Endogenous Polyamines and Ethylene Biosynthesis in Relation to Germination of Osmoprimed Brassica napus Seeds under Salt Stress

Currently, seed priming is reported as an efficient and low-cost approach to increase crop yield, which could not only promote seed germination and improve plant growth state but also increase abiotic stress tolerance. Salinity represents one of the most significant abiotic stresses that alters multiple processes in plants. The accumulation of polyamines (PAs) in response to salt stress is one of the most remarkable plant metabolic responses. This paper examined the effect of osmopriming on endogenous polyamine metabolism at the germination and early seedling development of Brassica napus in relation to salinity tolerance. Free, conjugated and bound polyamines were analyzed, and changes in their accumulation were discussed with literature data. The most remarkable differences between the corresponding osmoprimed and unprimed seeds were visible in the free (spermine) and conjugated (putrescine, spermidine) fractions. The arginine decarboxylase pathway seems to be responsible for the accumulation of PAs in primed seeds. The obvious impact of seed priming on tyramine accumulation was also demonstrated. Moreover, the level of ethylene increased considerably in seedlings issued from primed seeds exposed to salt stress. It can be concluded that the polyamines are involved in creating the beneficial effect of osmopriming on germination and early growth of Brassica napus seedlings under saline conditions through moderate changes in their biosynthesis and accumulation.     

Reaction of amines with conjugated olefins using lithium naphthalenide in non-ethereal solvents

It was found that lithium naphthalenide can be prepared from metallic lithium cuttings and naphthalene in non-ethereal solvents, such as benzene–N,N,N′,N′-tetramethylethylenediamine (TMEDA) or benzene-N,N,N′,N′-tetramethyldiaminopropane (TMDAP), under ultrasonic irradiation. Secondary amines reacted with conjugated olefins, such as isoprene or myrcene, using lithium naphthalenide in such non-ethereal solvents to give allylic amines. The yields of products were higher than in the reaction using lithium naphthalenide in tetrahydrofuran. From diethylamine (I) and isoprene (II), a mixture of N,N-diethyl-3-methyl-2-butenylamine (IV) and N,N-diethyl-2-methyl-2-butenylamine (V) (IV:V = 79:21) was obtained in 77% yield, and from diethylamine (I) and myrcene (III), N,N-diethylgeranylamine (VI) and N,N-diethylnerylamine (VII) (VI:VII = 88:12) were produced in 72% yield. These terpenic amines, VI and VII, are used as starting compounds for the preparation of perfumery materials.     

Antioxidative effects of polyamines

The antioxidative effects of spermine, spermidine and putrescine were determined by measurement of primary and secondary oxidation products of polyunsaturated fatty acids, using gas and liquid chromatography as well as spectrophotometric recordings. It was demonstrated that polyamines inhibit the oxidation of polyunsaturated fatty acids,α-tocopherol and carotenoid pigments. Both linear and nonlinear dose/response relationships have been observed. The efficiency of a given polyamine was correlated with the number of amine groups in the molecule. Spermine was, thus, more efficient than spermidine, which in turn had a higher efficiency than putrescine. The relative antioxidative effect was as follows: spermine (100.0), spermidine (61.0), putrescine (23.0), ethoxyquin (27.6), ascorbyl palmitate (18.3), octyl gallate (7.9), tert butylhydroquinone (6.3), butylated hydroxyanisole (3.6) andα-tocopherol (3.4).     

Structure–property relationships in polyhydroxyurethanes produced from terephthaloyl dicyclocarbonate with various polyamines

This article focuses on the synthesis and characterization of polyhydroxyurethanes (PHUs) obtained from the reaction between bis[(2‐oxo‐1,3‐dioxolan‐4‐yl)methyl]benzene‐1,4‐dicarboxylate (DCter) and various diamines (aliphatic, cycloaliphatic and oligomeric) or polyamines (diethylenetriamine (DETA) and diethylenetetramine (TETA)). The temperature and time conditions associated with each step‐growth polyaddition were defined by rheological tests directly performed on the reactive mixture. The chemical structures of DCter‐based PHUs containing primary and secondary alcohol groups were characterized using Fourier transform infrared spectroscopy. Differential scanning calorimetry experiments were performed on the various PHUs in order to investigate the influence of the chemical structure of the amines on the thermal properties of the polymers. Two different kinds of PHUs were obtained. On the one hand, the use of diamines led to thermoplastic polymers with a glass transition temperature (T_g) ranging from 4 to 78 °C depending on the flexibility of the diamine involved in the reaction. The hierarchy based on PHU T_g could be verified using the Van Krevelen methodology. On the other hand, PHUs produced from polyamines TETA and DETA were found to be insoluble and infusible due to the creation of polymeric networks. The DCter–DETA polymer had a higher T_g revealing a probable difference in the reactivity of primary and secondary amine groups. Copyright © 2012 Society of Chemical Industry     

Effects of Vaccinium myrtillus on Spruce Regeneration: Testing the Notion of Coevolutionary Significance of Allelopathy

Failure of natural regeneration of conifers, such as subalpine spruce (Picea abies) and black spruce (Picea mariana), has been reported in the presence of dominant ericaceous understory plants of boreal forests of North America, Fino-Scandinavia, and northern Europe. Among other factors such as competition for light and nutrients, conifer regeneration failure has been attributed to allelopathic effects of the understory ericaceous plants. Rabotnov theorized that (the manifestation of) allelopathy is a result of long-term coevolution within established plant communities and that it may have maximum inhibitory effects on introduced species. Our objectives were to determine what components of the understory ericaceous plant, Vaccinium myrtillus, affect spruce regeneration and to test Rabotnov's hypothesis. Field experiments were complemented with laboratory studies in which seed germination and primary growth of the two spruces were used as response variables. We found that P. mariana was generally more affected than P. abies by V. myrtillus allelochemicals, both in field and in vitro experiments. Field germination of P. abies was only 2% and 3% in the undisturbed sowed plots and in Vaccinium-removed sowed plots, respectively, but P. marana did not germinate at all in these treatments. In humus-removed sowed plots, P. abies had 27% germination, while P. marian had only 15%. In a controlled experiment, P. mariana had the highest decrease in dry weight of primary root in the fresh leaf treatment of V. myrtillus (77%), followed by its leaf leachate (71%), humus (29%), and humus leachate (13%). The decreases in root dry weights of P. abies due to these treatments were 67, 47, 30, and 10%, respectively. Our results provide support for Rabotnov's hypothesis. It is possible that both V. myrtillus and Kalmia angustifolia, involved in the growth inhibition process of P. abies and P. mariana, respectively adopted similar "strategies" of allelopathic inhibition of conifers, by allocating a large part of their carbon pool to the production of secondary metabolites.     

Altered Brain Arginine Metabolism and Polyamine System in a P301S Tauopathy Mouse Model: A Time-Course Study

Altered arginine metabolism (including the polyamine system) has recently been implicated in the pathogenesis of tauopathies, characterised by hyperphosphorylated and aggregated microtubule-associated protein tau (MAPT) accumulation in the brain. The present study, for the first time, systematically determined the time-course of arginine metabolism changes in the MAPT P301S (PS19) mouse brain at 2, 4, 6, 8 and 12 months of age. The polyamines putrescine, spermidine and spermine are critically involved in microtubule assembly and stabilization. This study, therefore, further investigated how polyamine biosynthetic and catabolic enzymes changed in PS19 mice. There were general age-dependent increases of L-arginine, L-ornithine, putrescine and spermidine in the PS19 brain (particularly in the hippocampus and parahippocampal region). While this profile change clearly indicates a shift of arginine metabolism to favor polyamine production (a polyamine stress response), spermine levels were decreased or unchanged due to the upregulation of polyamine retro-conversion pathways. Our results further implicate altered arginine metabolism (particularly the polyamine system) in the pathogenesis of tauopathies. Given the role of the polyamines in microtubule assembly and stabilization, future research is required to understand the functional significance of the polyamine stress response and explore the preventive and/or therapeutic opportunities for tauopathies by targeting the polyamine system.     

Characterization of methyl‐substituted polyamides used for reverse osmosis membranes by positron annihilation lifetime spectroscopy and MD simulation

Three kinds of polyamides were synthesized from three diamines and 1,3,5‐benzenetricarbonyl trichloride (TMC). The diamines used were m‐phenylene diamine, N‐methyl‐m‐phenylenediamine, and N,N′‐dimethyl‐m‐phenylenediamine. The average free volume sizes of the polyamides were measured by positron annihilation lifetime spectroscopy (PALS), and the free volume fractions were evaluated by molecular dynamics (MD) simulations. The methyl substitution on amino groups of diamines brought about an increase in interstitial space of molecular chains of the polyamides. In addition, reverse osmosis (RO) membranes were prepared by interfacial polymerization from the three diamines and TMC. The increase in the degree of methyl‐substitution of diamines led to increased chlorine resistance and decreased salt rejections of the polyamide RO membranes. Thus, the methyl‐substitution of diamines significantly influenced membrane performance. The vacancy sizes and fractional volumes in polyamides evaluated by PALS measurement and MD simulation were well correlated with salt rejection of polyamide RO membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Polyamines Influence Mouse Sperm Channels Activity

Polyamines are ubiquitous polycationic compounds that are highly charged at physiological pH. While passing through the epididymis, sperm lose their capacity to synthesize the polyamines and, upon ejaculation, again come into contact with the polyamines contained in the seminal fluid, unleashing physiological events that improve sperm motility and capacitation. In the present work, we hypothesize about the influence of polyamines, namely, spermine, spermidine, and putrescine, on the activity of sperm channels, evaluating the intracellular concentrations of chloride [Cl⁻]i, calcium [Ca²⁺]i, sodium [Na⁺]i, potassium [K⁺]i, the membrane V_m, and pHi. The aim of this is to identify the possible regulatory mechanisms mediated by the polyamines on sperm-specific channels under capacitation and non-capacitation conditions. The results showed that the presence of polyamines did not directly influence the activity of calcium and chloride channels. However, the results suggested an interaction of polyamines with sodium and potassium channels, which may contribute to the membrane V_m during capacitation. In addition, alkalization of the pHi revealed the possible activation of sperm-specific Na⁺/H⁺ exchangers (NHEs) by the increased levels of cyclic AMP (cAMP), which were produced by soluble adenylate cyclase (sAC) and interact with the polyamines, evidence that is supported by in silico analysis.     

Polyamine Metabolism under Different Light Regimes in Wheat

Although the relationship between polyamines and photosynthesis has been investigated at several levels, the main aim of this experiment was to test light-intensity-dependent influence of polyamine metabolism with or without exogenous polyamines. First, the effect of the duration of the daily illumination, then the effects of different light intensities (50, 250, and 500 μmol m^–2 s^–1) on the polyamine metabolism at metabolite and gene expression levels were investigated. In the second experiment, polyamine treatments, namely putrescine, spermidine and spermine, were also applied. The different light quantities induced different changes in the polyamine metabolism. In the leaves, light distinctly induced the putrescine level and reduced the 1,3-diaminopropane content. Leaves and roots responded differently to the polyamine treatments. Polyamines improved photosynthesis under lower light conditions. Exogenous polyamine treatments influenced the polyamine metabolism differently under individual light regimes. The fine-tuning of the synthesis, back-conversion and terminal catabolism could be responsible for the observed different polyamine metabolism-modulating strategies, leading to successful adaptation to different light conditions.     

The Association between Spermidine/Spermine N1-Acetyltransferase (SSAT) and Human Malignancies

Spermidine/spermine N¹-acetyltransferase (SSAT) functions as a critical enzyme in maintaining the homeostasis of polyamines, including spermine, spermidine, and putrescine, in mammalian cells. SSAT is a catalytic enzyme that indirectly regulates cellular physiologies and pathways through interaction with endogenous and exogenous polyamines. Normally, SSAT exhibits only at a low cellular level, but upon tumorigenesis, the expression, protein level, and activities of SSAT are altered. The alterations induce cellular damages, including oxidative stress, cell cycle arrest, DNA dynamics, and proliferation by influencing cellular mechanisms and signaling pathways. The expression of SSAT has been reported in various studies to be altered in different cancers, and it has been correlated with tumor development and progression. Tumor grades and stages are associated with the expression levels of SSAT. SSAT can be utilized as a target for substrate binding, and excreted metabolites may be used as a novel cancer biomarker. There is also potential for SSAT to be developed as a therapeutic target. Polyamine analogs could increase SSAT expression and increase the cytotoxicity of chemotherapy to tumor cells. Drugs targeting polyamines and SSAT expression have the potential to be developed into new cancer treatments in the future.     

Nitrogen-Induced Changes in Phenolics of Vaccinium myrtillus—Implications for Interaction with a Parasitic Fungus

The effects of nitrogen (N) fertilization on the phenolic status of Vaccinium myrtillus leaves were studied to assess whether N amendment affects the potentially defensive phenolic metabolites in a way that could have consequences for the interaction with a parasitic fungus (Valdensia heterodoxa). Healthy (symptomless) and V. heterodoxa-infected leaves were collected from plants grown in the understorey of a boreal coniferous forest, where they received no additional N or either a moderate or a high dose of N fertilizer. Leaf samples were taken during a single growth season and analyzed for individual phenolics using HPLC. The effect of a moderate N dose on the concentration and content of phenolics was in most cases nonsignificant. In contrast, the high N dose resulted in pronounced effects. In healthy leaves, N fertilization reduced concentration of three of five individual phenolics. Moreover, fertilization with high dose of N accompanied by infection by V. heterodoxa often increased the concentration and content of phenolics as compared to unfertilized plants. Addition of N had no significant effect on the growth of the analyzed V. myrtillus leaves, and the N-induced variation in phenolic levels seemed to be due to changed rate of their production. The concentration and content of phenolic metabolites in healthy leaves collected from unfertilized plots fluctuated compound-specifically during the growth season, and the phenolic responses to N and infection showed temporal and compound-specific variations.     

Phosphorus‐containing epoxy resins: Thermal characterization

Three novel aromatic phosphorylated diamines, i.e., bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl} pyromellitamic acid (AP), 4,4′‐oxo bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AB) and 4,4′‐hexafluoroisopropylidene‐bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AF) were synthesized and characterized. These amines were prepared by solution condensation reaction of bis(3‐aminophenyl)methyl phosphine oxide (BAP) with 1,2,4,5‐benzenetetracarboxylic acid anhydride (P)/3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride (B)/4,4′‐(hexafluoroisopropylidene)diphthalic acid anhydride (F), respectively. The structural characterization of amines was done by elemental analysis, DSC, TGA, ¹H‐NMR, ¹³C‐NMR and FTIR. Amine equivalent weight was determined by the acetylation method. Curing of DGEBA in the presence of phosphorylated amines was studied by DSC and curing exotherm was in the temperature range of 195–267°C, whereas with conventional amine 4,4′‐diamino diphenyl sulphone (D) a broad exotherm in temperature range of 180–310°C was observed. Curing of DGEBA with a mixture of phosphorylated amines and D, resulted in a decrease in characteristic curing temperatures. The effect of phosphorus content on the char residue and thermal stability of epoxy resin cured isothermally in the presence of these amines was evaluated in nitrogen atmosphere. Char residue increased significantly with an increase in the phosphorus content of epoxy network. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2235–2242, 2002     

Aromatic polyoxyalkylene amidoamines as curatives for epoxy resins — derivatives from t-butyl isophthalic acid

The condensation products of alkyl-substituted aromatic dicarboxylic acid and polyoxyalkylene polyamines were synthesized and used as epoxy curing agents. The novel amidoamines, prepared from t-butyl isophthalic acid (t-BuIPA) and polyoxyethylene diamines such as Jeffamine(R) EDR-148 and 192, exhibited fast cⁿring and good flexibility. Comparisons with other amidoamines derived from isophthalic and Dimer acid, and amines including Jeffamine(R) D-230, were made. The functionalities of alkyl and less hindered amines in the amidoamine structures affect the epoxy curing rate and material flexibility.Retired from Texaco Chemical Co., P. O. Box 15730, Austin, Texas 78761     

The role of amines as complexing agents in film growth during electropolymerization of ester substituted phenols onto mild steel

Electrolytic scouring required prior to the electrodeposition of non-polymerizable phenols onto an iron oxide layer at low potentials can be accelerated by the addition of polyamines as iron complexing agents. The scouring ability of NH₂(CH₂)_nNH₂ diamines increases asn increases. Monoamines display a general tendency to delay electropolymerization.     

Preparation of five-membered bis(cyclic carbonate)s at atmospheric pressure for polyhydroxyurethane coatings

Cyclic carbonates reacted with diamines or polyamines have been proposed as a greener and safer method to prepare free isocyanate polyurethane coatings. Here, five kinds of bis(cyclic carbonate)s (TDC: toluene bis(cyclic carbonate), MDC: 4,4′-diphenylmethane bis(cyclic carbonate), IPDC: isophorone bis(cyclic carbonate), HMDC: 4,4′-methylenebis(cyclohexyl cyclic carbonate), HDC: hexamethylene bis(cyclic carbonate)) were prepared by reacting glycerol carbonate with diisocyanate under atmospheric pressure. Their structures were verified by ¹H-NMR and ¹³C-NMR. These difunctional cyclic carbonates were then reacted with several amines to prepare new polyhydroxyurethane (PHU) coatings, and the film properties were tested. It was found that PHUs based on aromatic and alicyclic structures including TDC, MDC, IPDC, and HMDC displayed high hardness but had poor flexibility and impact resistance, whereas PHUs based on aliphatic structures such as HDC exhibited good flexibility and impact resistance and low hardness. When the length of the alkyl groups in the amine curing agents increased, the impact resistance and flexibility of the PHUs increased, but their pencil hardness decreased. PHUs from TDC, MDC, and IPDC had excellent chemical resistance, but the PHUs from HMDC and HDC had less chemical resistance. Some films displayed excellent properties including 4H pencil hardness, 100 cm kg impact resistance, and excellent flexibility. Some PHUs exhibited good thermal stability, with T_5% values all above 242°C. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47957.     

15N NMR spectroscopy as a method for comparing the rates of imidization of several diamines

The relative rates of the conversion of amide‐acid to imide were measured for a series or aromatic diamines that have been identified as potential replacements for 4,4′‐methylene dianiline (MDA) in high‐temperature polyimides and polymer composites. These rates were compared with the ¹⁵N NMR resonances of the unreacted amines. The initial rates of imidization track with the difference in chemical shift between the amine nitrogens in MDA and those in the subject diamines. This comparison demonstrated that ¹⁵N NMR spectroscopy is appropriate for the rapid screening of candidate diamines to determine their reactivity relative to MDA, and can serve to provide guidance to the process of creating the time–temperature profiles used in processing these materials into polymer matrix composites. POLYM. COMPOS. 27:723–729, 2006. © 2006 Society of Plastics Engineers     

The rate of ethylene polymerization initiated by various chelating tertiary diamine : n-butyllithium complexes

The initial rates of ethylene polymerization initiated by 13 chelating tertiary diamine:n-butyllithium complexes were determined under a standard set of conditions. Complexes of the cyclic diamines 1,2-dipyrrolidinoethane, sparteine, and 1,2-dipiperidinoethane resulted in higher polymerization rates and larger ultimate polymer yields than did complexes of acyclic diamines such as N,N,N′,N′-tetramethylethylenediamine. The rates of polymerization and also the polymer yields were also strongly affected by the length of the chain segment connecting the two amino groups in the diamine. Two carbon segments were superior to three carbon segments which were better than one or four carbon segments. The decomposition rate of n-butyllithium was also strongly accelerated by the presence of many of these diamines.     

Chiral Polyamino Alcohols via Hydroaminomethylation: A New Class of Polyamines for Dendritic Cores and Ligand Precursors

In this contribution, the synthesis of a new class of chiral polyamino alcohols (PAA) via a two‐step hydroaminomethylation/hydrolysis procedure is reported. The chiral polyamines are obtained by hydroaminomethylation of N‐olefinic oxazolidinones with different amines in first step followed by hydrolysis of the resulting polyamines to give the chiral PAA in the second step. The dendritic chiral PAA (Mw=1300–1400 g mol⁻¹) are also synthesized efficiently through a multifold hydroaminomethylation/hydrolysis procedure. Furthermore, chiral PAA are investigated as ligands in ruthenium‐catalyzed asymmetric hydrogen transfer reduction of acetophenone to 1‐phenyl alcohol.     

Green and Scalable Aldehyde‐Catalyzed Transition Metal‐Free Dehydrative N‐Alkylation of Amides and Amines with Alcohols

In contrast to the borrowing hydrogen‐type N‐alkylation reactions, in which alcohols were activated by transition metal‐catalyzed anaerobic dehydrogenation, the addition of external aldehydes was accidentally found to be a simple and effective protocol for alcohol activation. This interesting finding subsequently led to an efficient and green, practical and scalable aldehyde‐catalyzed transition metal‐free dehydrative N‐alkylation method for a variety of amides, amines, and alcohols. Mechanistic studies revealed that this reaction most possibly proceeds via a simple but interesting transition metal‐free relay race mechanism.