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PubMed1968

The disorganization of hepatic cell nucleoli induced by ethionine and its reversal by adenine.

The structure of nuclei and nucleoli of hepatic cells after short-term ethionine administration was investigated with the electron microscope. By 1(1/2) hr after the injection, a distinct alteration occurred in the nucleoli which was characterized by the appearance of electron-opaque masses in the nucleolonema. After 6-8 hr, the nucleoli showed partial fragmentation into small, dense masses. Large aggregates of interchromatinic granules appeared in the nucleoplasm. Condensation of chromatin became prominent in the nucleoplasm particularly along the nuclear membrane. By 12 hr almost complete fragmentation of nucleoli had occurred. The administration of adenine or methionine at 4 hr prevented the development of nucleolar changes. Also, adenine administration at 8 hr after ethionine completely reversed the nucleolar lesion by 12 hr. After methionine administration at 8 hr, many nucleoli showed incomplete reconstruction with many twisted ropelike structures when viewed 4 hr later. Identical structures were found when adenine was given at 8 hr, and animals were sacrificed 2 hr later. On the basis of this observation, the simplified structures of nucleoli found 2 hr after adenine or 4 hr after methionine appeared to be precursors of the nucleolonema. It is suggested that nucleoli show at least two basic reaction patterns to inhibitors of RNA synthesis, one typified by actinomycin D and one by ethionine.

Adenine↗
PubMed2001

Fate of prebiotic adenine.

Equilibrium adsorption isotherm data for the purine base adenine has been obtained on several prebiotically relevant minerals by frontal analysis using water as a mobile phase. Adenine is far displaced toward adsorption on pyrite (FeS2), quartz (SiO2), and pyrrhotite (FeS), but somewhat less for magnetite (Fe3O4) and forsterite (Mg2SiO4). The prebiotic prevalence of these minerals would have allowed them to act as a sink for adenine; removal from the aqueous phase would confer protection from hydrolysis as well, establishing a nonequilibrium thermodynamic framework for increased adenine synthesis. Our results provide evidence that adsorption phenomena may have been critical for the primordial genetic architecture.

Adenine↗
PubMed1986

Release of 5'-guanosine monophosphate and adenine by Brucella abortus and their role in the intracellular survival of the bacteria.

Brucella abortus releases two components (fractions 3b and 10) that inhibit the myeloperoxidase-H2O2-halide antibacterial system of bovine neutrophils by inhibiting degranulation. Fractions 3b and 10 were analyzed by high-performance liquid chromatography and thin-layer chromotography and compared with nucleotide and base standards. These investigations indicated that fraction 3b coeluted and comigrated with 5'-guanosine monophosphate (GMP), whereas fraction 10 coeluted and comigrated with adenine. We determined the biologic effects of GMP, adenine, and B. abortus fractions 3b and 10 on neutrophil functions. Iodination activity of neutrophils was inhibited to approximately 65% of control by GMP (0.04 mg/ml) and by fraction 3b (0.04 mg/ml). Iodination was also suppressed to approximately 80% of control by adenine (0.04 mg/ml) and by fraction 10 (0.04 mg/ml). These results suggest that B. abortus produces GMP and adenine and that these substances contribute to the intracellular survival of the bacteria.

Adenine↗
PubMed1987

Adenine specific DNA chemical sequencing reaction.

Reaction of DNA with K2PdCl4 at pH 2.0 followed by a piperidine workup produces specific cleavage at adenine (A) residues. Product analysis revealed the K2PdCl4 reaction involves selective depurination at adenine, affording an excision reaction analogous to the other chemical DNA sequencing reactions. Adenine residues methylated at the exocyclic amine (N6) react with lower efficiency than unmethylated adenine in an identical sequence. This simple protocol specific for A may be a useful addition to current chemical sequencing reactions.

Adenine↗
PubMed1999

Dimerization of the guanine-adenine repeat strands of DNA.

Jovin and co-workers have demonstrated that DNA strands containing guanine-adenine repeats generate a parallel-stranded homoduplex. Here we propose that the homoduplex is a dimer of the ordered single strand discovered by Fresco and co-workers at acid pH. The Fresco single strand is shown here to be stabilized in aqueous ethanol where adenine is not protonated. Furthermore, we demonstrate that the strands dimerize at higher salt concentrations without significantly changing their conformation, so that the dimerization is non-cooperative. Hence, the Jovin homoduplex can form through a non-cooperative dimerization of two cooperatively melting single strands. The available data indicate that the guanines stabilize the Fresco single strand whereas the adenines cause dimerization owing to their known intercalation or clustering tendency. The guanine-adenine repeat dimer seems to be a DNA analog of the leucine zipper causing dimerization of proteins.

Acids↗
PubMed1997

Transfusing red blood cells stored in citrate phosphate dextrose adenine-1 for 28 days fails to improve tissue oxygenation in rats.

OBJECTIVE: To determine whether the time that red blood cells are stored in citrate phosphate dextrose adenine-1 solution before transfusion alters the ability to improve tissue oxygenation. DESIGN: Prospective, randomized, controlled study. SETTING: University research institute laboratory. SUBJECTS: Male Sprague-Dawley rats (350 to 450 g). INTERVENTIONS: Twenty-four hours after randomization to sham laparotomy (n = 21) or cecal ligation and perforation (n = 16)1 supply-dependency of systemic oxygen uptake (VO2) was induced in rats by isovolemic hemodilution. Rats were then re-randomized to receive either rat red blood cells stored in citrate phosphate dextrose adenine-1 for 3 days ("fresh" n = 17) or rat red blood cells stored in citrate phosphate dextrose adenine-1 for 28 days ("old" n = 20). MEASUREMENTS AND MAIN RESULTS: Changes in systemic VO2 were measured for 90 mins to determine the efficiacy of the treatment. Statistical analysis included a fully factorial repeated-measures, generalized linear model. No significant interaction was found between cecal ligation and perforation or sham animals and transfusion with fresh or old red blood cells. However, comparing the combined groups of animals receiving either fresh or old red blood cells, we found that after the transfusion of old red blood cells, systemic VO2 was not significantly improved (after hemodilution 1.68 +/- 0.27 mL/100 g/min, after transfusion 1.86 +/- 0.17 mL/100 g/min; p > .05). In contrast, transfusion with fresh red blood cells acutely increased systemic VO2 (after hemodilution 1.62 +/- 0.06 mL/100 g/min, after transfusion 2.10 +/- 0.09 mL/100 g/min; p = .049). CONCLUSION: Storage of rat red blood cells for 28 days in citrate phosphate dextrose adenine-1 impaired their ability to improve tissue oxygenation when transfused into either control or septic rats placed into supply dependency of systemic VO2.

Adenine↗
PubMed1987

Nuclear magnetic resonance assessment of adenosine triphosphate (ATP) dynamics in ischemic mouse livers perfused with adenine and ribose.

Hepatic energy stores are essential to liver viability. We used a mouse liver perfusion model and MR spectroscopy to study the effect of adding two precursors of ATP (adenine and ribose) on ATP dynamics during ischemia and reperfusion. Using Krebs-Henseleit buffer with or without added adenine and ribose made little difference in the ATP decay rate during ischemia, but the recovery of ATP during reperfusion was more complete when adenine and ribose were added to the buffer. These findings suggest that the addition of the precursors of ATP, adenine and ribose, to perfusate after ischemia can accelerate and enhance ATP recovery.

Adenine↗
PubMed1988

Adenine nucleotide metabolism and its relation to organ viability in human liver transplantation.

The relationship between adenine nucleotide metabolism and ischemic damage was studied in human liver. Thirty transplanted grafts were divided into two groups according to their functional outcome. Cellular adenine nucleotide levels were assayed by high-performance liquid chromatography. During cold ischemia, the adenosine triphosphate (ATP) level was not correlated with graft function, but two grafts with low total adenine nucleotides (TAN) levels showed poor function after transplantation. After recirculation, the ATP level showed good recovery in grafts that functioned satisfactorily (n = 24, 5.47 +/- 1.51 mumol/g dry weight), but remained low in poorly functioning grafts (n = 6, 3.30 +/- 1.68 mumol/g dry weight) (P less than 0.01). The level of recovery of ATP was inversely related to the period of warm ischemia during implantation (P less than 0.01). Bile production, used as a parameter of initial function, was observed shortly after implantation in 17 of 24 grafts that functioned satisfactorily, but in only 1 of 6 poorly functioning grafts. It is concluded that loss of adenine nucleotides and lack of bile production during transplantation are good markers of damaged grafts in human liver transplantation.

Adenine Nucleotides↗
PubMed1989

Glycolytic support of adenine nucleotides in rat liver flush-preserved with UW or Collins' II. Importance of donor nutritional status.

Correlation of hepatocellular adenine nucleotides in donor liver with clinical posttransplant outcome has recently been reported. Our earlier work with rats has shown that pretreatment of donors with glucose effectively retards hepatocellular ATP losses in livers preserved in Collins' II solution through potentiation of their glycolytic capacity. The primary substrate--i.e., endogenous or exogenous glucose--was not identified. The current study was undertaken to compare the relative efficacy of the University of Wisconsin (UW) solution, which is devoid of glucose, with Collins' II in the support of adenine nucleotides through anaerobic glycolysis in flush-preserved rat liver. Adult rats were either pretreated with 25% dextrose or fasted prior to liver harvesting and preservation in either UW or Collins' II. Adenine nucleotide degradation and lactate production during preservation were assessed. For a given dietary pretreatment, losses of ATP and adenylate energy charge and lactate production were similar for UW- and Collins' II-preserved livers. Donor pretreatment with dextrose resulted in significantly higher ex vivo liver ATP, energy charge, and lactate regardless of the preservation solution. Salvageable nucleotide degradates were increased significantly in UW livers, presumably through the effects of allopurinol. These results demonstrate that effective support of adenine nucleotides by glycolysis in flush-preserved liver is independent of the presence of exogenous glucose but dependent upon the nutritional status of the donor prior to liver procurement.

Adenine Nucleotides↗
PubMed1993

Ruthenium red, ribose, and adenine enhance recovery of reperfused rat heart.

BACKGROUND: Postischemic cardiac failure may be associated with inadequate storage of myocardial adenosine triphosphate (ATP). ATP precursors were administered to resuscitate the postischemic myocardium. METHODS: Hearts isolated from male Wistar adult rats were perfused with Krebs-Henseleit buffer (pH, 7.40), subjected to 30 minutes of global ischemia at 36 degrees C, followed by 30 minutes of retrograde reperfusion with the postischemic intervention of ruthenium red (1 microM), ribose (1 mM), and adenine (1 mM). Multiple analysis of variance was used to compare means between groups (eight rats in each group). RESULTS: In comparison with the nonischemic group, the postischemic nontreated group had a decrease in the maximum rate of left ventricular pressure rise (+dP/dt, P < 0.0005) and level of myocardial ATP (P < 0.0005) but an increase in level of mitochondrial Ca2+ (P < 0.005). In comparison with the nontreated group, ribose and adenine had no effect on all the above-mentioned parameters, and ruthenium red elevated maximum left ventricular +dP/dt (P < 0.05) and reduced mitochondrial Ca2+ (P < 0.05) with no change in ATP (P > 0.05). However, ruthenium red with ribose and adenine achieved a significant increase in maximum left ventricular +dP/dt (P < 0.0005), ATP levels (P < 0.005), and a decrease in levels of mitochondrial Ca2+ (P < 0.005). CONCLUSION: Acute postischemic cardiac failure may be related to Ca2+ overload in mitochondria. Ruthenium red may reduce mitochondrial Ca2+ overload. Ruthenium red, ribose, and adenine in combination may be capable of enhancing the recovery of myocardial high-energy phosphates and mechanical function in the postischemic myocardium.

Adenine↗
PubMed1994

Adenine transport in Escherichia coli.

The purP gene for energized high-affinity adenine uptake in Escherichia coli is localized to a restriction fragment between tnaB and bglR. Comparison with DNA sequence data (Burland et al. 1993) indicates the involvement of the open-reading frame f445 (86003 < 84666). A non-energized transport route of lower affinity also occurs. The purP system is known to require metabolic removal of transported adenine which would diminish futile cycling by the two transport systems and toxicity by external adenine. Analysis of a conventional kinetic model for permeases suggests that internal adenine might inhibit transport sufficiently to account for the lack of accumulation.

Adenine↗
PubMed1984

Adenine phosphoribosyltransferase mutants in Saccharomyces cerevisiae.

Mutants of Saccharomyces cerevisiae deficient in adenine phosphoribosyltransferase (A-PRT, EC 2,4,2,7) have been isolated following selection for resistance to 8-azaadenine in a prototrophic strain carrying the ade4-su allele of the gene coding for amidophosphoribosyltransferase (EC 2,4,2,14). The mutants were recessive and defined a single gene, apt1. They did not excrete purine when combined with ade4+. The mutants appeared to retain some A-PRT activity in crude extracts, and strains of the genotype ade2 apt1 responded to both adenine and hypoxanthine. Mutants deficient in adenine aminohydrolase (EC 3,5,4,2) activity, aah1, and hypoxanthine:guanine phosphoribosyltransferase (EC 2,4,2,8) activity, hpt1, were used to synthesize the genotypes apt1 hpt1 aah+ and apt1 hpt+ aah1. The absence of A-PRT activity in strains with these genotypes confirmed the hypothesis that the residual A-PRT activity of apt1 mutants was due to adenine aminohydrolase and hypoxanthine:guanine phosphoribosyltransferase acting in concert.

Adenine Phosphoribosyltransferase↗
PubMed2000

A new family of high-affinity transporters for adenine, cytosine, and purine derivatives in Arabidopsis.

In many organisms, including plants, nucleic acid bases and derivatives such as caffeine are transported across the plasma membrane. Cytokinins, important hormones structurally related to adenine, are produced mainly in root apices, from where they are translocated to shoots to control a multitude of physiological processes. Complementation of a yeast mutant deficient in adenine uptake (fcy2) with an Arabidopsis cDNA expression library enabled the identification of a gene, AtPUP1 (for Arabidopsis thaliana purine permease1), belonging to a large gene family (AtPUP1 to AtPUP15) encoding a new class of small, integral membrane proteins. AtPUP1 transports adenine and cytosine with high affinity. Uptake is energy dependent, occurs against a concentration gradient, and is sensitive to protonophores, potentially indicating secondary active transport. Competition studies show that purine derivatives (e.g., hypoxanthine), phytohormones (e.g., zeatin and kinetin), and alkaloids (e.g., caffeine) are potent inhibitors of adenine and cytosine uptake. Inhibition by cytokinins is competitive (competitive inhibition constant K(i) = 20 to 35 microM), indicating that cytokinins are transported by this system. AtPUP1 is expressed in all organs except roots, indicating that the gene encodes an uptake system for root-derived nucleic acid base derivatives in shoots or that it exports nucleic acid base analogs from shoots by way of the phloem. The other family members may have different affinities for nucleic acid bases, perhaps functioning as transporters for nucleosides, nucleotides, and their derivatives.

Adenine↗
PubMed1991

Roles of DNA adenine methylation in controlling replication of the REPI replicon of plasmid pColV-K30.

DNA adenine methylation controls DNA replication of plasmids containing the prototypic REPI replicon by affecting protein recognition and by altering the helical stability of the origin. Denaturing gradient gel electrophoresis shows that adenine methylated origin DNA is more easily melted than unmethylated. However, because an added DNA adenine methylation (dam) site at the origin, whether in or out of phase with other helically aligned dam sites, actually prevents replication, we conclude that destabilization of the helix is not the exclusive function of adenine methylation in REPI replication. We find that the conformation and degree of methylation at the origin, features which are important for protein recognition, are essential for replication. In fact, RepI, a protein required for replication initiation at REPI replicons, contains a region homologous with a domain in proteins which specifically recognize and bind 5'-GATC-3'. We propose that the dam sites in the origin play a dual role: one is destabilization of the helix, and the other is protein recognition.

Adenine↗
PubMed1975

A clinical evaluation of citrate-phosphate-dextrose-adenine blood.

(1) Blood was stored in polyvinyl-chloride bags containing citrate-phosphate-dextrose (CPD) with adenine in a final concentration of 0.25 mM. (2) Red cell ATP was well maintained (greater than 70% of original) for 4 weeks in whole blood as well as in red cell concentrate (PCV 85 plus or minus 2%). After 5 weeks the ATP level was about 70% in whole blood and about 40% in red cell concentrate. (3) Red cell 2,3-diphosphoglycerate (DPG) was about 60% of the original after 2 weeks and about 30% after 3 weeks of storage when stored both as whole blood and as red cell concentrate. (4) The red cell 24-hour post-transfusion viability was about 80% after 4 weeks of storage both as whole blood and as red cell concentrate. After 5 weeks of storage the 24-hour viability was 78.7 plus or minus 3.5% in whole blood and 76.5 plus or minus 6.7% in red cell concentrate. (5) 820 patients received 3,238 units of CPD-adenine blood, and 761 patients serving as controls received 2,807 units of acid-citrate-dextrose (ACD) blood. The frequency of transfusion reactions was 3.5% for patients receiving CPD-adenine blood and 4.1% for the control group. (6) The maximum storage time was set at 5 weeks for the CPD-adenine blood and 3 weeks for the ACD blood. The longer preservation time decreased out-dating by at least 50%.

ABO Blood-Group System↗
PubMed1983

The effects of octylglucoside on the interactions of chloroplast coupling factor 1 (CF1) with adenine nucleotides.

The effects of octylglucoside (OcGlc) micelles, which stimulate a Mg-specific ATPase activity in chloroplast coupling factor 1 [Pick, U. and Bassilian, S. (1982) Biochemistry, 21, 6144-6152], on the interactions of the enzyme with adenine nucleotides have been studied. 1. OcGlc specifically accelerates the binding and the release of ADP but not of ATP or adenosine 5'[beta, gamma-imido]triphosphate (AdoPP[NH]P) from the tight-sites. The binding affinity for ADP and for ATP is only slightly decreased (twofold) by the detergent. ATP competitively inhibits the binding of ADP and vice versa in the presence or absence of OcGlc. 2.OcGlc-induced inactivation of CF1-ATPase is correlated with the release of bound nucleotides. In the absence of medium nucleotides ADP X CF1 is rapidly inactivated while ATP X CF1 and AdoPP[NH]P X CF1 are slowly inactivated by OcGlc in parallel with the release of bound nucleotide. In contrast, low concentrations of either ATP or ADP in the medium effectively protect against OcGlc inactivation while AdoPP[NH]P, whose binding to CF1 is inhibited by OcGlc, is ineffective even at millimolar concentrations. The results suggest that the occupancy of the tight-sites protects the enzyme against OcGlc-induced inactivation. 3. Mg ions specifically inhibit the release of bound ADP and the OcGlc-induced inactivation of CF1. High concentrations of medium ATP and ADP (K50 = 100 microM) also inhibit the OcGlc-induced release of bound nucleotides in an EDTA medium. In contrast, in the absence of OcGlc, medium ADP and ATP accelerate the release of bound adenine nucleotides. 4. Mg-ATP in the presence of OcGlc stimulates the release of bound ADP from CF1. Bound ATP is neither released nor hydrolyzed at the tight-sites under these conditions where medium ATP is rapidly hydrolyzed. Mg-ADP stimulates the release of bound ADP only in the presence of inorganic phosphate or of phosphate analogs, e.g. arsenate, pyrophosphate or selenate. 5. It is suggested that: (a) ATP and ADP bind to the same tight-sites, but OcGlc activation specifically accelerates the exchange of bound ADP at the site. (b) CF1 contains low affinity adenine nucleotide binding sites which may be the catalytical sites and which influence the tight-sites by cooperative interactions. (c) Mg-ATP in the presence of OcGlc induces a conformational change at the catalytical site which accelerates the release of ADP from the tight-site. The implications of these results to the role of adenine nucleotides in the regulation and mechanism of ATP hydrolysis by CF1 are discussed.

Adenine Nucleotides↗
PubMed1978

The effects of adenine nucleotides on cutaneous afferent nerve activity.

1 The activity produced by the adenine nucleotides adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) and by potassium, acetylcholine (ACh), 5-hydroxytryptamine (5-HT) and bradykinin when applied to an exposed blister base on the ear of anaesthetized rabbits or intra-arterially to anaesthetized cats was investigated in multiple strands dissected from the auricular-temporal and saphenous nerves of rabbits and cats, respectively. 2 In the rabbit preparation potassium and the adenine nucleotides produced activity in the nerve fibres. The effects of these substances were produced in comparable dose ranges; threshold effects being produced by potassium at a concentration of 13 mM and by ADP at a concentration of 4 mM. ACh, 5-HT and bradykinin were inactive at similar or higher concentrations. 3 In the cat preparation all the substances tested produced activity in the nerve fibres. The adenine nucleotides were comparatively less potent than ACh, 5-HT or bradykinin, but had greater potency than potassium. 4 It was concluded that the adenine nucleotides do possess effects on afferent nerve terminals or fibres and thus resemble other known algogenic substances such as potassium, ACh, 5-HT and bradykinin.

Acetylcholine↗
PubMed1994

In vitro studies of release of adenine nucleotides and adenosine from rat vascular endothelium in response to alpha 1-adrenoceptor stimulation.

1. Noradrenaline-induced release of endogenous adenine nucleotides (ATP, ADP, AMP) and adenosine from both rat caudal artery and thoracic aorta was characterized, using high-performance liquid chromatography with fluorescence detection. 2. Noradrenaline, in a concentration-dependent manner, increased the overflow of ATP and its metabolites from the caudal artery. The noradrenaline-induced release of adenine nucleotides and adenosine from the caudal artery was abolished by bunazosin, an alpha 1-adrenoceptor antagonist, but not by idazoxan, an alpha 2-adrenoceptor antagonist. Clonidine, an alpha 2-adrenoceptor agonist, contracted caudal artery smooth muscle but did not induce release of adenine nucleotides or adenosine. 3. Noradrenaline also significantly increased the overflow of ATP and its metabolites from the thoracic aorta in the rat; however, the amount of adenine nucleotides and adenosine released from the aorta was considerably less than that released from the caudal artery. 4. Noradrenaline significantly increased the overflow of ATP and its metabolites from cultured endothelial cells from the thoracic aorta and caudal artery. The amount released from the cultured endothelial cells from the thoracic aorta and caudal artery. The amount released from the cultured endothelial cells from the aorta was also much less than that from cultured endothelial cells from the caudal artery. In cultured smooth muscle cells from the caudal artery, a significant release of ATP or its metabolites was not observed. 5. These results suggest that there are vascular endothelial cells that are able to release ATP by an alpha 1-adrenoceptor-mediated mechanism, but that these cells are not homogeneously distributed in the vasculature.

Adenine Nucleotides↗