Presence Of DAP Research Articles

Polyamine, 1,3-diaminopropane, regulates defence responses on growth, gas exchange, PSII photochemistry and antioxidant system in wheat under arsenic toxicity

The metalloid arsenic (As) is extremely hazardous to all living organisms, including plants. Pollution with As is very detrimental to the photosynthetic machinery, cell division, energy generation, and redox status. In order to cope with stress, the use of growth regulators such as polyamines (PA), which strengthen the antioxidant system of plants, has become widespread in recent years. PAs can modulate the plant growth through basic mechanisms common to all living organisms, such as membrane stabilization, free radical scavenging, deoxyribonucleic acid (DNA), ribonucleic acid (RNA) and protein synthesis, enzyme activities and second messengers. However, the effect of 1,3- diaminopropane (Dap), which is a product of PA catabolism, is not clear enough in plants exposed to As toxicity. In the current study, the different concentrations of 1,3-diaminopropane (0.1, 0.5 and 1 mM Dap) were hydroponically treated to wheat (Triticum aestivum) under arsenic stress (100 μM As) and then relative growth rate (RGR), relative water content (RWC), proline content (Pro), gas exchange parameters, PSII photochemistry, chlorophyll fluorescence kinetics, antioxidant activity and lipid peroxidation were assessed. RGR, RWC, osmotic potential and Pro content decreased in As-applied plants. The inhibition of these parameters could be reversed by Dap treatments. Besides, Dap applications mitigated the As toxicity-induced suppression on chlorophyll fluorescence (Fv/Fm, Fv/Fo and Fo/Fm) and the performance of PSII photochemistry. As impaired the balance on antioxidant capacity by decreased activities of catalase (CAT), peroxidase (POX), glutathione peroxidase (GPX), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and the contents of ascorbate (AsA) and glutathione (GSH) and then lipid peroxidation (TBARS content) increased. In the presence of Dap under As stress, the plants exhibited an increase in superoxide dismutase (SOD), POX, and GPX. Dap treatments contributed to the maintenance of cellular redox state (AsA/DHA and GSH/GSSG) by regulating the activities/contents of enzyme/non-enzyme involved in the AsA-GSH cycle. After Dap applications against stress, ROS accumulation (H2O2 content) and lipid peroxidation (TBARS) were effectively reduced. The findings showed that by eliminating As-induced oxidative damage and protecting the biochemical processes of photosynthesis, Dap treatments have a substantial potential to give resistance to wheat.

Evaluation of the effect of peptidoglycan-constituting components on photocatalytic bactericidal sterilization.

Previous studies in our lab have shown that peptidoglycan (PG) enhances the photocatalytic bactericidal effect. Therefore, in this study, we focused on the PG-constituting components. The PG-constituting components were added to Mesoplasma florum with no cell wall, respectively, and their effects on photocatalytic sterilization were investigated. The PG-constituting components used were amino sugars, amino acids, L-Alanine-D-Glutamic Acid (L-Ala-D-Glu) dipeptide of diaminopimelic acid (DAP）-type crosslinking peptide, and Lysine (Lys）-type crosslinking peptide. We compared the survival rates of M. florum cells and PG-constituting components-added M. florum cells after 3 h of photocatalytic reaction. Consequently, the survival rates of the cells that were added N-acetylglucosamine (GlcNAc）, DAP, and L-Ala- D-Glu dipeptide were significantly lower than those of only the cells. Furthermore, the amounts of hydrogen peroxide (H2O2) generated by the photocatalytic reaction under the presence of these components were determined. The results showed that DAP, L-Ala- D-Glu dipeptide, and PG of DAP-type significantly increased the amount of H2O2 produced. From the above results, it is suggested that the presence of DAP and L-Ala- D-Glu dipeptide in the photocatalytic reaction boosts the production of H2O2 and enhances the bactericidal effect and that GlcNAc might produce reactive oxygen species other than H2O2.

Anodic dissolution of gold in a solution of 1,3-diaminopropane with the formation of a cathodic deposit and a colloidal solution of Au

The corrosion of a Au anode in a solution of 1,3-diaminopropane (DAP) is studied by means of gravimetry. It is found that the products of corrosion of Au electrode in galvanostatic conditions are reduced on a Pt cathode with the formation of either an electrolytic Au deposit or a colloidal solution of metallic Au, depending on the current strength. The kinetics of the dissolution of Au in the presence of DAP is investigated. The formation of a complex of Au with DAP is observed, and a structure for it is proposed.

PO-0757 Perinatal Factors In The Development Of Bronchopulmonary Dysplasia

<h3>Background and aims</h3> Aetiology of BPD is multifactorial with prenatal and postnatal factors being involved. First, we aimed to evaluate the association between chorioamnionitis and BPD. Secondly, the effect of other perinatal factors on the risk of developing BPD were analysed. <h3>Methods</h3> Retrospective analysis of all infants with GA &lt;32 weeks or BW &lt;1500 g. admitted into our hospital between 2002–2010. 120 patients who died before 36 weeks of PMA were excluded. <h3>Results</h3> The average GA was: 29,7 ± 3 s; 217/432 (50%) had any type of chorioamnionitis (histological or clínical); 75/432 (17.4%) met diagnostic criteria for BPD at 36 weeks. Univariate analysis: lower GA, any type of chorioamnionitis, DAP and duration of mechanical ventilation (MV) were associated with an increased risk of DBP (p &lt; 0.05). Multivariate analysis: administration of antenatal steroids or chorioamnionitis did not independently modify the risk of BPD. But adding both, the effect became statistically significant protective for BPD (OR 0.52, 95% CI 0.03 to 0.79). Days in MV is the only factor that independently increased the risk of BPD. Neither a lower GA nor the presence of PDA had significantance; but, the risk of BPD was higher in the presence of PDA and MV together: every day in MV increased the risk of BPD (OR 1.130, 95% CI1.001- 1.27). <h3>Conclusions</h3> Chorioamnionitis in coexistence with antenatal corticosteroids decreases the risk of BPD. Mechanical ventilation is the main risk factor for BPD. In the presenceof DAP, ventilation increases the risk of BPD.

Structural Basis for Preferential Recognition of Diaminopimelic Acid-type Peptidoglycan by a Subset of Peptidoglycan Recognition Proteins

Drosophila peptidoglycan recognition protein (PGRP)-LCx and -LCa are receptors that preferentially recognize meso-diaminopimelic acid (DAP)-type peptidoglycan (PGN) present in Gram-negative bacteria over lysine-type PGN of gram-positive bacteria and initiate the IMD signaling pathway, whereas PGRP-LE plays a synergistic role in this process of innate immune defense. How these receptors can distinguish the two types of PGN remains unclear. Here the structure of the PGRP domain of Drosophila PGRP-LE in complex with tracheal cytotoxin (TCT), the monomeric DAP-type PGN, reveals a buried ionic interaction between the unique carboxyl group of DAP and a previously unrecognized arginine residue. This arginine is conserved in the known DAP-type PGN-interacting PGRPs and contributes significantly to the affinity of the protein for the ligand. Unexpectedly, TCT induces infinite head-to-tail dimerization of PGRP-LE, in which the disaccharide moiety, but not the peptide stem, of TCT is positioned at the dimer interface. A sequence comparison suggests that TCT induces heterodimerization of the ectodomains of PGRP-LCx and -LCa in a closely analogous manner to prime the IMD signaling pathway, except that the heterodimer formation is nonperpetuating.

Autoignition and thermogravimetric analysis of forest species treated with fire retardants

Spontaneous ignition tests of various forest species were performed with a specifically designed apparatus. The forest species selected: Arbutus andrachne, Cistus incanus, Pinus brutia, Pinus halepensis, Cupressus sempervirens, Pistacia lentiscus, Abies cephalonica are very common in the Mediterranean region which is frequently devastated by forest fires. The same tests were performed in the presence of 20% (w/w) (NH 4) 2HPO 4 (DAP) and 20% (w/w) (NH 4) 2SO 4 (AS). The presence of DAP and AS prolonged the ignition delay time and this effect was more pronounced at low temperatures (i.e. <530 °C). The autoignition delay properties of forest fuels treated with retardants were related to thermal analysis data obtained by thermogravimetry in nitrogen atmosphere. It was determined that the fire retardants shift the DTG major weight loss peaks of fuel to lower temperatures and increase the pyrolysis mass residue.

The effect of (NH 4) 2HPO 4 and (NH 4) 2SO 4 on the spontaneous ignition properties of Pinus halepensis pine needles

The spontaneous ignitability of Pinus halepensis pine needles was evaluated. Fire points and times taken for irradiated fuels to be ignited were correlated, at given heat intensity, to the airflow around the specimen and the sample size. The tests showed that increase of the airflow rate above 1.5 l min −1 increased considerably the fire point values and ignition delay times. On the contrary, the sample size in the range investigated (0.2–1.0 g) showed a negligible effect on the ignition properties. The influence of fire chemical retardants (NH 4) 2HPO 4 (DAP) and (NH 4) 2SO 4 (AS) on the ignitability characteristics was studied under various concentration levels. The data in this study showed that the presence of DAP and AS increases the fire point, as well as the time required for ignition, and this effect is pronounced at high concentration levels. However, at lower temperatures, i.e. below 500°C, flaming combustion appears sensitive to the AS quantity applied, whereas at high temperatures (i.e. above 600°C) the DAP concentration had a major influence on its flammability behavior. In addition the time of combustion was slightly extended, therefore, the energy release rate was reduced in the presence of fire retardants, particularly of AS. The purpose of this study was to quantify the fire extinguishing capabilities of (NH 4) 2HPO 4 and (NH 4) 2SO 4, commonly used chemicals in forest fires, by comparing the ignition properties of samples, prior and after retardant loading.

A High-Performance Liquid Chromatography Method for the Detection of Diaminopimelic Acid in Urine

We describe a quantitative assay for diaminopimelic acid (DAP) in urine. It involves (i) hydrolysis of urine samples, (ii) purification by several different liquid chromatography steps, and (iii) analysis by high-performance liquid chromatography on a reversed-phase C18 column. Tritiated-DAP, the internal standard, allows one to precisely follow the DAP-containing fractions and to determine the yield during purification. Sensitive and relatively accurate quantification of DAP, with a threshold of 50 fmol, is based on ion-pairing properties of eluants and ortho-phthaldialdehyde derivatization. The presence of DAP in relevant fractions was confirmed by combined gas chromatography and mass spectrometry. The DAP concentration in adult human urine pooled over 24 h ranges from 0.69 to 2.01 μM, a result in fair agreement with previously published values obtained by ninhydrin derivatization or gas chromatography.

Crystal Structure of an Ionic Charge-Transfer Complex of DAP-F4TCNQ (DAP = 1,6-Diaminopyrene, F4TCNQ = 2,3,5,6-Tetrafluoro-7,7,8,8-tetracyano-p-quinodimethane)

Abstract A charge-transfer complex of DAP with F4TCNQ has been obtained by electrochemical reduction of F4TCNQ in acetonitrile in the presence of DAP·BF4. The crystal comprises segregated one-dimensional columns of donors and acceptors with CH3CN as the crystal solvent. The molecular geometry and infrared spectrum show that the donor and acceptor components are completely ionized. These features are the same as those found in DAP·TCNQ. However, a marked difference lies in the column structure; both the DAP and F4TCNQ columns are composed of the dimerized units, while they are uniform in DAP·TCNQ. The difference can be accounted by the increase of the transfer energy in DAP·F4TCNQ·CH3CN compared with DAP·TCNQ.

Role of purine metabolism in thidiazuron‐induced somatic embryogenesis of geranium (Pelargonium×hortorum) hypocotyl cultures

Somatic embryogenesis in geranium (Pelargonium×hortorum Bailey cv. Scarlet Orbit Improved) was achieved by culturing hypocotyl sections on Murashige and Skoog (1962) (MS) medium containing 10 μM thidiazuron (TDZ) (induction medium) for 3 days and subsequently transferring the sections onto a basal medium lacking any plant growth regulators (expression medium). Addition of the purine analogue 2.6‐diaminopurine (DAP) to the somatic embryo induction medium completely inhibited the embryogenic response as well as chlorophyll accumulation without affecting enlargement of the treated tissues. Addition of 20 μM adenine sulphate to the expression medium, i.e during embryo growth and development phase, completely reversed the DAP‐induced inhibition of the embryogenic response while addition during the induction phase caused only a 50% reversal of the inhibition. Analysis of endogenous levels of plant growth substances indicated that TDZ alone elevated the levels of auxins, cy‐tokinins and abscisic acid while the presence of DAP during the induction phase caused a further increase in the levels of adenine and adenosine. These findings indicate a possible critical role for purines in embryogenesis from geranium hypocotyl tissues. However, the conversion of cytokinin bases to their corresponding nucleotide forms was not evident as the levels of isopentenyl adenine and zeatin increased during the second day of culture.

Suppression of c-myc oncogene expression by a polyamine-complexed triplex forming oligonucleotide in MCF-7 breast cancer cells.

Polyamines are excellent stabilizers of triplex DNA. Recent studies in our laboratory revealed a remarkable structural specificity of polyamines in the induction and stabilization of triplex DNA. 1,3-Diaminopropane (DAP) showed optimum efficacy amongst a series of synthetic diamines in stabilizing triplex DNA. To utilize the potential of this finding in developing an anti-gene strategy for breast cancer, we treated MCF-7 cells with a 37mer oligonucleotide to form triplex DNA in the up-stream regulatory region of the c-myc oncogene in the presence of DAP. As individual agents, the oligonucleotide and DAP did not downregulate c-myc mRNA in the presence of estradiol. Complexation of the oligonucleotide with 2 mM DAP reduced c-myc mRNA signal by 65% at 10 microM oligonucleotide concentration. In contrast, a control oligonucleotide had no significant effect on c-myc mRNA. The expression of c-fos oncogene was not significantly altered by the triplex forming oligonucleotide (TFO). DAP was internalized within 1 h of treatment; however, it had no significant effect on the level of natural polyamines. These data indicate that selective utilization of synthetic polyamines and TFOs might be an important strategy to develop anti-gene-based therapeutic modalities for breast cancer.

Facilitation by 3,4‐diaminopyridine of regenerative acetylcholine release from mouse motor nerve

1. Effects of 3,4-diaminopyridine (DAP) on endplate potentials (e.p.ps) were studied in mouse phrenic nerve-hemidiaphragms. 2. In cut muscle preparations, low concentrations of DAP (2-20 microns) increased the amplitude of e.p.ps and shifted the curve relating Ca2+ concentration to e.p.p. amplitude leftward. 3. High concentration of DAP (40-4000 microns) prolonged the duration of e.p.ps dose-dependently up to one hundred fold (ca. 200 ms), yielding, in addition to the normal phasic e.p.p., a prolonged plateau depolarization component which was often preceded by an upstroke depolarization. During the plateau depolarization, nerve stimulations did not evoke any e.p.p. 4. The plateau component of prolonged e.p.ps was suppressed by tubocurarine, verapamil, nifedipine, Mn2+ and Cd2+ (but not by atropine) at low concentrations that had negligible effect on the amplitude of miniature e.p.ps or the phasic component of e.p.ps. Abolition of the plateau component by these agents restored the capability of the nerve terminal to evoke e.p.ps on nerve stimulation. 5. Low concentrations of neostigmine (0.01-0.02 microns) markedly lengthened DAP-prolonged e.p.ps. However, the regenerative endplate depolarization evoked in the presence of high concentrations of neostigmine (0.3-0.5 microns) was not prolonged by DAP. 6. Tetraethylammonium (1 mM) did not provoke prolonged e.p.ps but acted cooperatively with DAP to prolong the duration of plateau depolarization. At a high concentration (3 mM), tetraethylammonium depressed the amplitude of miniature e.p.ps and abolished DAP-prolonged e.p.ps. 7. In uncut muscle preparations, DAP apparently did not modify the time course and amplitude of miniature e.p.ps. Upon direct stimulation by current injection at endplate, DAP increased the muscle action potentials by only about 30%, but induced no prolonged depolarization. 8. These results suggest that the prolonged e.p.ps induced in the presence of DAP are due to a regenerative release of acetylcholine from motor nerve and the induction probably involves a presynaptic Ca2+ channel different from that for normal e.p.ps. It may be inferred that the regenerative acetylcholine release is recruited by Ca2 + channels modulated by nicotinic receptors and K+ channels.

The reactivity of p-nitrophenyl esters with surfactants in apolar solvents. V. p-Nitrophenyl acetate in benzene solutions of butane-1,4-diamine bis(dodecanoate)

The rate of decomposition of p-nitrophenyl acetate in benzene in the presence of butane-1,4-diamine bis(dodecanoate) (budb) has been measured at temperatures between 333 and 353 K. The data fit a rate equation which consists of a term arising from micellar catalysis and a term arising from a bimolecular reaction between the ester and the components of budb. Arrhenius parameters have been estimated for the two reaction modes and compared with newly extended data for the similar reaction with dodecylammonium propionate (dap). 13C n.m.r. analysis of the products from there action of p-nitrophenyl propionate in the presence of dap has revealed that the amide is formed by an aminolysis reaction. The decrease in reaction rate observed with increasing water concentration is interpreted in terms of a biphasic water environment.

The usefulness of the analytical electrofocusing in a thin-layer polyacrylamide gel (PAG) in the histochemistry of enzymes cleaving peptide bonds.

The usefulness of the analytical electrofocusing in a thin-layer polyacrylamide (PAG) plate is shown on the basis of experiments with 10%–20% homogenates of various rat, rabbit and human organs as well as in lysates of isolated human lymphocytes and leucocytes in 2% Triton X100. 0.1–0.3 μl of 12000 g supernatants were applied on LKB Ampholine PAG plates pH range 3.5–9.5 and subjected to electrofocusing. Afterwards portions of PAG plates were processed in optimized histochemical media for the demonstration of enzymes cleaving peptide bonds using various substrates. The same media were used in the histochemical detection of enzymes in sections on slides or semipermeable membranes. Electrofocused zymograms display species and organ differences. Ala-MNA, Leu-MNA and Met-MNA furnish similar zymograms. Bands obtained with Ala-MNA are most intense. Zymograms with Gly-Pro-MNA and Lys-Pro-MNA at pH 7.2 are not entirely identical. The majority of bands is more intense when Gly-Pro-MNA is used as the substrate and is due to the activity of DAP IV. The anodal band(s) focusing around pH 4.9 (rat) or 5.5 (man) is (are) much stronger with Lys-Pro-MNA and DAP II is responsible for it (them). Zymograms with His-Ser-MNA and Lys-Ser-MNA are similar. However, they differ form those revealed with Gly-Pro-MNA and Lys-Pro-MNA. Zymograms of lysates of leucocytes obtained with naphthol AS-D-chloroacetate and Ac-Ala-l-naphthyl ester are not identical showing that more than one enzyme is responsible for the bands. Results obtained with closely related substrates such as Ac-Ala-l-naphthyl ester and Ac-Met-l-naphtyl ester are not identical either. Zymograms of lysates of human lymphocytes revealed with Gly-Pro-MNA at pH 7.2 and Lys-Ala-MNA or Lys-Pro-MNA at pH 5.5 or 5.3 respectively show clearly the presence of DAP IV and DAP II in these cells. The analytical electrofocusing in PAG plates is a very useful tool in the histochemistry (and biochemistry) of enzymes cleaving peptide bonds. It helps very much in the evaluation of the substrate specificity, choosing of the discriminating substrate and enables a quick and reliable testing of the quality of various batches of commercially supplied substrates, diazonium salts and other reagents. The correlation of zymograms with the “in situ” pattern helps in the elucidation of the origin of individual bands in zymograms and suggests different molecular forms of peptidases in different localizations.