Polyamines of the hyperthermophilic archaebacteria belonging to the genera Thermococcus and Methanothermus and two new genera Caldivirga and Palaeococcus

Cellular polyamines of eight new thermophilic archaebacteria were investigated to determine the chemotaxonomic significance of polyamine distribution profiles. Hyperthermoacidophilic Caldivirga maquilingensis belonging to the family Thermoproteaceae of the Crenarchaeota have a unique polyamine profile comprising spermidine, norspermidine and norspermine as the major polyamines. Within the order Thermococcales of the Euryarchaeota, the major polyamines of an extremely thermophilic terrestrial species of Thermococcus, T. zilligii, were spermidine and agmatine, whereas hyperthermophilic submarine species of Thermococcus and hyperthermophilic submarine Palaeococcus ferrophilus contained a quaternary branched penta-amine, N4-bis(aminopropyl)spermidine, as a major polyamine. A hyperthermophilic methanogen, Methanothermus sociabilis, belonging to Euryarchaeota, contained spermidine and spermine as the major polyamine.     

Polyamine analysis for chemotaxonomy of thermophilic eubacteria: Polyamine distribution profiles within the orders Aquificales, Thermotogales, Thermodesulfobacteriales, Thermales, Thermoanaerobacteriales, Clostridiales and Bacillales

Cellular polyamines of 45 thermophilic and 8 related mesophilic eubacteria were investigated by HPLC and GC analyses for the thermophilic and chemotaxonomic significance of polyamine distribution profiles. Spermidine and a quaternary branched penta-amine, N4-bis(aminopropyl)norspermidine, were the major polyamine in Thermocrinis, Hydrogenobacter, Hydrogenobaculum, Aquifex, Persephonella, Sulfurihydrogenibium, Hydrogenothermus, Balnearium and Thermovibrio, located in the order Aquificales. Thermodesulfobacterium and Thermodesulfatator belonging to the order Thermodesulfobacteriales contained another quaternary penta-amine, N4-bis(aminopropyl)spermidine. In the order Thermotogales, Thermotoga contained spermidine, norspermidine, caldopentamine and homocaldopentamine. The latter two linear penta-amines were not found in Marinitoga and Petrotoga. In the order Thermales, Thermus and Marinithermus contained homospermidine, norspermine and the linear penta-amines. Meiothermus lacked penta-amines. Vulcanithermus contained linear penta-amines and hexa-amines but not homospermidine. Oceanithermus contained spermine alone. Within the order Thermoanaerobacteriales, the two quaternary branched penta-amines were found in Thermanaeromonas and Thermoanaerobacter. Caldanaerobacter contained N4-bis(aminopropyl)spermidine. Thermoanaerobacterium lacked penta-amines. Thermaerobacter of the order Clostridiales contained N4-bis(aminopropyl)spermidine and agmatine. Thermosyntropha, Thermanaerovibrio, Thermobrachium ( the order Clostridiales), Sulfobacillus, Alicyclobacillus, Anoxybacillus, Ureibacillus, Thermicanus ( the order Bacillales), Desulfotomaculum, Desulfitobacterium and Pelotomaculum (the family Peptococcaceae) ubiquitously contained spermine. Some thermophiles of Bacillales added linear and branched penta-amines.     

Cellular polyamines of the acidophilic, thermophilic and thermoacidophilic archaebacteria, Acidilobus, Ferroplasma, Pyrobaculum, Pyrococcus, Staphylothermus, Thermococcus, Thermodiscus and Vulcanisaeta

Cellular polyamines of newly isolated acidophilic, thermophilic and thermoacidophilic archaebacteria were investigated for the chemotaxonomic significance of polyamine distribution profiles. In addition to spermidine, spermine and agmatine, a quaternary branched penta-amine, N(4)-bis(aminopropyl)spermidine, was found in thermophilic Thermococcus waiotapuensis, Thermococcus aegaeus and Pyrococcus glycovorans belonging to the order Thermococcales. An acidophilic euryarchaeon, Ferroplasma acidiphilum located in the order Thermoplasmatales, contained spermidine and agmatine. Norspermidine, spermidine, norspermine and spermine were found in thermoacidophilic Acidilobus aceticus and thermophilic Thermodiscus maritimus located in the order Desulfurococcales, and in thermophilic Pyrobaculum arsenaticum, Pyrobaculum oguniense, Vulcanisaeta distributa and Vulcanisaeta souniana belonging to the order Thermoproteales; however, the four genera differ on their tetra- and penta-amine levels. Thermophilic Staphylothermus hellenicus belonging to Desulfurococcales contained caldopentamine, caldohexamine and N1-acetylcaldopentamine in addition to norspermidine, spermidine and norspermine. This is the first report on the occurrence of acetylated penta-amine in nature.     

Polyamine distributions in thermophilic eubacteria belonging to Thermus and Acidothermus

Triamines such as norspermidine, spermidine, and homospermidine and tetraamines such as norspermine, spermine, thermospermine, and aminopropylhomospermidine were found to be distributed ubiquitously in the eight extremely thermophilic (growing at 70 degrees C) Thermus species tested. Three linear pentaamine (caldopentamine, homocaldopentamine, and thermopentamine), two linear hexaamines (caldohexamine and homocaldohexamine), two tertiary branched tetraamines (N4-aminopropylnorspermidine and N4-aminopropyl-spermidine), and quaternary branched pentaamines such as N4-bis(aminopropyl)norspermidine and N4-bis(aminopropyl)spermidine were detected in T. thermophilus HB8, T. filiformis Wai33 A1, T. flavus AT-62, and T. caldophilus GK24. The linear hexaamines and branched polyamines were absent in T. aquaticus YT-1, T. sp. X-1, T. sp. T2, and T. sp. T351, in which linear pentaamines were minor components. Moderately thermophilic Thermus ruber and Thermus sp. K-2 contained putrescine, spermidine, norspermidine, homospermidine, spermine, norspermine, thermospermine, and aminopropylhomospermidine. No pentaamines, hexaamines, or branched polyamines were found in these two moderately thermophilic Thermus species. On the other hand, moderately thermophilic, acidophilic Acidothermus cellulolyticus was devoid of all the polyamines.     

Identification of a Novel Aminopropyltransferase Involved in the Synthesis of Branched-Chain Polyamines in Hyperthermophiles

Longer- and/or branched-chain polyamines are unique polycations found in thermophiles. N⁴-aminopropylspermine is considered a major polyamine in Thermococcus kodakarensis. To determine whether a quaternary branched penta-amine, N⁴-bis(aminopropyl)spermidine, an isomer of N⁴-aminopropylspermine, was also present, acid-extracted cytoplasmic polyamines were analyzed by high-pressure liquid chromatography, gas chromatography (HPLC), and gas chromatography-mass spectrometry. N⁴-bis(aminopropyl)spermidine was an abundant cytoplasmic polyamine in this species. To identify the enzyme that catalyzes N⁴-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 N⁴-bis(aminopropyl)spermidine synthesis activity was measured. Of the four candidates, TK1691 (BpsA) was found to synthesize N⁴-bis(aminopropyl)spermidine from spermidine via N⁴-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 N⁴-aminopropylspermidine and N⁴-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.     

Occurrence of uncommon polyamines in cultured tissues of maize

Summary The uncommon polyamines, norspermidine and norspermine, were detected in maizein vitro cultures of three different genotypes. The common polyamines, spermidine and spermine, along with the diamine, putrescine, were also observed. The total amounts of the uncommon polyamines, norspermidine and norspermine, were comparable to the total amounts of the common polyamines, spermidine and spermine, in the maize tissues. The titer for norspermidine was 6- to 15-fold greater than that of its common counterpart (spermidine) in the three genotypes. Norspermidine was the predominant polyamine among all triamines and tetramines detected in cell cultures of two of the three genotypes of maize examined and was predominant along with spermine in the third genotype. Enzyme assays performed with extracts from callus of one of the genotypes suggested a likely mechanism to account for the biosynthesis of the uncommon polyamines in cultured maize cells, through the actions of putrescine aminopropyltransferase, polyamine oxidase, and Schiff-base reductase/decarboxylase enzyme activities. This is the first report of the detection of uncommon polyamines in maize tissues, as well as the first report of these uncommon polyamines in a monocotyledonous plant.     

Oxidized polyamines and the growth of human vascular endothelial cells. Prevention of cytotoxic effects by selective acetylation.

The responses of human umbilical-vein vascular endothelial cells in culture to the naturally occurring polyamines spermine, spermidine and putrescine, their acetyl derivatives and oxidation products were examined. In the absence of human polyamine oxidase, exposure of cells to polyamines (up to 160 microM) had no adverse effects. In the presence of polyamine oxidase, spermine and spermidine were cytotoxic, but putrescine was not. Acetylation of the aminopropyl group of spermidine or both aminopropyl groups of spermine prevented this cytotoxicity. The amino acids corresponding to the polyamines, representing a further stage of oxidation, were also without effect. The cytotoxic effects were irreversible. Use of bovine serum amine oxidase in place of the human enzyme gave qualitatively similar results.     

Identification of a novel acetylated form of branched-chain polyamine from a hyperthermophilic archaeon Thermococcus kodakarensis

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.     

Effect of N1,N12-bis(ethyl)spermine and related compounds on growth and polyamine acetylation, content, and excretion in human colon tumor cells

Exposure of human colon tumor (HT 29 cells) to N1,N12-bis(ethyl)spermine and analogs produced a rapid loss of intracellular polyamines. This loss was brought about predominantly by an increased excretion of spermidine. N1,N11-Bis(ethyl)norspermine and N1,N12-Bis(ethyl)spermine were potent inducers of spermidine/spermine N1-acetyltransferase, and this induction facilitated the efflux of polyamines by enhancing the conversion of spermine into spermidine. N1,N14-Bis(ethyl)homospermine, which did not induce spermidine/spermine N1-acetyltransferase, also caused the loss of spermidine from the cell but was less effective in bringing about the decline in intracellular spermine. These results indicate that cellular polyamine levels can be regulated by excretion of spermidine and that the bis(ethyl)spermine derivatives deplete intracellular polyamine content by interference with this process.     

Regulation of spermidine/spermine N1-acetyltransferase in L6 cells by polyamines and related compounds.

Exposure of rat L6 cells in culture to exogenous polyamines led to a very large increase in the activity of spermidine/spermine N1-acetyltransferase. Spermine was more potent than spermidine in bringing about this increase, but in both cases the elevated acetyltransferase activity increased the cellular conversion of spermidine into putrescine. The N1-acetyltransferase turned over very rapidly in the L6 cells, with a half-life of 9 min after spermidine and 18 min after spermine. A wide variety of synthetic polyamine analogues also brought about a substantial induction of spermidine/spermine N1-acetyltransferase activity. These included sym-norspermidine, sym-norspermine, sym-homospermidine, N4-substituted spermidine derivatives, 1,3,6-triaminohexane, 1,4,7-triaminoheptane and deoxyspergualin, which were comparable with spermidine in their potency, and N1N8-bis(ethyl)spermidine, N1N9-bis(ethyl)homospermidine, methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone) and 1,1'-[(methylethanediylidene)dinitrilo]bis(3-amino-guanidine ), which were even more active than spermidine. It is suggested that these polyamine analogues may bring about a decrease in cellular polyamines not only by inhibiting biosynthesis but by stimulating the degradation of spermidine into putrescine.     

Further study on polyamine compositions in Vibrionaceae

It has previously been reported that norspermidine, one of the unusual polyamines, is present in Vibrio species. To expand this observation, the cellular polyamine compositions of additional species and strains in the family Vibrionaceae (Vibrio, Photobacterium, Listonella, and Shewanella) as well as Aeromonas species and Plesiomonas shigelloides, which have been proposed to be excluded from Vibrionacea, were determined by using gas-liquid chromatography. Some Vibrio species previously reported were reexamined under the same conditions, and their results are included in this report. Norspermidine was detected as a major triamine in 23 of 24 Vibrio species, all of 4 Listonella species, and 3 of 5 Photobacterium species. Vibrio costicola, Photobacterium fischeri, and Photobacterium phosphoreum contained no norspermidine. Listonella species were indistinguishable from Vibrio species in their polyamine profiles. However, Schewanella putrefaciens ATCC 8071, formerly allocated in the genus Alteromonas, contained no norspermidine, and its polyamine profile was similar to those of four Aeromonas species, in which putrescine was exclusively found. Plesiomonas shigelloides was very similar to Escherichia coli in that putrescine and spermidine were predominant polyamines. Our data indicate that the occurrence of norspermidine may be very helpful as a generic marker in identification and classification of Vibrio and Listonella species. A gas-liquid chromatographic method with a nitrogen-selective detector was presented for rapid and sensitive detection of cellular norspermidine.     

Crystal structures and enzymatic properties of a triamine/agmatine aminopropyltransferase from Thermus thermophilus

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.     

Metabolic stability of alpha-methylated polyamine derivatives and their use as substitutes for the natural polyamines

Metabolically stable polyamine derivatives may serve as useful surrogates for the natural polyamines in studies aimed to elucidate the functions of individual polyamines. Here we studied the metabolic stability of alpha-methylspermidine, alpha-methylspermine, and bis-alpha-methylspermine, which all have been reported to fulfill many of the putative physiological functions of the natural polyamines. In vivo studies were performed with the transgenic rats overexpressing spermidine/spermine N(1)-acetyltransferase. alpha-Methylspermidine effectively accumulated in the liver and did not appear to undergo any further metabolism. On the other hand, alpha-methylspermine was readily converted to alpha-methylspermidine and spermidine; similarly, bis-alpha-methylspermine was converted to alpha-methylspermidine to some extent, both conversions being inhibited by the polyamine oxidase inhibitor N(1), N(2)-bis(2,3-butadienyl)-1,4-butanediamine. Furthermore, we used recombinant polyamine oxidase, spermidine/spermine N(1)-acetyltransferase, and the recently discovered spermine oxidase in the kinetic studies. In vitro studies confirmed that methylation did not protect spermine analogs from degradation, whereas the spermidine analog was stable. Both alpha-methylspermidine and bis-alpha-methylspermine overcame the proliferative block of early liver regeneration in transgenic rats and reversed the cytostasis induced by an inhibition of ornithine decarboxylase in cultured fetal fibroblasts.     

Distinct difference in the polyamine compositions of bryophyta and pteridophyta

Polyamine contents of various species of plants and fungi including Bryophyta, Pteridophyta, Gymnospermae, Ascomycota, Basidiomycota, and Lichenobionta were determined by the combination of six chromatographic techniques. Polyamines examined included putrescine, spermidine, spermine, 1,3-diaminopropane (diaminopropane), sym-norspermidine (norspermidine), sym-norspermine (norspermine), thermospermine, caldopentamine, homocaldopentamine, cadaverine, aminopropylcadaverine, sym-homospermidine (homospermidine), agmatine, and canavalmine. In addition to the widely occurring polyamines (putrescine, spermidine, and spermine), the "unusual" polyamines norspermidine and norspermine were found to be widely distributed in Bryophyta and Lichenobionta. These two polyamines were not detected in any species of Pteridophyta, Gymnospermae, and fungi even though their possible precursor, diaminopropane, was found in some species. Homospermidine was one of the major polyamines in Bryophyta and Lichenobionta, and was detected in most species of Pteridophyta and sporadically in higher plants. Agmatine was detected in most species of Bryophyta and in certain species of Gymnospermae. These data suggest that norspermidine, norspermine, and homospermidine can serve as chemical phylogenic and taxonomic markers in Plantae and Fungi.     

Polyamines of primitive apterygotan insects: springtails, silverfish and a bristletail

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 micromol/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 micromol/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.     

Polyamine‐independent growth and biofilm formation,and functional spermidine/spermine N‐acetyltransferases in Staphylococcus aureus and Enterococcus faecalis

Polyamines such as spermidine and spermine are primordial polycations that are ubiquitously present in the three domains of life. We have found that Gram‐positive bacteria Staphylococcus aureus and Enterococcus faecalis have lost either all or most polyamine biosynthetic genes, respectively, and are devoid of any polyamine when grown in polyamine‐free media. In contrast to bacteria such as Pseudomonas aeruginosa, Campylobacter jejuni and Agrobacterium tumefaciens, which absolutely require polyamines for growth, S. aureus and E. faecalis grow normally over multiple subcultures in the absence of polyamines. Furthermore, S. aureus and E. faecalis form biofilms normally without polyamines, and exogenous polyamines do not stimulate growth or biofilm formation. High levels of external polyamines, including norspermidine, eventually inhibit biofilm formation through inhibition of planktonic growth. We show that spermidine/spermine N‐acetyltransferase (SSAT) homologues encoded by S. aureus USA300 and E. faecalis acetylate spermidine, spermine and norspermidine, that spermine is the more preferred substrate, and that E. faecalis SSAT is almost as efficient as human SSAT with spermine as substrate. The polyamine auxotrophy, polyamine‐independent growth and biofilm formation, and presence of functional polyamine N‐acetyltransferases in S. aureus and E. faecalis represent a new paradigm for bacterial polyamine biology.     

Polyamine metabolism in Acanthamoeba: polyamine content and synthesis of ornithine, putrescine, and diaminopropane

Five polyamines which could be separated by high performance liquid chromatography were found in Acanthamoeba castellanii (strain Neff). These included in order of decreasing abundance: 1,3-diaminopropane, spermidine, spermine, norspermidine, and putrescine. Only diaminopropane and norspermidine had been found previously. Spermine was present in cultures grown in broth, but not in defined medium. Radioactive substrates were used to establish that putrescine was synthesized by decarboxylation of ornithine, ornithine was synthesized from arginine or citrulline, and diaminopropane was synthesized from spermidine. The presence of ornithine decarboxylase (EC 4.1.1.17), arginase (EC 3.5.3.1), and urease (EC 3.5.1.5) and the absence of arginine decarboxylase (EC 4.1.1.19) were established. A scheme for polyamine biosynthesis in A. castellanii is proposed.     

Polyamine Metabolism in Acanthamoeba: Polyamine Content and Synthesis of Ornithine,Putrescine, and Diaminopropane1

Five polyamines which could be separated by high performance liquid chromatography were found in Acanthamoeba castellanii (strain Neff). These included in order of decreasing abundance: 1,3-diaminopropane, spermidine, spermine, norspermidine, and putrescine. Only diaminopropane and norspermidine had been found previously. Spermine was present in cultures grown in broth, but not in defined medium. Radioactive substrates were used to establish that putrescine was synthesized by decarboxylation of ornithine, ornithine was synthesized from arginine or citrulline, and diaminopropane was synthesized from spermidine. The presence of ornithine decarboxylase (EC 4.1.1.17), arginase (EC 3.5.3.1), and urease (EC 3.5.1.5) and the absence of arginine decarboxylase (EC 4.1.1.19) were established. A scheme for polyamine biosynthesis in A. castellanii is proposed.     

Cloning and characterization of spermidine synthase and its implication in polyamine biosynthesis in Helicobacter pylori strain 26695

The HP0832 (speE) gene of Helicobacter pylori strain 26695 codes for a putative spermidine synthase, which belongs to the polyamine biosynthetic pathway. Spermidine synthase catalyzes the production of spermidine from putrescine and decarboxylated S-adenosylmethionine (dcSAM), which serves as an aminopropyl donor. The deduced amino acid sequence of the HP0832 gene shares less than 20% sequence identity with most spermidine synthases from mammalian cells, plants and other bacteria. In this study, the HP0832 open reading frame (786 bp) was cloned into the pQE30 vector and overexpressed in Escherichia coli strain SG13009. The resulting N-terminally 6xHis-tagged HP0832 protein (31.9 kDa) was purified by Ni-NTA affinity chromatography at a yield of 15 mg/L of bacteria culture. Spermidine synthase activity of the recombinant protein was confirmed by the appearance of spermidine after incubating the enzyme with putrescine and dcSAM. Substrate specificity studies have shown that spermidine could not replace putrescine as the aminopropyl acceptor. Endogenous spermidine synthase of H. pylori was detected with an antiserum raised against the recombinant HP0832 protein. H. pylori strain 26695 contains putrescine and spermidine at a molar ratio of 1:3, but no detectable spermine or norspermidine was observed, suggesting that the spermidine biosynthetic pathway may provide the main polyamines in H. pylori strain 26695.     

Synthesis of novel polyamines in Paracoccus, Rhodobacter and Micrococcus

Abstract The Gram-negative facultative chemolithotroph, Paracoccus denitrificans contains putrescine, cadaverine, agmatine, spermidine, aminopropylcadaverine, spermine, thermospermine and aminopentylnorspermidine. This bacterium has the ability to produce norspermidine from supplemented diaminopropane. The halophile, Paracoccus halodenitrificans is devoid of any polyamines. Neither decarboxylation of ornithine, lysine or arginine, nor triamine synthetic activity from diamines was detected in this halophile. Two Gram-negative facultative photoautotrophs, Rhodobacter sphaeroides and Rhodobacter capsulatus contain putrescine, cadaverine, agmatine and spermidine and can produce norspermidine from supplemented diaminopropane. A Gram-negative eubacterium, Micrococcus cryophilus , contains histamine and homospermidine in addition to putrescine, cadaverine and spermidine. Hence, polyamine distribution patterns and polyamine biosynthetic activities were very different among the four groups of Gram-negative eubacteria examined.