL;DR: A Monascus pilosus strain was selected for production of intracellular α-galactosidase and the enzyme was purified by ammonium sulfate precipitation, gel filtration, and ion exchange chromatography and was demonstrated to be homogeneous by slab gel electrophoresis.
Abstract: A Monascus pilosus strain was selected for production of intracellular α-galactosidase. Optimum conditions for mycelial growth and enzyme induction were determined. Galactose was one of the best enzyme inducers. The enzyme was purified by ammonium sulfate precipitation, gel filtration, and ion exchange chromatography and was demonstrated to be homogeneous by slab gel electrophoresis. The molecular weight of this enzyme, estimated by gel filtration, was about 150,000. The optimum conditions for the enzyme reaction was pH 4.5 to 5.0 at 55°C. The purified enzyme was stable at 55°C or below and in buffer at pH 3 to 8. The activity was inhibited by mercury, silver, and copper ions. The kinetics of this enzyme, with p-nitrophenyl-α-d-galactoside as substrate, was determined: Km was about 0.8 mM, and Vmax was 39 μmol/min per mg of protein. Enzymatic hydrolysis of melibiose, raffinose, and stachyose was analyzed by thin-layer chromatography.
31 citations
TL;DR: Aspergillus oryzae QM 6737 was grown in solid state culture to produce α-galactosidase extracellularly in wheat bran, 35% initial moisture, after 5 days at 32°C with agitation as discussed by the authors.
Abstract: Aspergillus oryzae QM 6737 was grown in solid state culture to produce α-galactosidase extracellularly. An optimum enzyme yield of ∼ 3 units/g solid was obtained on wheat bran, 35% initial moisture, after 5 days at 32°C, with agitation. Higher initial moisture levels reduced enzyme production. Higher yields were obtained by adding glucose (73% increase), sucrose (39% increase), or melibiose (39% increase) to the bran, but raffinose and stachyose had little or no effect. Enzyme yield increased three times when soy flour or soy beans was used as substrate but no enzyme production was observed using rice. Enzyme production on soy beans decreased with increased initial moisture levels and with decreased particle size.
24 citations
TL;DR: The results indicate that maltose shares a common transport system with sucrose and that there may be some interaction between the uptake systems for lactose, cellobiose, and glucose.
Abstract: Trichosporon cutaneum is shown to utilize six disaccharides, cellobiose, maltose, lactose, sucrose, melibiose, and trehalose. T. cutaneum can thus be counted with the rather restricted group of yeasts (11 to 12% of all investigated) which can utilize lactose and melibiose. The half-saturation constants for uptake were 10 +/- 3 mM sucrose or lactose and 5 +/- 1 mM maltose, which is of the same order of magnitude as those reported for Saccharomyces cerevisiae. Our results indicate that maltose shares a common transport system with sucrose and that there may be some interaction between the uptake systems for lactose, cellobiose, and glucose. Lactose, cellobiose, and melibiose are hydrolyzed by cell wall-bound glycosidase(s), suggesting hydrolysis before or in connection with uptake. In contrast, maltose, sucrose, and trehalose seem to be taken up as such. The uptake of sucrose and lactose is dependent on a proton gradient across the cell membrane. In contrast, there were no indications of the involvement of gradients of H+, K+, or Na+ in the uptake of maltose. The uptake of lactose is to a large extent inducible, as is the corresponding glycosidase. Also the glycosidases for cellobiose, trehalose, and melibiose are inducible. In contrast, the uptake of sucrose and maltose and the corresponding glycosidases is constitutive.
21 citations
TL;DR: Methods used for measuring the transport of both the sugar and cation substrates are described, some of these methods such as the preparation of radioactive melibiose and the construction of the Li+-selective electrode were devised specifically for studies of theMelibiose transport system.
Abstract: Publisher Summary This chapter describes methods used for measuring the transport of both the sugar and cation substrates. Some of these methods such as the preparation of radioactive melibiose and the construction of the Li+-selective electrode were devised specifically for studies of the melibiose transport system. The melibiose carrier of Escherichia coli is a representative of the class of carriers that require a cation for cotransport. An unusual feature of this transport system is that it is able to utilize Na + , Li + , or H + as the coupling cation depending on the conditions. Another interesting property of the carrier is that different sugar substrates show different specificities for the cation requirement. A variety of strains of E. coli has been isolated for use in experiments on the melibiose carrier. It is essential to start with a strain from which the lactose carrier (lac Y) has been deleted, as the lac carrier also is capable of transporting melibiose. The growth of normal E. coli cells on melibiose minimal medium is strongly inhibited by 10 mM Li + and it is therefore possible to isolate Li + -resistant mutants. This organism is dependent on Na + or Li + for growth on melibiose as it has lost the ability to transport the disaccharide with protons.
TL;DR: The purified enzyme was proved to be almost homogeneous by polyacrylamide gel electrophoresis, and highly specific to sucrose as substrate, having only 10% as much activity toward raffinose as that toward sucrose, and being inert toward other disaccharides.
TL;DR: A Lac+ mutant of Erwinia chrysanthemi was isolated from the Lac- wild type on lactose agar and melibiose was a strong inhibitor of both the Melibiose- and the raffinose-induced lactose permeases.
Abstract: A Lac+ mutant of Erwinia chrysanthemi was isolated from the Lac- wild type on lactose agar. beta-Galactosidase was expressed independently of lactose transport in both the mutant and the wild type, and neither strain expressed thiogalactoside transacetylase. Lactose transport and alpha-galactosidase, constitutive in the Lac+ strain, were coordinately induced in the Lac- strain by melibiose and raffinose but not by isopropyl-beta-D-thiogalactopyranoside or thiomethyl-beta-D-galactopyranoside. Melibiose was a strong inhibitor of both the melibiose- and the raffinose-induced lactose permeases, whereas raffinose was a strong inhibitor of only the raffinose-induced lactose permease.
TL;DR: In this paper, the stereochemistry of the enzymatic cleavage of saccharose and raffinose by invertase from Candida util is, β-D-fructofuranosi-de fructohydrolase (EC 3.2.1.26), was investigated.
TL;DR: In this paper, it was found that cell-free extracts of these microorganisms hydrolyzed mono-and digalactosyldiglycerides, melibiose, and raffinose.
Patent•
29 Sep 1986
TL;DR: In this article, a host-vector system of Bacillus subtilis, remarkably, by adding a specific sugar to the medium was used to improve the staphylokinase productivity.
Abstract: PURPOSE:To improve the staphylokinase productivity in the process utilizing a host-vector system of Bacillus subtilis, remarkably, by adding a specific sugar to the medium. CONSTITUTION:A mutant of Bacillus subtilis 168rec [e.g. Bacillus subtilis 168YIT6007 (FERM-P 7326), YIT6008 (FERM-P 7464) or YIT6009 (FERM-P 7365)] is transformed with a recombinant plasmid (e.g. pHSAK565) produced by integrating a staphylokinase(SAK-producing gene in the plasmid vector of Bacillus subtilis 168 strain (e.g. pUB110, pC194, pHY600, pHY460 or their derivative). The obtained transformation is cultured in a conventional medium for the cultivation of Bacillus subtilis to produce SAK. In the above process, the medium is added with a sugar selected from glucose, fructose, sucrose and melibiose. The SAK-productivity of Bacillus subtilis having recombinant plasmid containing SAK gene can be improved remarkably by this process.