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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have studied the effects of 2,3-diphosphoglycerate (2,3-DPG), 3-phosphoglycerate (3-PG), 3-phosphoglyceraldehyde (3-PGA), 2-phosphoglycerate (2-PG) and beta-glycerol phosphate (beta-GP) on platelet aggregation and on thromboxane B2 (TXB2) formation. The results show that 2,3-DPG, 3-PG, and 3-PGA inhibited platelet aggregation and TXB2 formation induced by norepinephrine, ADP, epinephrine, and collagen; but they also induced platelet aggregation and TXB2 formation in the presence of subthreshold concentrations of Na arachidonate. 2-PG and beta-GP were inactive. The results also show that there is a structure-function relationship between 2,3-DPG, 3-PG, and 3-PGA with platelet aggregation phenomena and prostaglandin synthesis.
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PMID:Structure-function relationship of 3-phosphoglycerate analogues with platelet aggregation and thromboxane A2 formation. 359 60

The Streptococcus mutans group b antigen of strain FA1 has been defined as to chemical composition and immunological specificity. The antigen in cold trichloroacetic acid extracts was fractionated on diethylaminoethyl-Sephadex A-25 at pH 8.5. Two forms were isolated: a polysaccharide and a mucoprotein. The two polymers reacted as a single substance in agar gel diffusion against specific adsorbed FA1 rabbit antisera but were separated by gel immunoelectrophoresis. No reaction with any other S. mutans or streptococcal group sera occurred. Galactose composed about one-third and galactosamine about 3% of the total weight of each polymer. Rhamnose was a major component of the polysaccharide (47%) but was present only in traces in the mucoprotein. The protein content of the latter was about 40%. No significant quantities of glycerol, phosphorus, or muramic acid were present in either case. Pepsin and trypsin had no effect on the serological specificity of the mucoprotein. d-Galactose and d-galactosamine were strong inhibitors (70%) of the precipitin reaction, whereas d-glucose, d-glucosamine, and N-acetyl-d-glucosamine inhibited between 25 and 35%. The results indicate that the antigen is a major antigenic component of the cell wall and that the specificity of the antigen resides in binding sites which contain both d-galactose and d-galactosamine. Agglutination of whole cells by specific group b antiserum indicates the antibody receptor sites of the polysaccharide antigen are at the surface of the streptococcal cell. The mucoprotein, but not the polysaccharide, was released from the cell by lysozyme. Lysis did not occur. The immunological specificity and other characteristics of the antigen establishes it as the identifying antigen of S. mutans group b.
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PMID:Structure and immunological specificity of the Streptococcus mutans group b cell wall antigen. 412 3

Cryogenically frozen vegetative cells of Bacillus licheniformis 9945a derived from young mucoid colonies were used to inoculate gamma-poly(glutamate) (gamma-PGA) production media containing L-glutamate, citrate and glycerol as carbon sources. A gel permeation chromatography (GPC) method was developed to determine gamma-PGA volumetric yield and molecular weight directly using culture filtrates. For GPC volumetric yield measurements, a calibration curve was generated using purified gamma-PGA to relate the gamma-PGA GPC peak area and polymer weight. Purified gamma-PGA was characterized by elemental analysis, 1H- and 13C-NMR spectroscopy. Cultures of B. licheniformis using all three carbon sources showed the following characteristics: cell growth mainly during the first 24 h; largest gamma-PGA volumetric productivity (approximately 0.12 gl-1 h-1) between 48 and 96 h; 11 g l-1 gamma-PGA volumetric yield by 96 h; reduction (utilization) of glycerol, glutamate and citrate during a 96 h cultivation time from 80 to 45 g l-1, 18 to 10 g l-1 and 12 to approximately 1 g l-1, respectively; a decrease in pH from 7.4 to approximately 5.5 by 42 h cultivation; acetic acid secretion into the medium at a maximum level of approximately 4.5 g l-1 and detection of the metabolite 2,3-butanediol (as acetoin) as a fermentation by-product at approximately 42 h and through a 96 h cultivation period. The presence of 2,3-butanediol indicated that the level of oxygen in the medium no longer supported a fully aerobic mode of metabolism. When the medium formulation was altered by removal of either citrate, L-glutamate or glycerol in shake flask experiments where pH was not controlled, 2.3, 9.0 and 4.0 g l-1, respectively, of gamma-PGA were formed. Variation of the medium ionic strength by the addition of up to 4% (w/v) NaCl led to the formation of gamma-PGA of relatively higher molecular weight but lower volumetric yield. Studies carried out on 5-day-old B. licheniformis cultures suggested that gamma-PGA depolymerase is intracellularly located or cell-bound. Culture filtrates showed no significant gamma-PGA depolymerase activity.
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PMID:Gamma-poly(glutamic acid) formation by Bacillus licheniformis 9945a: physiological and biochemical studies. 753 73

Bacillus licheniformis ATCC 9945A was cultivated in shake flasks using citrate (12 gl-1), glutamate (20 gl-1) and glycerol (80 gl-1) as carbon sources for cell growth and gamma-poly(glutamic acid) (gamma-PGA) production. The effect of the MnSO4 concentration in the medium over a range from 0.0 to 615 microns was studied. The number of viable cells increased for all concentrations of MnSO4 from approximately 10(5) to 10(9) colony-forming units (cfu) ml-1 by the early stationary phase (24 h). However, after 50 h, the cell viability decreased rapidly for relatively lower MnSO4 concentrations (0.615 and 0 microns). The utilization of carbon sources by B. licheniformis was greater for cultures containing 33.8 and 615 microns MnSO4 relative to cultures with no added MnSO4. For example, cultures with 615 microns MnSO4 utilized 37, 54 and 93% and cultures with no added MnSO4 utilized 19, 10 and 17% of glutamate, glycerol and citrate, respectively. The gamma-PGA volumetric yield increased from approximately 5 to 17 gl-1 for corresponding increases in MnSO4 concentration from 0 to 33.8 microns and then decreased at higher MnSO4 concentrations. The stereochemical content of gamma-PGA was found to vary inversely with MnSO4 concentration, and ranged from 59 to 10% L-glutamate units for MnSO4 concentrations of 0 and 615 microns, respectively. For all of the MnSO4 concentrations investigated, the gamma-PGA molecular weights decreased rapidly as the gamma-PGA volumetric yield simultaneously increased for cultivation times from 24 to approximately 50 h. Mw and Mn values after approximately 50 h cultivation times, determined by gel permeation chromatography (GPC), were 1.3 to 1.6 and 0.5 to 0.8 million g mol-1, respectively. A complex gamma-PGA molecular weight distribution that appeared bimodal by GPC analysis due to the presence of a low-molecular-weight product fraction was observed in cultures containing 33.8 and 61.5 microns MnSO4 at extended cultivation times. A high-molecular-weight fraction and the unfractionated gamma-PGA sample from the 33.8 microns MnSO4 culture contained 13 +/- 4 and 30 +/- 1% L-repeat units, respectively. A relationship between the product molecular weight and its stereochemical composition was thus established.
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PMID:Effects of manganese (II) on Bacillus licheniformis ATCC 9945A physiology and gamma-poly(glutamic acid) formation. 858 90

Bacillus licheniformis ATCC 9945a is one of the bacterial strains that produce gamma-poly(glutamic acid) (gamma-PGA). The use of carbohydrate medium components for gamma-PGA production was explored. Cells were grown in shake flasks or in controlled pH fermentors using medium formulations that contain different carbon sources. During the cultivations, aliquots were removed to monitor cell growth, carbon utilization, polymer production, and polymer molecular weight. Glucose was a better carbon source than glycerol for cell growth. Furthermore, glucose was utilized at a faster rate than glycerol, citrate, or glutamate. However, by using mixtures of glucose and glycerol in medium formulations, the efficiency of gamma-PGA production increased. For example, by increasing the glycerol in medium formulations from 0 to 40 g/L, the gamma-PGA broth concentration after 96 h increased from 5.7 to 20.5 g/L. Considering that glycerol utilization was low for the glucose/glycerol mixtures studied, it was unclear as to the mechanism by which glycerol leads to enhanced product formation. Cell growth and concomitant gamma-PGA production (12 g/L) at pH 6.5 was possible using glucose as a carbon source if trace amounts (0.5 g/L each) of citrate and glutamate were present in the medium. We suggested that citrate and glutamate were useful in preventing salt precipitation from the medium. In addition, glutamate may be preferred relative to ammonium chloride as a nitrogen source. The conversion of glucose to gamma-PGA by the strain ATCC 9945a was believed to occur by glycolysis of glucose to acetyl-CoA and tricarboxylic acid (TCA) cycle intermediates that were then metabolized via the TCA cycle to form alpha-ketoglutarate, which is a direct glutamate precursor.
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PMID:Effects of glucose and glycerol on gamma-poly(glutamic acid) formation by Bacillus licheniformis ATCC 9945a. 1009 19

Extensive spreading of liquid manure onto agricultural fields causes eutrophication of ground and surface water and also pollution of the atmosphere due to the high ammonium nitrogen content. A poly(gamma-glutamic acid) (PGA)-producing strain of Bacillus licheniformis was isolated in this study and investigated for its ability to reduce the ammonium nitrogen by converting ammonium into biomass and PGA as depot forms of nitrogen. In batch cultivations swine manure and an optimized mineral salts medium were used for PGA production. For example the cultivation of B. licheniformis strain S2 in liquid manure, which was modified by adding of 18 g citrate and 80 g glycerol l(-1) and exhibited a carbon to nitrogen ratio of 15.5:1, led to severe reduction of the ammonium content from 2.83 to 0.1 g x l(-1) and to the production of 0.16 g PGA and 7.5 g cell dry mass l(-1) within 410 h. Approximately 28% (w/w) of the total nitrogen was converted into cellular biomass, whereas 0.1% (w/w) was used for the production of PGA. In addition, approximately 33% (w/v) of the original ammonium was lost by stripping.
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PMID:Conversion of the nitrogen content in liquid manure into biomass and polyglutamic acid by a newly isolated strain of Bacillus licheniformis. 1258 95

Polyesters derived from glycerol and serinol were prepared. These polyesters were designed to be potential surrogate polymers for poly(glycolic acid) (PGA) to extend the properties that aliphatic biomedical polyesters could encompass. The 1- and 2-substituted glycerol derived monomers were liquids and difficult to polymerize reproducibly. In contrast the N-substituted serinol monomers were solids and easy to prepare. Each of the four N-substituted serinol-diol monomers was polymerized in a parallel fashion with each of the four commercially available diacids to produce a small library of 16 polyesters. Glass transition and contact angle values were determined to ascertain structure-property correlations due to defined chemical changes in the polymer mainchain and pendent chain. A serinol-derived precursor polymer was also prepared.
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PMID:A biomedical library of serinol-derived polyesters. 1558 91

Bacteria in a biofilm are enmeshed in a self-synthesized extracellular polysaccharide matrix that holds the bacteria together in a mass and firmly attaches the bacterial mass to the underlying surface. A major component of the extracellular polysaccharide matrix in several phylogenetically diverse bacteria is PGA, a linear polymer of N-acetylglucosamine residues in beta(1,6)-linkage. PGA is produced by the Gram-negative periodontopathogen Actinobacillus actinomycetemcomitans as well as by the Gram-positive device-associated pathogen Staphylococcus epidermidis. We recently reported that A.actinomycetemcomitans produces a soluble glycoside hydrolase named dispersin B, which degrades PGA. Here, we present the crystal structure of dispersin B at 2.0A in complex with a glycerol and an acetate ion at the active site. The enzyme crystallizes in the orthorhombic space group C222(1) with cell dimensions a=41.02A, b=86.13A, c=185.77A. The core of the enzyme consists a (beta/alpha)(8) barrel topology similar to other beta-hexosaminidases but significant differences exist in the arrangement of loops hovering in the vicinity of the active site. The location and interactions of the glycerol and acetate moieties in conjunction with the sequence analysis suggest that dispersin B cleaves beta(1,6)-linked N-acetylglucosamine polymer using a catalytic machinery similar to other family 20 hexosaminidases which cleave beta(1,4)-linked N-acetylglucosamine residues.
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PMID:Structural analysis of dispersin B, a biofilm-releasing glycoside hydrolase from the periodontopathogen Actinobacillus actinomycetemcomitans. 1587 75

The extracellular matrix produced by Bacillus subtilis B-1, an environmental strain that forms robust floating biofilms, was purified, and determined to be composed predominantly of gamma-polyglutamate (gamma-PGA), with a molecular mass of over 1,000 kDa. Both biofilm formation and gamma-PGA production by B. subtilis B-1 increased with increasing Mn(2+) or glycerol concentration. gamma-PGA was produced in a growth-associated manner in standing culture, and floating biofilms were formed. However, gamma-PGA was produced in a non-growth-associated manner in shaking culture conditions. When B. subtilis B-1 was grown in a microaerated culture system, floating biofilm formation and gamma-PGA production were significantly retarded, suggesting that oxygen depletion is involved in the initial steps of floating biofilm formation in standing culture. Proteomic analysis of membrane proteins demonstrated that flagellin, oligopeptide permease and Vpr protease precursor were the major proteins produced by cells in a floating biofilm and a colony.
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PMID:Biofilm formation by a Bacillus subtilis strain that produces gamma-polyglutamate. 1694 74

A useful route for the development of antitumour therapies is by creating improved methods for delivering therapeutic agents to tumour cells or subcellular compartments and increasing retention of drugs within target cells. In this study, we have characterized nanoparticle (NP) uptake and metabolism by DAOY cells, a human medulloblastoma cell line. NPs were formed from a novel polymer, poly (glycerol-adipate) (PGA), containing Rhodamine B Isothiocyanate (RBITC) as a fluorescent marker. It was observed that the cellular uptake of NPs depends on the incubation time and the concentration of NPs in the culture medium. The studies of retention and metabolism of NPs within cells indicated that 1) faster degradation of NPs within cells compared with that in cell culture medium in vitro; 2) a small fraction of NPs were recycled back to the outside of cell, whereas most NPs entered endosomes and lysosomes; and 3) recycled NPs were re-taken up in the following 2 h incubation time. These studies thus suggested that PGA NPs could be used for localising therapeutic agents into cells, and could provide prolonged drug effects because of their long sustained release in physiological conditions and their rapid release when taken up into cells.
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PMID:Uptake and metabolism of novel biodegradable poly (glycerol-adipate) nanoparticles in DAOY monolayer. 1711 18


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