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Arabidopsis thaliana polyamine oxidase 5 gene (AtPAO5) functions as a thermospermine (T-Spm) oxidase. Aerial growth of its knock-out mutant (Atpao5-2) was significantly repressed by low dose(s) of T-Spm but not by other polyamines. To figure out the underlying mechanism, massive analysis of 3′-cDNA ends was performed. Low dose of T-Spm treatment modulates more than two fold expression 1,398 genes in WT compared to 3186 genes in Atpao5-2. Cell wall, lipid and secondary metabolisms were dramatically affected in low dose T-Spm-treated Atpao5-2, in comparison to other pathways such as TCA cycle-, amino acid- metabolisms and photosynthesis. The cell wall pectin metabolism, cell wall proteins and degradation process were highly modulated. Intriguingly Fe-deficiency responsive genes and drought stress-induced genes were also up-regulated, suggesting the importance of thermospermi′ne flux on regulation of gene network. Histological observation showed that the vascular system of the joint part between stem and leaves was structurally dissociated, indicating its involvement in vascular maintenance. Endogenous increase in T-Spm and reduction in H(2)O(2) contents were found in mutant grown in T-Spm containing media. The results indicate that T-Spm homeostasis by a fine tuned balance of its synthesis and catabolism is important for maintaining gene regulation network and the vascular system in plants.

An extreme thermophile, Thermus thermophilus grows at an optimum temperature of around 70°C and produces 16 different polyamines including long-chain and branched-chain polyamines. We found that the composition of polyamines in the thermophile cells changes with culture temperature. Long-chain and branched-chain polyamines (unusual polyamines) were increased in the cells grown at high temperature such as 80°C, but they were minor components in the cells grown at relatively lower temperature such as 60°C. The effects of polyamines on cell growth were studied using T. thermophilus HB8 ΔspeA deficient in arginine decarboxylase. Cell growth of this mutant strain was significantly decreased at 70°C. This mutant strain cannot produce polyamines and grows poorly at 75°C. It was also determined whether polyamines are directly involved in protecting DNA from DNA double-strand breaks (DSBs) induced by heat. Polyamines protected DNA against double-strand breaks. Therefore, polyamines play essential roles in cell growth at extremely high temperature through maintaining a functional conformation of DNA against DSBs and depurination.

Chiral chromatography is a sensitive technique used to separate l- and d-amino acids. Marfey’s reagent (1-fluoro-2,4-dinitrophenyl-5-l-alaninamide, FDAA) has been used as a chiral derivatization reagent to determine amino acid stereochemistry. Replacement of alanylamide in this reagent with leucylamide resulted in the derivative 1-fluoro-2,4-dinitrophenyl-5-l-leucinamide (FDLA), which proved a superior chiral derivatization reagent for the separation of d,l-amino acids due to the improved LC/MS measurement sensitivity. However, FDLA derivatization requires alkaline conditions, achieved with the use of NaHCO3, which necessitates an additional desalting step (e.g., liquid–liquid extraction) before quantitative analysis using LC/MS/MS. To establish a simplified LC/MS/MS measurement method, solid NaHCO3 was replaced with volatile triethylamine (TEA). The 30-min derivatization using FDLA under alkaline conditions with TEA at room temperature allowed for exclusion of the desalting step from the FDLA pre-column derivatization. Furthermore, using TEA, larger peak areas and more effective detection of hydrophilic amino acids could be achieved.

Branched-chain polyamine synthase (BpsA) catalyzes sequential aminopropyl transfer from the donor, decarboxylated S-adenosylmethionine (dcSAM), to the acceptor, linear-chain polyamine, resulting in the production of a quaternary-branched polyamine via tertiary branched polyamine intermediates. Here, we analyzed the catalytic properties and X-ray crystal structure of Tth-BpsA from Thermus thermophilus and compared them with those of Tk-BpsA from Thermococcus kodakarensis, which revealed differences in acceptor substrate specificity and C-terminal structure between these two enzymes. To investigate the role of the C-terminal flexible region in acceptor recognition, a region (QDEEATTY) in Tth-BpsA was replaced with that in Tk-BpsA (YDDEESSTT) to create chimeric Tth-BpsA C9, which showed a severe reduction in catalytic efficiency toward N4 -aminopropylnorspermidine, but not toward N4 -aminopropylspermidine, mimicking Tk-BpsA substrate specificity. Tth-BpsA C9 Tyr346 and Thr354 contributed to discrimination between tertiary branched-chain polyamine substrates, suggesting that the C-terminal region of BpsA recognizes acceptor substrates. Liquid chromatography-tandem mass spectrometry analysis on a Tk-BpsA reaction mixture with dcSAM revealed two aminopropyl groups bound to two of five aspartate/glutamate residues (Glu339 , Asp342 , Asp343 , Glu344 , and Glu345 ) in the C-terminal flexible region. Mutating each of these five amino acid residues to asparagine/glutamine resulted in a slight decrease in activity. The quadruple mutant D342N/D343N/E344Q/E345Q exhibited a severe reduction in catalytic efficiency, suggesting that these aspartate/glutamate residues function to receive aminopropyl chains. In addition, the X-ray crystal structure of the Tk-BpsA ternary complex bound to N4 -bis(aminopropyl)spermidine revealed that Asp126 and Glu259 interacted with the aminopropyl moiety in N4 -aminopropylspermidine.

Polyamines (PAs) are implicated in developmental processes and stress responses of plants. Polyamine oxidases (PAOs), flavin adenine dinucleotide-dependent enzymes that function in PA catabolism, play a critical role. Even though PAO gene families of Arabidopsis and rice have been intensely characterized and their expression in response to developmental and environmental changes has been investigated, little is known about PAOs in tomato (Solanum lycopersicum). We found seven PAO genes in S. lycopersicum and named them SlPAO1∼7. Plant PAOs form four clades in phylogenetic analysis, of which SlPAO1 belongs to clade-I, SlPAO6 and SlPAO7 to clade-III, and the residual four (SlPAO2∼5) to clade-IV, while none belongs to clade-II. All the clade-IV members in tomato also retain the putative peroxisomal-targeting signals in their carboxy termini, suggesting their peroxisome localization. SlPAO1 to SlPAO5 genes consist of 10 exons and 9 introns, while SlPAO6 and SlPAO7 are intronless genes. To address the individual roles of SlPAOs, we analyzed their expression in various tissues and during flowering and fruit development. The expression of SlPAO2∼4 was constitutively high, while that of the other SlPAO members was relatively lower. We further analyzed the expressional changes of SlPAOs upon abiotic stresses, oxidative stresses, phytohormone application, and PA application. Based on the data obtained, we discuss the distinctive roles of SlPAOs.

Polyamines acid extracted from roots, stems, leaves, flower buds, flowers and seeds of eight Brassica crop plants (cabbage, broccoli, cauliflower, Komatsuna, Chingensai, turnip, Aburana and Seiyou-aburana) with or without clubroot disease were analyzed by high-performance liquid chromatography and gas chromatography. Endogenous concentrations of polyamines per wet weight of the organ were calculated. In cabbage, broccoli and Komatsuna clubroot galls, the levels of putrescine, spermidine and spermine were increased whereas the levels of agmatine levels were decreased after the infection with a protist, Plasmodiophora brassicae. The levels of 2-phenylethylamine and homospermidine found in the normal healthy roots were decreased in the clubroots. The thermospermine level in broccoli was higher in the sprout stem than in the sprout root or other organs. A high agmatine level was found in the healthy sprouts and flower buds of broccoli and cauliflower flower buds. Diaminopropane, cadaverine and norspermine were detected in some Brassica organs as a minor polyamine. The seeds of the eight Brassica plants were rich in spermine and spermidine.

Thermophiles are organisms that grow optimally at temperatures higher than 55 °C. They contain two types of unusual longer/branched-chain polyamines in addition to common polyamines such as spermidine and putrescine. These unusual polyamines contribute to the survival of hyperthermophiles at high temperatures. Recently, the novel aminopropyltransferase BpsA was found to be responsible for the biosynthesis of branched-chain polyamines in the hyperthermophilic archaeon Thermococcus kodakarensis, which contains N 4-bis(aminopropyl)spermidine as the major polyamine. This compound is synthesized by the sequential addition of decarboxylated S-adenosylmethionine (dcSAM) aminopropyl groups to spermidine via the bifunctional catalytic action of BpsA. In this chapter, methods for the extraction and identification of branched-chain polyamines are presented, along with methods for the production and characterization of recombinant T. kodakarensis BpsA as a model aminopropyltransferase.

Long/branched-chain polyamines are unique polycations found in thermophiles. The hyperthermophilic archaeon Thermococcus kodakarensis contains spermidine and a branched-chain polyamine, N4-bis(aminopropyl)spermidine, as major polyamines. The metabolic pathways associated with branched-chain polyamines remain unknown. Here, we used gas chromatography and liquid chromatography-tandem mass spectrometry analyses to identify a new acetylated polyamine, N4-bis(aminopropyl)-N1-acetylspermidine, from T. kodakarensis; this polyamine was not found in other micro-organisms. The amounts of branched-chain polyamine and its acetylated form increased with temperature, indicating that branched-chain polyamines are important for growth at higher temperatures. The amount of quaternary acetylated polyamine produced was associated with the amount of N4-bis(aminopropyl)spermidine in the cell. The ratio of acetylated to non-acetylated forms was higher in the stationary phase than in the logarithmic growth phase under high-temperature stress condition.

Branched-chain polyamines are found exclusively in thermophilic bacteria and Euryarchaeota and play essential roles in survival at high temperatures. In the present study, kinetic analyses of a branched-chain polyamine synthase from the hyperthermophilic archaeon Thermococcus kodakarensis (Tk-BpsA) were conducted, showing that N4-bis(aminopropyl)spermidine was produced by sequential additions of decarboxylated S-adenosylmethionine (dcSAM) aminopropyl groups to spermidine, through bifunctional catalytic action. Tk-BpsA catalyzed the aminopropylation of the linear-chain polyamines spermidine, spermine, norspermidine, and the tertiary-branched polyamines N4-aminopropylspermidine and N4-aminopropylnorspermidine, but not of short-chain diamines, putrescine, and cadaverine, suggesting that Tk-BpsA does not catalyze the aminopropylation of primary amino groups of diamines. X-ray structural analyses of Tk-BpsA in the presence or absence of the substrates spermidine and dcSAM revealed that a large, negatively charged cavity is responsible for the binding of branched-chain substrates. The binding is different from that in the active site of linear polyamine spermidine/spermine synthases, and loop-closures occur upon the binding of spermidine. Based on structural analyses, further kinetic studies were carried out for various mutants, revealing that Asp159, positioned between the reactive secondary amino group of the substrate polyamine and a sulfur atom of the product 5ʹ-methylthioadenosine and in a Gly-Asp-Asp-Asp motif, functions as a catalytic center, with reactions proceeding via a ping-pong mechanism. Our study provides a novel aminopropyltransfer reaction mechanism, distinct from the SN2 displacement mechanism found in other known linear spermidine/spermine synthases. Database Atomic coordinates and structure factors have been deposited in the Protein Data Bank with PDB codes 5XNF for apo-Tk-BpsA, 5XNH for the binary complex, and 5XNC for the ternary complex.

The major plant polyamines (PAs) are the tetraamines spermine (Spm) and thermospermine (T-Spm), the triamine spermidine, and the diamine putrescine. PA homeostasis is governed by the balance between biosynthesis and catabolism; the latter is catalyzed by polyamine oxidase (PAO). Arabidopsis (Arabidopsis thaliana) has five PAO genes, AtPAO1 to AtPAO5, and all encoded proteins have been biochemically characterized. All AtPAO enzymes function in the back-conversion of tetraamine to triamine and/or triamine to diamine, albeit with different PA specificities. Here, we demonstrate that AtPAO5 loss-of-function mutants (pao5) contain 2-fold higher T-Spm levels and exhibit delayed transition from vegetative to reproductive growth compared with that of wild-type plants. Although the wild type and pao5 are indistinguishable at the early seedling stage, externally supplied low-dose T-Spm, but not other PAs, inhibits aerial growth of pao5 mutants in a dose-dependent manner. Introduction of wild-type AtPAO5 into pao5 mutants rescues growth and reduces the T-Spm content, demonstrating that AtPAO5 is a T-Spm oxidase. Recombinant AtPAO5 catalyzes the conversion of T-Spm and Spm to triamine spermidine in vitro. AtPAO5 specificity for T-Spm in planta may be explained by coexpression with T-Spm synthase but not with Spm synthase. The pao5 mutant lacking T-Spm oxidation and the acl5 mutant lacking T-Spm synthesis both exhibit growth defects. This study indicates a crucial role for T-Spm in plant growth and development.

Arabidopsis plants do not synthesize the polyamine cadaverine, a five carbon-chain diamine and structural analog of putrescine. Mutants defective in polyamine metabolic genes were exposed to exogenous cadaverine. Spermine-deficient spms mutant grew well while a T-DNA insertion mutant (pao4-1) of polyamine oxidase (PAO) 4 was severely inhibited in root growth compared to wild type (WT) or other pao loss-of-function mutants. To understand the molecular basis of this phenomenon, polyamine contents of WT, spms and pao4-1 plants treated with cadaverine were analyzed. Putrescine contents increased in all the three plants, and spermidine contents decreased in WT and pao4-1 but not in spms. Spermine contents increased in WT and pao4-1. As there were good correlations between putrescine (or spermine) contents and the degree of root growth inhibition, effects of exogenously added putrescine and spermine were examined. Spermine mimicked the original phenomenon, whereas high levels of putrescine evenly inhibited root growth, suggesting that cadaverine-induced spermine accumulation may explain the phenomenon. We also tested growth response of cadaverine-treated WT and pao4-1 plants to NaCl and found that spermine-accumulated pao4-1 plant was not NaCl tolerant. Based on the results, the effect of cadaverine on Arabidopsis growth and the role of PAO during NaCl stress are discussed.

Polyamine oxidase (PAO), which requires FAD as a cofactor, functions in polyamine catabolism. Plant PAOs are classified into two groups based on their reaction modes. The terminal catabolism (TC) reaction always produces 1,3-diaminopropane (DAP), H2O2, and the respective aldehydes, while the back-conversion (BC) reaction produces spermidine (Spd) from tetraamines, spermine (Spm) and thermospermine (T-Spm) and/or putrescine from Spd, along with 3-aminopropanal and H2O2. The Oryza sativa genome contains seven PAO-encoded genes termed OsPAO1-OsPAO7. To date, we have characterized four OsPAO genes. The products of these genes, i.e. OsPAO1, OsPAO3, OsPAO4 and OsPAO5, catalyze BC-type reactions. Whereas OsPAO1 remains in the cytoplasm, the other three PAOs localize to peroxisomes. Here, we examined OsPAO7 and its gene product. OsPAO7 shows high identity to maize ZmPAO1, the best characterized plant PAO having TC-type activity. OsPAO7 seems to remain in a peripheral layer of the plant cell with the aid of its predicted signal peptide and transmembrane domain. Recombinant OsPAO7 prefers Spm and Spd as substrates, and it produces DAP from both substrates in a time-dependent manner, indicating that OsPAO7 is the first TC-type enzyme identified in O. sativa. The results clearly show that two types of PAOs co-exist in O. sativa. Furthermore, OsPAO7 is specifically expressed in anthers, with an expressional peak at the bicellular pollen stage. The physiological function of OsPAO7 in anthers is discussed.

Oryza sativa polyamine oxidase 1 back-converts spermine (or thermospermine) to spermidine. Considering the previous work, major path of polyamine catabolism in rice plant is suggestive to be back-conversion but not terminal catabolism. Rice (Oryza sativa) contains seven genes encoding polyamine oxidases (PAOs), termed OsPAO1 to OsPAO7, based on their chromosomal number and gene ID number. We previously showed that three of these members, OsPAO3, OsPAO4 and OsPAO5, are abundantly expressed, that their products localize to peroxisomes and that they catalyze the polyamine back-conversion reaction. Here, we have focused on OsPAO1. The OsPAO1 gene product shares a high level of identity with those of Arabidopsis PAO5 and Brassica juncea PAO. Expression of OsPAO1 appears to be quite low under physiological conditions, but is markedly induced in rice roots by spermine (Spm) or T-Spm treatment. Consistent with the above finding, the recombinant OsPAO1 prefers T-Spm as a substrate at pH 6.0 and Spm at pH 8.5 and, in both cases, back-converts these tetraamines to spermidine, but not to putrescine. OsPAO1 localizes to the cytoplasm of onion epidermal cells. Differing in subcellular localization, four out of seven rice PAOs, OsPAO1, OsPAO3, OsPAO4 and OsPAO5, catalyze back-conversion reactions of PAs. Based on the results, we discuss the catabolic path(s) of PAs in rice plant.

Our work suggests that long chain polyamines and their derivatives are potential chemicals to control viral pathogens for crop production. Previously we showed that two tetraamines, spermine (Spm) and thermospermine (T-Spm), induce the expression of a subset of defense-related genes and repress proliferation of Cucumber mosaic virus (CMV) in Arabidopsis. Here we tested whether the longer uncommon polyamines (LUPAs) such as caldopentamine, caldohexamine, homocaldopentamine and homocaldohexamine have such the activity. LUPAs had higher gene induction activity than Spm and T-Spm. Interestingly the genes induced by LUPAs could be classified into two groups: the one group was most responsive to caldohexamine while the other one was most responsive to homocaldopentamine. In both the cases, the inducing activity was dose-dependent. LUPAs caused local cell death and repressed CMV multiplication more efficiently as compared to Spm. LUPAs inhibited the viral multiplication of not only avirulent CMV but also of virulent CMV in a dose-dependent manner. Furthermore, LUPAs can activate the systemic acquired resistance against CMV more efficiently as compared to Spm. When Arabidopsis leaves were incubated with LUPAs, the putative polyamine oxidase (PAO)-mediated catabolites were detected even though the conversion rate was very low. In addition, we found that LUPAs induced the expression of three NADPH oxidase genes (rbohC, rbohE and rbohH) among ten isoforms. Taken together, we propose that LUPAs activate two alternative reactive oxygen species evoked pathways, a PAO-mediated one and an NADPH-oxidase-mediated one, which lead to induce defense-related genes and restrict CMV multiplication.

It is known that the polyamine (PA) biosynthetic pathway is modulated at the transcriptional level during abiotic stresses. Here we studied the expression of PA biosynthetic pathway genes upon exposure to heat shock (HS) in Arabidopsis and showed that the spermine (Spm) synthase gene (SPMS) and S-adenosylmethionine decarboxylase 2 gene are induced at the earliest stage, followed by the induction of the arginine decarboxylase 2 gene. Correspondingly, Spm content increased linearly upon HS, and putrescine (Put) and spermidine (Spd) content also increased but not thermospermine (T-Spm) content. Exogenously applied Spm had a potential to protect Arabidopsis plants from HS-induced damage. Such protection was also observed to the same extent with T-Spm and by Spd to a lesser extent but not by Put. Then we tested whether altered endogenous Spm content affects sensitivity to HS using both transgenic plants overexpressing SPMS and a Spm deficient (spms) mutant plant. The result revealed that the higher the Spm content the higher the thermotolerance. Even in the spms plant, representative genes encoding heat shock proteins (HSPs) and heat shock transcription factors were upregulated upon HS, while the expression of such genes was increased in a positively correlated manner with Spm content. Furthermore four kinds of HSPs (HSP101, HSP90, HSP70 and HSP17.6) were detected proportionally with the levels of their respective transcripts upon HS. We propose that Spm increases the HS response at transcriptional and translational levels and protects host plants from HS-induced damage.

We previously proposed the defensive role of a signal pathway triggered by the polyamine spermine (Spm) in the reaction against avirulent viral pathogens in Nicotiana tabacum and Arabidopsis thaliana. In this study, we showed that thermospermine (T-Spm), an isomer of Spm, is also active in inducing the expression of the genes involved in the Spm-signal pathway at a similar dose as Spm. Furthermore, we found that T-Spm enhances the expression of a subset of pathogenesis-related genes whose expression is induced during cucumber mosaic virus (CMV)-triggered hypersensitive response. In consistent with the above observation, we further showed that exogenous T-Spm can repress CMV multiplication with same efficiency as Spm. Polyamine thermospermine, an isomer of spermine, is able to induce a subset of hypersensitive response-related defense genes and can suppress cucumber mosaic virus multiplication in Arabidopsis thaliana.

To maintain functional conformations of DNA and RNA in high-temperature environments, an extremely thermophilic bacterium, Thermus thermophilus, employs a unique polyamine biosynthetic pathway and produces more than 16 types of polyamines. In the thermophile genome, only one spermidine synthase homolog (SpeE) was found and it was shown to be a key enzyme in the pathway. The catalytic assay of the purified enzyme revealed that it utilizes triamines (norspermidine and spermidine) and agmatine as acceptors in its aminopropyl transfer reaction; therefore, the enzyme was denoted as a triamine/agmatine aminopropyltransferase (TAAPT). We determined the crystal structures of the enzyme complexed with and without the aminopropyl group donor S-adenosylmethionine. Despite sequence and structural similarity with spermidine synthases from other organisms, a novel C-terminal β-sheet and differences in the catalytic site were observed. The C-terminal module interacts with the gatekeeping loop and fixes the open conformation of the loop to recognize larger polyamine substrates such as agmatine and spermidine. Additional computational docking studies suggest that the structural differences of the catalytic site also contribute to recognition of the aminopropyl/aminobutyl or guanidium moiety of the substrates of TAAPT. These results explain in part the extraordinarily diverse polyamine spectrum found in T. thermophilus.

Arabidopsis thaliana was thought to contain two spermine synthase genes, ACAULIS 5 (ACL5) and SPMS. Recent investigations, however, revealed that the ACL5 gene encodes thermospermine synthase. In this study, we have established a simple method to separate two isomers of tetraamine, spermine and thermospermine, in extracts from plant tissues of less than 500 mg. Polyamines (PAs) extracted from plant tissues were benzoylated, and the derivatives were completely resolved by high-performance liquid chromatography on a C18 reverse-phase column, by eluting with 42% (v/v) acetonitrile in water in an isocratic manner at 30 °C and monitoring at 254 nm. The relevance of the method was confirmed by co-chromatography with respective PAs and by the PA analysis of the single- and double-mutants of acl5 and spms, which could not synthesize thermospermine and/or spermine, respectively. Furthermore, with this method, we monitored the thermospermine contents in various tissues of A. thaliana and found that stems and flowers contain two- to three-fold more thermospermine compared to whole seedlings and mature leaves. The presence of thermospermine was confirmed in Oryza sativa and Lycopersicon pesculentum. Finally we addressed whether salinity stress changes the contents of PAs including thermospermine in Arabidopsis.

The genome of Arabidopsis thaliana contains five genes (AtPAO1 to AtPAO5) encoding polyamine oxidase (PAO) which is an enzyme responsible for polyamine catabolism. To understand the individual roles of the five AtPAOs, here we characterized their tissue-specific and space-temporal expression. AtPAO1 seems to have a specific function in flower organ. AtPAO2 was expressed in shoot meristem and root tip of seedlings, and to a higher extent in the later growth stage within restricted parts of the organs, such as shoot meristem, leaf petiole and also in anther. The expression of AtPAO3 was constitutive, but highest in flower organ. AtPAO3 promoter activity was detected in cotyledon, distal portion of root, boundary region of mature rosette leaf and in filaments of flower. AtPAO4 was expressed at higher level all over young seedlings including roots, and in the mature stage its expression was ubiquitous with rather lower level in stem. AtPAO5 expression was observed in the whole plant body throughout various growth stages. Its highest expression was in flowers, particularly in sepals, but not in petals. Furthermore, we determined the substrate specificity of AtPAO1 to AtPAO4. None of the AtPAO enzymes recognized putrescine (Put). AtPAO2 and AtPAO3 showed almost similar substrate recognition patterns in which the most preferable substrate is spermidine (Spd) followed by less specificity to other tetraamines tested. AtPAO4 seemed to be spermine (Spm)-specific. More interestingly, AtPAO1 preferred thermospermine (T-Spm) and norspermine (NorSpm) to Spm, but did not recognize Spd. Based on the results, the individual function of AtPAOs is discussed.

The polyamines caldopentamine and homocaldopentamine were detected in axenic strains of Chattonella antiqua and Heterosigma akashiwo (Raphidophyceae), respectively, as well as spermidine, the most abundant polyamine in both phytoplankton species. Trace amounts of putrescine, diaminopropane and norspermine were also detected in both species. Spermine was detected only from C. antiqua. These long linear polyamines are characteristic components of thermophilic bacteria. The detection from two species of Raphidophyceae indicates that the occurrence of long linear polyamines is not restricted to thermophilic microorganisms.

The toxicity of acrolein was compared with that of reactive oxygen species using a mouse mammary carcinoma FM3A cell culture system. Complete inhibition of cell growth was accomplished with 10 microM acrolein, 100 microM H(2)O(2), and 20 microM H(2)O(2) plus 1mM vitamin C, which produce ()OH, suggesting that toxicity of acrolein is more severe than H(2)O(2) and nearly equal to that of ()OH, when these compounds were added extracellularly. Acrolein toxicity was prevented by N-acetyl-l-cysteine and N-benzylhydroxylamine, and attenuated by putrescine and spermidine. Toxicity of H(2)O(2) was prevented by glutathione peroxidase plus N-acetyl-l-cysteine, pyruvate, catalase, and reduced by polyphenol, and toxicity of ()OH was prevented by glutathione peroxidase plus N-acetyl-l-cysteine, pyruvate, catalase and reduced by N-acetyl-l-cysteine. The results indicate that prevention of cell toxicity by N-acetyl-l-cysteine was more effective with acrolein than with ()OH. Protein and DNA synthesis was damaged primarily by acrolein and reactive oxygen species, respectively.

Cellular polyamines of 25 newly validated thermophilic, acidophilic, alkaliphilic or radio-resistant bacteria (eubacteria) and 35 methanogenic, thermophilic or extremely halophilic archaea (archaebacteria) were analyzed by HPLC and GC. In the domain Bacteria, quaternary branched penta-amines, N4-bis(aminopropyl) norspermidine and/or N4-bis (aminopropyl)spermidine, were detected in the extreme thermophiles, Hydrogenovirga and Thermodesulfidibacter of the phylum Aquificae and Thermus of the phylum Thermus-Deinococcus. A liner penta-amine, homocaldopentamine, was found in moderately thermophilic Thermodesulfovibrio. Spermine, a tetra-amine, was found in the moderate thermophiles, Meiothermus, Exilispira, Desulfurispora, Desulfotomaculum, Caloramator and Calditerrivibrio but not in slightly thermophilc Thiofava and mesophilic radio-resistant Deinococcus. An acidophilic slight thermophile, Acidimicrobium, contained only cadaverine as a novel polyamine profile. The occurrence of spermine in mesophilic Acanthopleuribacter belonging to the phylum Acidobacteria was a unique profile. Alkaliphilic Alkalibacterium species were devoid of cellular polyamines. In the phylum Euryarchaeota of the domain Archaea, the branched penta-amines were distributed in the extremely thermophilic genera, Methanocaldococcus, Archaeoglobus and Thermococcus but not in hyperthermophilic Methanopyrus as well as in the mesophilic genera, Methanobacterium, Methanosaeta, Methanolobus, Methanocella and Methanofollis. Some methanogenic mesophiles contained spermine. Long and branched polyamines were not found in 23 extreme halophiles and halalkaliphiles belonging to the order Halobacteriales.

Cellular polyamines of 44 newly validated eubacterial thermophiles growing at 45-80°C, belonging to eight orders (six phyla) of the domain Bacteria, were analyzed by HPLC and GC. A quaternary branched penta-amine, N4-bis(aminopropyl)norspermidine, was found in Hydrogenivirga and Sulfurihydrogenibium belonging to the order of Aquificales. Another quaternary branched penta-amine, N4-bis(aminopropyl) spermidine, was detected in Thermovibrio, Desulfurobacterium (Aquificales), Moorella, Desul-fovirgula (Thermoanaerobacteriales), Thermaerobacter (Clostridiales), Caldalkalibacillus, Thermobacillus (Bacillales), and Desulfothermus (Desulfovibrionales of the phylum Proteobacteria). The two branched penta- amines as well as linear penta- and hexa-amines were produced by Thermus species of the order Thermales. Marinitoga and Fervidobacterium (Thermotogales) contained linear penta-amines. The production of these long polyamines was dependent on culture temperature and remarkable at 70-80°C in the extreme/ hyper-thermophiles and to alkaline medium pH 8.5-9.0 in moderately thermophilic bacilli. The long polyamines were not detected in moderately thermophilic Anaerolinea (Anaerolineales of the phylum Chloroflexi). Distribution of either or both long linear polyamines and/or quaternary branched polyamines in the extreme/hyper-thermophiles is also reflected in their phylogenetical evolved locations.

Two genes, LAT1 and OCT1 , are likely to be involved in polyamine transport in Arabidopsis. Endogenous spermine levels modulate their expression and determine the sensitivity to cadaverine. Arabidopsis spermine (Spm) synthase (SPMS) gene-deficient mutant was previously shown to be rather resistant to the diamine cadaverine (Cad). Furthermore, a mutant deficient in polyamine oxidase 4 gene, accumulating about twofold more of Spm than wild type plants, showed increased sensitivity to Cad. It suggests that endogenous Spm content determines growth responses to Cad in Arabidopsis thaliana. Here, we showed that Arabidopsis seedlings pretreated with Spm absorbs more Cad and has shorter root growth, and that the transgenic Arabidopsis plants overexpressing the SPMS gene are hypersensitive to Cad, further supporting the above idea. The transgenic Arabidopsis overexpressing L-Amino acid Transporter 1 (LAT1) absorbed more Cad and showed increased Cad sensitivity, suggesting that LAT1 functions as a Cad importer. Recently, other research group reported that Organic Cation Transporter 1 (OCT1) is a causal gene which determines the Cad sensitivity of various Arabidopsis accessions. Furthermore, their results suggested that OCT1 is involved in Cad efflux. Thus we monitored the expression of OCT1 and LAT1 during the above experiments. Based on the results, we proposed a model in which the level of Spm content modulates the expression of OCT1 and LAT1, and determines Cad sensitivity of Arabidopsis.

The translocation and metabolism of polyamines during soybean germination were studied using 15N-labelled putrescine as a precursor. Both 15N-labelled and unlabelled polyamines were simultaneously detected using a novel application of ionspray ionization-mass spectrometry. 15N-putrescine was rapidly transported to the shoots and roots, where it was converted to spermidine and spermine. The main 15N-polyamine that accumulated in the root was 15N-spermine. It was found that there were differences in the way endogenous putrescine and exogenous 15N-putrescine were metabolized in soybean seedlings.

In rat tissues, a decrease in spermidine, accompanied by an increase in spermine was induced by the oral administration (once daily for either 1 week or 1 month) of trans-4-methylcyclohexylamine (4MCHA), a spermidine synthase inhibitor. This is similar to the changes observed in polyamine content when cell growth is arrested. The body-weight gain of the rats tended to decrease with increasing doses of 4MCHA. A decrease in spermidine, combined with a moderate increase in spermine, was observed dose-dependently in all of the tissues tested, with a relatively fast clearance of 4MCHA. Manipulating the polyamine content of tissues, by daily administration of 100 mumol 4MCHA for 1 week, made it possible to estimate the effects of simultaneously added spermidine or spermine on endogenous polyamine contents. The altered polyamine levels, obtained after daily administration for 1 week, were maintained during the extended 1-month period, with growth-dependent alteration. The results show it is possible to produce experimental rats with a higher spermine:spermidine ratio than control rats to investigate the physiological significance of spermidine downregulation and spermine upregulation in vivo.

Polyamines extracted from whole bodies of four springtails, Tomocerus ishibashii , Hypogastrura communis , Sinella cruviseta and Folsomia candida , a bristletail, Pedetontus nipponicus , and two silverfish, Lepisma saccharina and Thermobia domestica , were analyzed by high-performance liquid chromatography and gas chromatography. All seven apterous insect species contained putrescine, cadaverine and spermidine as the common major polyamines, detected at the level of μmol/g wet mass. T. ishibashii also contained spermine, S. cruviseta contained norspermidine and norspermine and H. communis , F. candida and P. nipponicus contained diaminopropane, norspermidine and norspermine, as minor polyamines above the detection limit (0.01 μmol/g wet mass). The occurrence of diaminopropane, norspermidine, norspermine, spermine and thermospermine was confirmed in L. saccharina and T. domestica . The novel polyamines norspermidine, norspermine and thermospermine, widespread in higher insects, were also distributed within the primitive apterygotan insects.

A method for the simultaneous determination of polyamines (putrescine, spermidine, and spermine) by ionspray ionization-mass spectrometry was modified to determine (15)N-labeled polyamines together with unlabeled polyamines using (13)C,(15)N double-labeled polyamines as internal standards. This technique permitted the use of (15)N-labeled polyamines as tracer compounds to follow polyamine biosynthesis, interconversion, and absorption. The method was used to examine the organ distribution of orally administered (15)N-labeled polyamines in rats. Each (15)N-labeled polyamine was taken up by the three organs tested: the small intestine, liver, and kidney. The uptake of (15)N-labeled spermidine was greater than that of (15)N-labeled spermine and putrescine. Administration of a mixture of (15)N-labeled polyamines was useful for determining the disposition of each (15)N-polyamine absorbed from the intestinal tract.

Longer- and/or branched-chain polyamines are unique polycations found in thermophiles. N 4 -aminopropylspermine is considered a major polyamine in Thermococcus kodakarensis . To determine whether a quaternary branched penta-amine, N 4 -bis(aminopropyl)spermidine, an isomer of N 4 -aminopropylspermine, was also present, acid-extracted cytoplasmic polyamines were analyzed by high-pressure liquid chromatography, gas chromatography (HPLC), and gas chromatography-mass spectrometry. N 4 -bis(aminopropyl)spermidine was an abundant cytoplasmic polyamine in this species. To identify the enzyme that catalyzes N 4 -bis(aminopropyl)spermidine synthesis, the active fraction was concentrated from the cytoplasm and analyzed by linear ion trap–time of flight mass spectrometry with an electrospray ionization instrument after analysis by the MASCOT database. TK0545, TK0548, TK0967, and TK1691 were identified as candidate enzymes, and the corresponding genes were individually cloned and expressed in Escherichia coli . Recombinant forms were purified, and their N 4 -bis(aminopropyl)spermidine synthesis activity was measured. Of the four candidates, TK1691 (BpsA) was found to synthesize N 4 -bis(aminopropyl)spermidine from spermidine via N 4 -aminopropylspermidine. Compared to the wild type, the bpsA -disrupted strain DBP1 grew at 85°C with a slightly longer lag phase but was unable to grow at 93°C. HPLC analysis showed that both N 4 -aminopropylspermidine and N 4 -bis(aminopropyl)spermidine were absent from the DBP1 strain grown at 85°C, demonstrating that the branched-chain polyamine synthesized by BpsA is important for cell growth at 93°C. Sequence comparison to orthologs from various microorganisms indicated that BpsA differed from other known aminopropyltransferases that produce spermidine and spermine. BpsA orthologs were found only in thermophiles, both in archaea and bacteria, but were absent from mesophiles. These findings indicate that BpsA is a novel aminopropyltransferase essential for the synthesis of branched-chain polyamines, enabling thermophiles to grow in high-temperature environments.

Thermospermine, a structural isomer of spermine, is widely distributed in the plant kingdom and has been shown to play a role in repressing xylem differentiation by studies of its deficient mutant, acaulis5 (acl5), in Arabidopsis. Our results of microarray and real-time PCR analyses revealed that, in addition to a number of genes involved in xylem differentiation, genes related to auxin signaling were up-regulated in acl5 seedlings. These genes include MONOPTEROS, an auxin response factor gene, which acts as a master switch for auxin-dependent procambium formation, and its target genes. Their expression was reduced by exogenous treatment with thermospermine or by transgenic induction of the ACL5 gene. We examined the effect of synthetic polyamines on the expression of these auxin-related genes and on the vascular phenotype of acl5, and found that tetramines containing the NC3NC3N chain could mimic the effect of thermospermine but longer polyamines containing the same chain had little or no such effect. We also found that thermospermine had an inhibitory effect on lateral root formation in wild-type seedlings and it was mimicked by synthetic tetramines with the NC3NC3N chain. These results suggest the importance of the NC3NC3N chain of thermospermine in its action in modulating auxin signaling.

Acid-extractable cellular polyamines of thermophilic Caldisericum exile belonging to a new bacterial phylum, Caldiserica were analyzed by HPLC and GC. The coexistence of an unusual tertiary brancehed tetra-amine, N4-aminopropylspermidine with spermine, a linear tetra-amine, as the major polyamines in addition to putrescine and spermidine, is first reported in the moderate thermophile isolated from a terrestrial hot spring in Japan. Linear and branched penta-amines were not detected. The novel cellular polyamine profile found in the moderate thermophile has never been observed within various bacteria and archaea previously analyzed.

Four aquatic plants were tested for the occurrence of unusual polyamines by high performance liquid chromatography and gas chromatography. The whole plants ubiquitously contained norspermidine, homospermidine, norspermine, and thermospermine in addition to usual polyamines such as diaminopropane, putrescine, spermidine, and spermine. Pistia stratiotes L. and Potamogeton distinctus A. Bennett contained aminopropylhomospermidine. Caldopentamine was detected in the former plant. Homospermine was found in Ranuculus aquatilis L. Two tertiary branched tetraamines, N4-aminopropylnorspermidine and N4-aminopropylspermidine, were detected in Potamogeton distinctus and Sagittaria trifolia L.Key words: aquatic plant, polyamine, tertiary branched tetraamine.

We describe here an application of ionspray ionization-mass spectrometry (IS-MS) for simultaneous determination of putrescine, spermidine, and spermine without the need for coupling with other separation techniques such as high-performance liquid chromatography or capillary electrophoresis. Because it was essential to increase the mass of these compounds to eliminate contaminated low-mass ions, heptafluorobutyryl (HFB) derivatives were chosen. It was found that each HFB-polyamine appeared as a single major cation carrying an ammonium ion in a solution of 50% acetonitrile-water containing 0.5% ammonium acetate at an orifice potential of 20 V. Under these conditions, the three polyamines after addition of 15N-labeled polyamines as internal standards, followed by heptafluorobutylation, were determined simultaneously. It was shown, using a sample injection bulb set between the syringe drive and ionspray probe, that the analysis time for data acquisition was about 3 min and the sensitivity was about 10 fmol. In addition, polyamines in rat liver were determined by this method after simple fractionation with a small column of CM-cellulose with reasonable accuracy and precision. Behaviors of acetylated polyamines were also described, and the results showed that the acetylated polyamines would become additional target compounds in the present method.

Four aquatic plants were tested for the occurrence of unusual polyamines. The leaves of the aquatic plants tested ubiquitously contained homospermidine in addition to usual polyamines such as diaminopropane, putrescine, cadaverine, spermidine, spermine, and agmatine. Brasenia schreberi and Nuphar japonicum belonging to the family Nymphaeaceae contained aminopropylhomospermidine. Norspermidine and norspermine were detected in the blackweed Hydrilla verticillata belonging to Hydrocharitaceae. Thermospermine was detected in Brasenia schreberi. A novel tetraamine, N,N'-bis(3-aminopropyl)-1,2-ethanediamine (NH2(CH2)3NH(CH2)2NH(CH2)3NH2), was discovered in the aquatic plant Nuphar japonicum. This is the first report of the occurrence of N4-methylspermidine (NH2(CH2)3N(CH3)(CH2)4NH2) in the water chestnut Trapa natas belonging to the family Hydrocaryaceae. Key words: aquatic plants, polyamine, bis(aminopropyl)ethandiamine, methylspermidine.

Polyamines of the seeds, seedlings, and some other tissues of 15 leguminous plants were analyzed by high performance liquid chromatography and gas chromatography. A novel tertiary branched pentaamine, N5-aminobutylhomospermine, was detected in the seed of Vicia villosa and another novel quaternary branched pentaamine, N4-bis(aminopropyl)spermidine, in the seed of Crotalaria spectabilis. Norspermine and a novel linear pentaamine, caldopentamine, were found in the seed of Gleditschia japonica. Other unusual polyamines such as norspermidine, homospermidine, thermospermine, N4-methylthermospermine, homospermine, and N-(3-aminopropyl)aminopropanol occur widely within leguminous seeds. Nine groups of plant response were found with respect to increases of diaminopropane, putrescine, cadaverine, and agmatine in the leguminous seedlings after germination. Keywords: leguminae, seed, seedling, polyamine.

[5, 8-13C2]Spermine and [1, 12-13C2]spermine were prepared using [13C]KCN as the source of the label. By reaction of the latter with 1, 2-dibromoethane and ethylene chlorohydrin, the corresponding [1, 4-13C2]succinodinitrile and [CN-13C]ethylene cyanohydrin were respectively obtained. The reaction conditions were carefully adjusted so as to optimize the yields of the 13C-enriched intermediates. The nitrile residues were then reduced using sodium trifluoroacetoxyborohydride in tetrahydrofuran. [1, 4-13C2]Putrescine and [3-13C]3-aminopropanol were thus obtained. The latter was transformed into its [3-13C]3-carbobenzyloxyamidopropyl bromide derivative. The syntheses of [5, 8-13C2]spermine from the [1, 4-13C2]putrescine precursor and N-(3-bromopropyl)phthalimide, and of [1, 12-13C2]spermine from N, N'-bisbenzylputrescine and the [3-13C]3-carbobenzyloxyamidopropyl bromide precursor were then carried out using our previously reported methods, which were modified so as to maximize the yields of the 13C-enriched products.

Two unusual aminopropyl acceptors found in a survey of putrescine binding sites of mammalian spermidine synthase, N-methylputrescine (I) and 4-aminomethylpiperidine (II), were examined for their aminopropyl derivatives. Studies under in vitro incubation conditions suggested that the aminopropyl derivatives of the secondary amine of I and II, N4-methylspermidine (Is) and 1-N-(3-aminopropyl)-4-aminomethylpiperidine (IIs), and of the primary amine of I and II, N8-methylspermidine (Ip) and 4-[N-(3-aminopropyl)aminomethyl]piperidine (IIp), respectively, were biosynthesized by rat spermidine synthase. Studies on the cell culture system of cultured rat hepatoma (HTC) cells treated with alpha-difluoromethylornithine, an ornithine decarboxylase inhibitor, clearly showed the presence of Is and Ip when I was administered, and IIs and IIp when II was administered, with no detection of putrescine or spermidine. These results suggested that mammalian spermidine synthase can transfer the aminopropyl moiety of decarboxylated S-adenosylmethionine to certain secondary amines in living cells.

Polyamines such as spermidine (Spd) and spermine (Spm), produced by aminopropyltransferase (Apt), play roles in cell growth and differentiation. A sensitive and simple fluorometric high-performance liquid chromatographic determination for Apt activity of spermidine synthase (Spdsyn) and spermine synthase (Spmsyn) was developed in order to examine cellular functions of polyamine synthesis. The derivatization procedure for methylthioadenosine (MTA) produced from decarboxylated S-adenosylmethionine by Apt was the reaction with 2-chloroacetaldehyde to give fluorescent 1, N(6)-etheno methylthioadenosine. The reaction conditions for derivatization were optimized. A calibration curve was established, ranging from 0.01 to 25 pmol. Quantification of derivatized MTA was confirmed to be identical to Spd or Spm production. The developed method determined Spdsyn and Spmsyn activities in HepG2 cells treated with oleic acid as a cellular lipid accumulation model.

Polyamine oxidases (PAOs) are FAD-dependent enzymes involved in polyamine (PA) catabolism. Recent studies have revealed that plant PAOs are not only active in the terminal catabolism of PAs as demonstrated for maize apoplastic PAO but also in a polyamine back-conversion pathway as shown for most Arabidopsis PAOs. We have characterized Oryza sativa PAOs at molecular and biochemical levels. The rice genome contains 7 PAO isoforms that are termed OsPAO1 to OsPAO7. Of the seven PAOs, OsPAO3, OsPAO4, and OsPAO5 transcripts were most abundant in 2-week-old seedlings and mature plants, while OsPAO1, OsPAO2, OsPAO6, and OsPAO7 were expressed at very low levels with different tissue specificities. The more abundantly expressed PAOs—OsPAO3, OsPAO4, and OsPAO5—were cloned, and their gene products were produced in Escherichia coli. The enzymatic activities of the purified OsPAO3 to OsPAO5 proteins were examined. OsPAO3 favored spermidine (Spd) as substrate followed by thermospermine (T-Spm) and spermine (Spm) and showed a full PA back-conversion activity. OsPAO4 substrate specificity was similar to that of OsPAO5 preferring Spm and T-Spm but not Spd. Those enzymes also converted Spm and T-Spm to Spd, again indicative of PA back-conversion activities. Lastly, we show that OsPAO3, OsPAO4, and OsPAO5 are localized in peroxisomes. Together, these data revealed that constitutively and highly expressed O. sativa PAOs are localized in peroxisomes and catalyze PA back-conversion processes.

Tertiary tetraamines and quaternary pentaamines composed of aminopropyl and/or aminobutyl groups were synthesized as authentic samples for the identification of naturally occurring branched polyamines. Four tertiary tetraamines were obtained by alkylating the free secondary amine group of diphthaloyl derivatives of sym-norspermidine or sym-homospermidine with N-(3-bromopropyl)phthalimide or N-(4-bromobutyl)phthalimide in the presence of KF-Celite. Five quaternary pentaamines were obtained by fusing triphthaloyl derivatives of the tertiary tetraamines with an excess amount of N-(3-iodopropyl)phthalimide or N-(4-iodobutyl)phthalimide. The present methods are simple and achieved high yields. The 13C-NMR spectra of these branched polyamines were recorded in D2O as fully protonated forms, and all 13C chemical shifts were assigned consistently.

Polyamines of 18 leguminous mature seeds were analyzed by high-performance liquid chromatography and gas chromatography – mass spectrometry. Putrescine, spermidine, and spermine occurred ubiquitously and cadaverine, agmatine, and homospermidine were sporadically found in these seeds. Six unusual polyamines, i.e., canavalmine [NH2(CH2)4NH(CH2)3NH(CH2)4NH2], homospermine [NH2(CH2)4NH(CH2)4NH(CH2)4NH2], aminopropylcanavalmine [NH2(CH2)3NH(CH2)4NH(CH2)3NH(CH2)4NH2], thermospermine [NH2(CH2)3NH(CH2)3NH(CH2)4NH2], and aminopropylhomospermidine [NH2(CH2)3NH(CH2)4NH(CH2)4NH2] were found in the seeds of Pisum sativum. Thermospermine and aminopropylhomospermidine were also detected in the seeds of Vicia hirsuta and Trifolium pratense, respectively. An unusual tetraamine, norspermine [NH2(CH2)3NH(CH2)3NH(CH2)3NH2], was found in the seeds of Medicago sativa and Vicia faba. The seeds of Phaseolus coccineus contained homospermine and a tertiary branched pentaamine, N5-aminobutylhomospermine [NH2(CH2)4N((CH2)4NH2)(CH2)4NH(CH2)4NH2]. Key words: poly amine, legume, seed.

Polyamines of thermophilic Gram-negative eubacteria, "Rhodothermus marinus" ATCC 43812, Thermus sp. ATCC 43814 and Thermonema lapsum ATCC 43542 were analyzed by high-perfomance liquid chromatography and gas chromatography-mass spectrometry. "R. marinus" contained spermidine, spermine, thermopentamine, a tertiary tetraamine (N4-aminopropylspermidine) and a quaternary pentaamine (N4-bis(aminopropyl) spermidine). Thermus sp. ATCC 43814 contained putrescine, cadaverine, norspermidine, spermidine, homospermidine, norspermine, spermine, thermospermine, aminopropylhomospermidine, caldopentamine, agmatine, two tertiary tetraamines (N4-aminopropylnorspermidine and N4-aminopropylspermidine) and two quaternary pentaamines (N4-bis(aminopropyl)norspermidine and N4-bis(aminopropyl)spermidine). Homospermidine and homospermine were detected in Thermonema lapsum as the major polyamine. These distribution patterns of long and branched polyamines are distinctive in the thermophiles, indicating that unusual polyamine profiles serve to estimate chemotaxonomic and phylogenetic relationships within thermophilic eubacteria.