Inhibition of Shigella flexneri-induced transepithelial migration of polymorphonuclear leucocytes by cadaverine

Dysentery caused by Shigella species is characterized by infiltration of polymorphonuclear leucocytes (PMNs) into the colonic mucosa. Shigella spp. evolved into pathogens by the acquisition of virulence genes and by the deletion of 'antivirulence' genes detrimental to its pathogenic lifestyle. An example is cadA (encoding lysine decarboxylase), which is uniformly absent in Shigella spp., whereas it is present in nearly all isolates of the closely related non-pathogen Escherichia coli. Here, using monolayers of T84 cells to model the human intestinal epithelium, we determined that the introduction of cadA into S. flexneri and the expression of lysine decarboxylase attenuated the bacteria's ability to induce PMN influx across model intestinal epithelium. Such inhibition was caused by cadaverine generated from the decarboxylation of lysine. Cadaverine treatment of model intestinal epithelia specifically inhibited S. flexneri induction of PMN transepithelial migration, while having no effect on the ability of Salmonella or enteropathogenic E. coli (EPEC) to induce PMN migration. These observations not only provide insight into mechanisms of S. flexneri pathogen evolution and pathogenesis, but also suggest a potential for the use of cadaverine in the treatment of dysentery.

Biogenic amine survey and organoleptic changes in fresh, stored, and temperature-abused bluefish (Pomatomus saltatrix)

Changes in histamine, putrescine, and cadaverine concentrations in bluefish filets (Pomatomus saltatrix) stored at 5, 10, and 15 degrees C were determined using high-performance liquid chromatography. An organoleptic assessment was conducted simultaneously with the biogenic amine analyses. The histamine levels found in fresh bluefish obtained from wholesale seafood distributors ranged between <1 ppm and 99 with an average of 39 ppm. Putrescine and cadaverine were not found in fresh bluefish. Fish fillets stored at each of the three temperatures developed histamine. The greatest accumulation of histamine was observed in fish stored at 15 degrees C, which developed histamine levels as high as 2,200 ppm. Putrescine levels increased at each temperature during storage. Cadaverine was present only in uninoculated bluefish stored at 15 degrees C. Histamine achieved higher levels in bluefish pieces inoculated with Morganella morganii, which demonstrates that bluefish support bacterial histamine formation. Histamine levels at each temperature exceeded the 50-ppm advisory level established by the Food and Drug Administration before 100% sensory rejection. Standard plate counts increased during storage of fish at all temperatures, but the correlation between histamine levels and standard plate count was not significant.

Is the lack of concurrence of bacterial vaginosis and vaginal candidosis explained by the presence of bacterial amines?

OBJECTIVE AND STUDY DESIGN

We report for the first time an inhibitory effect on cell division and germ tube formation by Candida albicans and strains of other Candida species by putrescine and cadaverine.

RESULTS

Both bacterial amines showed a dose-dependent inhibition of germ tube formation by C albicans, as well as budding (inhibition of cell division) of strains of other Candida species (ie, C glabrata, C krusei, and C tropicalis).

CONCLUSIONS

We hypothesize that the presence of these and possibly other bacterial amines produced by anaerobes in the vaginal flora and seen in bacterial vaginosis, as in the healthy gut, may explain why candidosis is rarely seen in these instances.

Cloning and kinetic characterization of the Trypanosoma cruzi S-adenosylmethionine decarboxylase

The gene for S-adenosylmethionine decarboxylase (AdoMetDC), a rate-limiting enzyme in the biosynthesis of polyamines, has been cloned from a Trypanosoma cruz cDNA library. The cDNA clone contains a 1.1 kb open reading frame predicted to encode a 42 kDa protein that shares 31% sequence identity to the human proenzyme. T. cruzi AdoMetDC expressed and purified from E. coli is auto-catalytically processed into two subunits of 32 kDa (alpha) and 10 kDa (beta). The catalytic activity of the purified recombinant enzyme is activated by the addition of putrescine to the reaction. To determine the effect of putrescine on the kinetics of the reaction, the velocity data collected at various substrate and putrescine concentrations were fit to the rate equation describing a non-essential activator. In the presence of fully saturating putrescine, k(cat) increases by 9-fold over the unactivated rate to 0.06 s(-1). The model derived Km for AdoMet is 0.05 mM in the absence of putrescine and the model-derived Kd for putrescine binding to free enzyme is 2.5 mM. The Km for AdoMet increases by alpha 2-fold when the enzyme is fully saturated with putrescine. Unlike human AdoMetDC, cadaverine activates the T. cruzi enzyme to a similar extent as putrescine.

Inhibition of receptor internalization by monodansylcadaverine selectively blocks p55 tumor necrosis factor receptor death domain signaling

The 55-kDa receptor for tumor necrosis factor (TR55) triggers multiple signaling cascades initiated by adapter proteins like TRADD and FAN. By use of the primary amine monodansylcadaverine (MDC), we addressed the functional role of tumor necrosis factor (TNF) receptor internalization for intracellular signal distribution. We show that MDC does not prevent the interaction of the p55 TNF receptor (TR55) with FAN and TRADD. Furthermore, the activation of plasmamembrane-associated neutral sphingomyelinase activation as well as the stimulation of proline-directed protein kinases were not affected in MDC-treated cells. In contrast, activation of signaling enzymes that are linked to the "death domain" of TR55, like acid sphingomyelinase and c-Jun-N-terminal protein kinase as well as TNF signaling of apoptosis in U937 and L929 cells, are blocked in the presence of MDC. The results of our study suggest a role of TR55 internalization for the activation of select TR55 death domain signaling pathways including those leading to apoptosis.

Purification and characterization of amine oxidase from pea seedlings

A novel, simple, and rapid procedure for the purification of pea seedling amine oxidase is reported. The crude enzyme, obtained by ammonium sulfate fractionation, was purified in two steps: the first one by anion-exchange chromatography and the second one by affinity chromatography. The first chromatography step was carried out on a diethylaminoethyl-cellulose column. By lowering the amount of protein loaded on the column and the buffer concentration it was possible to obtain an enzyme pure at 95% (sp act 1.2 microkat/mg). To achieve a higher degree of purification various affinity resins were prepared and tested. The resins were obtained by covalent immobilization of polyamines on Sepharose according to three different procedures. The best results were obtained with 6-aminohexyl-Sepharose 2B, prepared using CNBr as coupling agent, and eluting the enzyme by a solution containing 1, 4-diaminocyclohexane. This last compound was found to be a relatively strong competitive inhibitor of the oxidative deamination of cadaverine catalyzed by pea seedling amine oxidase (Ki = 32 microM). According to this procedure an electrophoretically homogeneous enzyme, characterized by a specific activity of 1.63 microkat/mg, was obtained.

Distinct sensitivities of OmpF and PhoE porins to charged modulators

The inhibition of the anion-selective PhoE porin by ATP and of the cation-selective OmpF porin by polyamines has been previously documented. In the present study, we have extended the comparison of the inhibitor-porin pairs by investigating the effect of anions (ATP and aspartate) and positively charged polyamines (spermine and cadaverine) on both OmpF and PhoE with the patch-clamp technique, and by comparing directly the gating kinetics of the channels modulated by their respective substrates. The novel findings reported here are (1) that the activity of PhoE is completely unaffected by polyamines, and (2) that the kinetic changes induced by ATP on PhoE or polyamines on OmpF suggest different mechanisms of inhibition. ATP induces a high degree of flickering in the PhoE-mediated current and appears to behave as a blocker of ion flow during its presumed transport through PhoE. Polyamines modulate the kinetics of openings and closings of OmpF, in addition to promoting a blocker-like flickering activity. The strong correlation between sensitivity to inhibitors and ion selectivity suggests that some common molecular determinants are involved in these two properties and is in agreement with the hypothesis that polyamines bind inside the pore of cationic porins.

Excretion of endogenous cadaverine leads to a decrease in porin-mediated outer membrane permeability

The permeability of the outer membrane of Escherichia coli to hydrophilic compounds is controlled by porin channels. Electrophysiological experiments showed that polyamines inhibit ionic flux through cationic porins when applied to either side of the membrane. Externally added polyamines, such as cadaverine, decrease porin-mediated fluxes of beta-lactam antibiotics in live cells. Here we tested the effects of endogenously expressed cadaverine on the rate of permeation of cephaloridine through porins, by manipulating in a pH-independent way the expression of the cadBA operon, which encodes proteins involved in the decarboxylation of lysine to cadaverine and in cadaverine excretion. We report that increased levels of excreted cadaverine correlate with a decreased outer membrane permeability to cephaloridine, without any change in porin expression. Cadaverine appears to promote a sustained inhibition of porins, since the effect remains even after removal of the exogenously added or excreted polyamine. The cadaverine-induced inhibition is sufficient to provide cells with some resistance to ampicillin but not to hydrophobic antibiotics. Finally, the mere expression of cadC, in the absence of cadaverine production, leads to a reduction in the amounts of OmpF and OmpC proteins, which suggests a novel mechanism for the environmental control of porin expression. The results presented here support the notion that polyamines can act as endogenous modulators of outer membrane permeability, possibly as part of an adaptive response to acidic conditions.

Characterization of 101-kDa transglutaminase from Physarum polycephalum and identification of LAV1-2 as substrate

Plasmodial transglutaminase of Physarum polycephalum was purified by anion exchange and hydrophobic chromatography. Gel filtration and SDS-polyacrylamide gel electrophoresis indicate that it is a monomer of 96-101 kDa. It is Ca2+-dependent, with half-maximal activity at 0. 7 mM Ca2+. Optimal activity occurs at pH 7.5 and at 50 mM KCl. Inactivation by N-ethylmaleimide indicates that it is a thiol enzyme. With N,N-dimethylcasein as substrate, the Km for monodansylcadaverine is 33.9 +/- 1.8 microM. Damage of plasmodia by brief treatment with 15% ethanol activates the transglutaminase, with rapid accumulation of cross-linked proteins unable to enter gels during SDS-polyacrylamide gel electrophoresis. Added monodansylcadaverine is conjugated principally to LAV1-2, a plasmodia-specific 40-kDa protein with four EF-hand sequences believed to bind Ca2+. Actin is seen as an additional substrate only in plasmodial homogenates. Immunoblots show that upon ethanol treatment, a portion of LAV1-2 is modified quickly and shifts to 36 kDa; another portion is cross-linked to itself or other proteins. The modification of LAV1-2 may lead to localized release of Ca2+ and activation of transglutaminase for walling off damaged areas of plasmodia. No significant increase in amount of the transglutaminase occurs during starvation-induced differentiation of plasmodia to form spherules, but a 50% reduction in the amount of total protein leads to a doubling in the specific mass of the TGase. Neither the transglutaminase nor LAV1-2 is found in the ameboid form of the organism.

Assembly in vitro of vitelline envelope components induced by a cortical alveolus sialoglycoprotein of eggs of the fish Tribolodon hakonensis

Assembly in vitro of vitelline envelope (VE) components, which were precipitated by 50-70% saturated ammonium sulphate from VE extracts, was induced by the action of a sialoglycoprotein that is immunohistochemically localised in cortical alveoli of fish eggs and has serine proteinase activity. The VE components consisted of major bands of molecular mass about 150-120, 110-100, 70 and 27 kDa in addition to about 20 minor bands and contained a chorionic transglutaminase, visualised as two fluorescent bands by monodansylcadaverine staining. The VE component assembly in vitro was Ca(2+)-dependent, not induced if the sialoglycoprotein was pretreated with a serine proteinase inhibitor, and inhibited by the presence of p-chloromercuribenzoate, iodoacetamide or L-cysteine in the reaction medium system. Electron microscopy revealed that assembly in vitro of the VE components consisted of aggregates of network sheets, consisting of branching and anastomosing thin (approximately 27-52 nm) and thick (approximately 137-376 nm) filamentous substances. Separation by SDS-PAGE showed that a considerable number of VE components participated in the assembly in vitro in various amounts. These results suggest at least partial reproduction of the phenomena that occur in the process of fertilisation envelope (FE) formation, and provide a new approach to investigation of the process of FE assembly in vitro.

Detection and characterization, using fluoresceincadaverine, of amine acceptor protein substrates accessible to active transglutaminase expressed by rabbit articular chondrocytes

The purpose of this study was to investigate the implication of transglutaminases in the biology of articular chondrocytes. Transglutaminase activity measurements performed on cell lysates showed that a transglutaminase was present in chondrocytes in primary culture and that it was strongly activated by limited proteolysis. In chondrocytes dedifferentiated by subculture or retinoic acid treatment, this transglutaminase appeared to be downregulated, while type II transglutaminase expression was induced. However, protein levels, mRNA steady-state levels or transglutaminase activity in whole-cell lysates do not necessarily reflect the activity present in living cells, as it is strongly regulated. Therefore, Fluoresceincadaverine, a fluorescent polyamine, was used for detecting amine acceptor protein substrates accessible to active transglutaminase in living cells. After incubation of chondrocytes with Fluoresceincadaverine, dedifferentiated cells exhibited an extracellular labelling, while chondrocytes in primary culture did not, unless thrombin was added to the culture medium. In contrast, Fluoresceincadaverine labelling was not detected in the cytosol, although the transglutaminases were also partly cytosolic. By confocal microscopy and Western blot analysis of labelled cells in culture, fibronectin was shown to be the main substrate for both transglutaminases. The transglutaminases present in articular chondrocytes may, therefore, contribute to the organization and the stabilization of their extracellular matrix.

Coagulation factor XIIIa undergoes a conformational change evoked by glutamine substrate. Studies on kinetics of inhibition and binding of XIIIA by a cross-reacting antifibrinogen antibody

Coagulation factor XIIIa, plasma transglutaminase (endo-gamma-glutamine:epsilon-lysine transferase EC 2.3.2.13) catalyzes isopeptide bond formation between glutamine and lysine residues and rapidly cross-links fibrin clots. A monoclonal antibody (5A2) directed to a fibrinogen Aalpha-chain segment 529-539 was previously observed from analysis of end-stage plasma clots to block fibrin alpha-chain cross-linking. This prompted the study of its effect on nonfibrinogen substrates, with the prospect that 5A2 was inhibiting XIIIa directly. It inhibited XIIIa-catalyzed incorporation of the amine donor substrate dansylcadaverine into the glutamine acceptor dimethylcasein in an uncompetitive manner with respect to dimethylcasein utilization and competitively with respect to dansylcadaverine. Uncompetitive inhibition was also observed with the synthetic glutamine substrate, LGPGQSKVIG. Theoretically, uncompetitive inhibition arises from preferential interaction of the inhibitor with the enzyme-substrate complex but is also found to inhibit gamma-chain cross-linking. The conjunction of the uncompetitive and competitive modes of inhibition indicates in theory that this bireactant system involves an ordered reaction in which docking of the glutamine substrate precedes the amine exchange. The presence of substrate enhanced binding of 5A2 to XIIIa, an interaction deemed to occur through a C-terminal segment of the XIIIa A-chain (643-658, GSDMTVTVQFTNPLKE), 55% of which comprises sequences occurring in the fibrinogen epitope Aalpha-(529-540) (GSESGIFTNTKE). Removal of the C-terminal domain from XIIIa abolishes the inhibitory effect of 5A2 on activity. Crystallographic studies on recombinant XIIIa place the segment 643-658 in the region of the groove through which glutamine substrates access the active site and have predicted that for catalysis, a conformational change may accompany glutamine-substrate binding. The uncompetitive inhibition and the substrate-dependent binding of 5A2 provide evidence for the conformational change.

The intermediate filament protein, vimentin, in the lens is a target for cross-linking by transglutaminase

Mere addition of Ca2+ to a lens cortical homogenate (bovine) generates a series of products composed of a variety of high molecular weight vimentin species. The Ca2+-induced cross-linking of this cytoskeletal element seems to be mediated by the intrinsic transglutaminase of lens, because the reaction could be blocked at the monomeric state of vimentin by the inclusion of small synthetic substrates of the enzyme dansylcadaverine or dansyl-epsilon-aminocaproyl-Gln-Gln-Ile-Val. These compounds are known to compete against the Gln or Lys functionalities of proteins that would participate in forming the Nepsilon(gamma-glutamyl)lysine protein-to-protein cross-links. The cytosolic transglutaminase-catalyzed reactions could be reproduced with purified bovine lens vimentin and also with recombinant human vimentin preparations. Employing the latter system, we have titrated the transglutaminase-reactive sites of vimentin and, by sequencing the dansyl-tracer-labeled segments of the protein, we have shown that residues Gln453 and Gln460 served as acceptor functionalities and Lys97, Lys104, Lys294, and Lys439 as electron donor functionalities in vimentin. The transglutaminase-dependent reaction of this intermediate filament protein might influence the shape and plasticity of the fiber cells, and the enzyme-catalyzed cross-linking of vimentin, in conjunction with other lens constituents, may contribute to the process of cataract formation.

Semenogelin I and semenogelin II, the major gel-forming proteins in human semen, are substrates for transglutaminase

The major seminal vesicle secreted proteins in human semen, semenogelin I and semenogelin II, interact non-covalently and via disulphide bridges to instantly form a coagulum upon ejaculation. The coagulum is liquefied after a few minutes due to the action of a prostatic serine protease, prostate-specific antigen (PSA). In contrast to rat semen, which forms an insoluble plug within minutes of expulsion, no transglutaminase-mediated cross-linking has been demonstrated in ejaculated human semen. However, we here show that semenogelin I and semenogelin II, both in seminal vesicle fluid and purified from semen, are substrates for factor XIIIa, the fibrin cross-linking transglutaminase. The cross-linking of the semenogelins, which was conformation-dependent, and the incorporation of a fluorescence-labelled amine, were visualised by SDS/PAGE and Western blot. Purified semenogelin I and semenogelin II could be cross-linked separately into complexes. Moreover, digestion of semenogelin with PSA produced fragments, some of which were cross-linked into complexes by factor XIIIa. We also found that PSA was unable to release any semenogelin fragments during exposure of the high molecular-mass complexes of cross-linked semenogelin to active PSA.

Purification and partial characterization of 76 kDa transglutaminase in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss

Transglutaminase (TGase), responsible for crosslinking between proteins, is known to be localized exclusively in the egg envelope (chorion) of rainbow trout, Oncorhynchus mykiss, and probably participates in the post-fertilization chorion hardening. We purified the TGase from unfertilized egg chorions by sequential chromatography using SP-Sepharose, Q-Sepharose, and TSK-gel G3000SWXL columns. The purified enzyme was a monomeric protein having the molecular mass of 76 kDa. It promoted incorporation of monodansyl-cadaverine into chorion protein and catalyzed the polymerization of chorion subunit proteins. The effect of various reagents suggested that the chorion TGase is a Ca2+-dependent SH-enzyme similar to the well-characterized TGases of various animals. The highest activity was observed at pH 6.0. The amines examined in the present study inhibited the TGase activity of the purified enzyme. However, they did not necessarily cause effective inhibition of its activity. These properties of the chorion TGase were essentially consistent with our previous observations on polymerization of chorion proteins, resulting in chorion hardening. We compared the amino acid composition of the purified TGase with those of the previously characterized TGases of fishes, such as chum salmon and red sea bream. The results suggest that the chorion 76 kDa TGase is not homologous with those liver TGases in terms of amino acid composition.

Reduced expression of tissue transglutaminase in a human endothelial cell line leads to changes in cell spreading, cell adhesion and reduced polymerisation of fibronectin

Tissue transglutaminase (tTgase, type II) is a Ca2+-dependent GTP binding protein which crosslinks proteins via (epsilon)((gamma)-glutamyl)lysine bridges. Although essentially a cytosolic enzyme there is increasing evidence to suggest the enzyme is externalised where it may play a role in extracellular matrix organisation. To investigate the function of this enzyme in a human umbilical endothelial cell line ECV304 tTgase expression was reduced in these cells by up to 90% by stable transfection with a 1.1. kb antisense construct in the plasmid vector pSG5. Two clones showing a reduction in expression of tTgase activity of 70 and 90% have been isolated and characterised. These clones show a number of phenotypic differences when compared to the parent cell line and the transfected controls which include reduced cell spreading and a decreased adhesion of cells on different substrata as measured by their susceptibility to removal by trypsin. Reduced cell spreading in the antisense transfected clones was accompanied by a decrease in the crosslinking of fibronectin into polymeric multimers which could be correlated to the amount of tTgase externalised by cells. A novel assay was developed to measure externalised tTgase activity which is cell mediated, inhibited by preincubation of cells with anti-tTgase antibody and relies on the incorporation of biotinylated cadaverine into fibronectin. The results of these experiments suggest that externalised tTgase may play a key role in a number of cell behavioural patterns which might be related to the enzymes ability to bind and crosslink fibronectin.

Polyamine metabolism in the thermotolerant mesophilic fungus Aspergillus fumigatus

Biomass production by Aspergillus fumigatus was greatest at 40-45 degrees C and was associated with an increase in concentration of the diamine putrescine and activity of its biosynthetic enzyme ornithine decarboxylase. Concentrations of the other amines, cadaverine, spermidine and spermine were considerably lower than putrescine concentration and did not change significantly over the temperature range 20-50 degrees C. This is surprising in view of the greatly increased flux of label from ornithine through to spermidine at 45 and 50 degrees C, indicating an increased formation of this triamine. It is suggested that there was increased formation of spermidine derivatives at these temperatures. Interestingly, there was greatly increased formation of the higher homologues of cadaverine, aminopropylcadaverine and N,N'-bis(3-aminopropyl)cadaverine, in A. fumigatus at 45 and 50 degrees C.

The use of Fluoresceincadaverine for detecting amine acceptor protein substrates accessible to active transglutaminase in living cells

The use of Fluoresceincadaverine as a primary amine donor for detecting the endogenous substrates for active transglutaminase in living cells was studied. Fluoresceincadaverine was found to be suitable for labelling cells in culture as it did not induce cytotoxicity when used at 0.5 mM in culture media and diffused throughout the cell. After appropriate fixation using methanol, Fluoresceincadaverine-labelled cells were observed by direct fluorescence microscopy, allowing visualization of the substrates for active transglutaminase. Simultaneous detection of transglutaminase and of Fluoresceincadaverine incorporated into proteins strongly suggested that cytosolic transglutaminase was inactive in these living cells. However, transglutaminase co-distributed with Fluoresceincadaverine-labelled structures, which resembled a lattice. Fluoresceincadaverine-labelled proteins detected by Western blotting using an anti-Fluorescein antibody showed that, in living cells, the major transglutaminase substrate migrated at an apparent molecular weight of 220 kDa, as does fibronectin. Fibronectin was found to co-distribute with Fluoresceincadaverine-labelled lattice. This confirmed that these lattice structures were extracellular and, therefore, that transglutaminase is in an active form in this compartment. This opportunity to perform morphological and biochemical analyses in the search for transglutaminase substrates in living cells should help in determining the specific function of transglutaminases in a particular cell type as well as in universal cellular events, such as apoptosis or cell growth.

Breath odor: etiopathogenesis, assessment and management

Oral malodor is a significant social disability which usually has a local cause, particularly arising from the oral flora. Malodor may arise from the lingual or periodontal flora, gram-negative anaerobes being the main organisms capable of releasing sulphur compounds from the putrefaction of debris and other material. Volatile sulphur compounds, cadaverine and other substances appear responsible for much of the malodor. Systemic disease may underlie some cases of oral malodor. The objective assessment of malodor is still best performed by the human sense of smell (organoleptic method) but more quantifiable measures are being developed.

Cross-linking of the NH2-terminal region of fibronectin to molecules of large apparent molecular mass. Characterization of fibronectin assembly sites induced by the treatment of fibroblasts with lysophosphatidic acid

Cell surface molecules on adherent cells that bind 125I-labeled fibronectin or its 70-kDa N-terminal fragment were identified by cross-linking with factor XIIIa and by photoaffinity labeling. Such cross-linking caused the 70-kDa fragment to become associated irreversibly to cell layers and was greater in cells treated with lysophosphatidic acid, an enhancer of fibronectin assembly and strong modulator of cell shape. Cross-linking of the 70-kDa fragment with factor XIIIa was to molecules that migrated in discontinuous sodium dodecyl sulfate-polyacrylamide gels at the top of the 3.3% stacking gel and near the top of the separating gel. Estimated sizes of these large apparent molecular mass molecules (LAMMs) were >>3 MDa and approximately 3 MDa. The label in 70-kDa fragment conjugated with 125I-sulfosuccinimidyl 2-(p-azidosalicylamido)-1, 3'-dithiopropionate was associated with >>3-MDa LAMMs without reduction and with approximately 3-MDa LAMMs after reduction and transfer of the cleavable label. The LAMMs were expressed on monolayer cells shortly after adherence, required both 1% Triton X-100 and 2 M urea for efficient extraction, and were susceptible to digestion with trypsin but not to cathepsin D digestion. Complexes of 125I-70-kDa fragment and LAMMs were also susceptible to limited acid digestion and Glu-C protease digestion but were not cleaved by chondroitin lyase or heparitinase. Neither the uncleaved complexes nor the cleavage products were immunoprecipitated with anti-fibronectin antibodies directed toward epitopes outside the 70-kDa region. Thus, cell surface molecules that are either very large or not dissociated in sodium dodecyl sulfate comprise the labile matrix assembly sites for fibronectin.

Formation of cadaverine derivatives in Saccharomyces cerevisiae

The higher homologues of cadaverine, aminopropylcadaverine (APC) and N,N-bis(3-aminopropyl)cadaverine (3APC) were formed by a wild-type strain of Saccharomyces cerevisiae, and by two mutant strains, spe 3-1 and spe 4-1, exhibiting point mutations in the genes for spermidine synthase and spermine synthase, respectively. This, together with the incomplete inhibition of APC and 3APC formation in the presence of inhibitors of S-adenosylmethionine decarboxylase and spermidine synthase, suggests that the cadaverine derivatives are formed partly by the operation of a different route. However, the yeast strains were unable to utilise [14C]aspartate and lysine to form APC and 3APC. Since the ornithine decarboxylase inhibitor alpha-difluoromethylornithine (DFMO) greatly reduced the formation of APC and 3APC, it is suggested that these compounds are formed preferentially in these yeast strains from cadaverine formed by ODC. APC and 3APC formation in the yeast strains was increased substantially following exposure to 37 degrees C for 2 h.

Site-specific modification of interleukin-2 by the combined use of genetic engineering techniques and transglutaminase

Exploring a new method for the site-specific incorporation of functional groups into proteins, we have studied the combined use of genetic engineering techniques and enzymatic methods. Specifically, a short peptide for use as a substrate of guinea pig liver transglutaminase (TGase) is introduced at the N terminus of human interleukin-2 (hIL-2). The expressed chimeric protein (rTG1-IL-2) is chemically modified at a glutamine site in the appended sequence by TGase-catalyzed transamination with two amines, monodansylcadaverine (MDC), or a constructed derivative of poly (oxyethylene) (POE3). For the TGase-catalyzed modifications with MDC and POE3, 1 mol of donor was incorporated per mole of rTG1-IL-2, respectively. N-Terminal sequence analysis of MDC-modified rTG1-IL-2 (MDC-rTG1-IL-2) showed that the Gln-4 residue in the chimeric protein was site specifically modified with MDC. On the other hand, tryptic mapping of POE3-modified rTG1-IL-2 (POE3-rTG1-IL-2) by matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOFMS) suggested that one of the Gln sites in the appended sequence was modified with POE3. The POE3-rTG1-IL-2 retained full bioactivity relative to the unmodified molecule and rhIL-2. This methodology could be a new and general route for the site-specific modification of proteins.

Core histones are glutaminyl substrates for tissue transglutaminase

Chicken erythrocyte core histones are glutaminyl substrates in the transglutaminase (TGase) reaction with monodansylcadaverine (DNC) as donor amine. The modification is very fast when compared with that of many native substrates of TGase. Out of the 18 glutamines of the four histones, nine (namely glutamine 95 of H2B; glutamines 5, 19, and 125 of H3; glutamines 27 and 93 of H4; and glutamines 24, 104, and 112 of H2A) are the amine acceptors in free histones. The use of Gln112 of H2A requires a temperature-dependent partial unfolding of the histone, showing that structural determinants are decisive for the glutamine specificity. The structures of H2A and H2B do not appreciably change upon modification with DNC as determined by circular dichroism, and core particles reconstituted from these DNC-modified histones are indistinguishable from native nucleosome cores. When the reaction is carried out with native nucleosomes, only glutamines 5 and 19 of H3, which are located in the N-terminal tail, and glutamine 22 of H2B, which is not labeled in free histone, are modified. Methylamine and putrescine also are incorporated into nucleosomes by the TGase reaction. Our results reveal several possibilities for the application of the TGase reaction in the chromatin field, and taking into account that histones are easily cross-linked or modified by polyamines in vitro, the possibility that they may be TGase substrates in vivo is discussed.

Regulation of a high-affinity diamine transport system in Trypanosoma cruzi epimastigotes

Trypanosoma cruzi epimastigotes take up exogenous [3H]putrescine and [3H]cadaverine by a rapid, high-affinity, transport system that exhibits saturable kinetics (putrescine K(m) 2.0 microM, V(max) 3.3 nmol/min per 10(8) cells; cadaverine K(m) 13.4 microM, V(max) 3.9 nmol/min per 10(8) cells). Putrescine transport is temperature dependent and requires the presence of a membrane potential and thiol groups for activity. Its activity is altered in response to extracellular putrescine levels and as the cells proceed through the growth cycle. This transporter shows high specificity for the diamines putrescine and cadaverine, but low specificity for the polyamines spermidine and spermine. The existence of rapid diamine/polyamine transport systems whose activity can be adjusted in response to the growth conditions is of particular importance, as they seem unable to synthesize their own putrescine [Hunter, Le Quesne and Fairlamb (1994) Eur. J. Biochem. 226, 1019-1027].

First report of the inhibition of arbuscular mycorrhizal infection of Pisum sativum by specific and irreversible inhibition of polyamine biosynthesis or by gibberellic acid treatment

DFMO (alpha-DL-difluoromethylornithine), a specific irreversible inhibitor of ornithine decarboxylase (ODC), a polyamine biosynthetic pathway enzyme, strongly inhibits root growth and arbuscular mycorrhizal infection of Pisum sativum (P56 myc+, isogenic mutant of cv. Frisson). This inhibition is reversed when exogenous polyamine (putrescine) is included in the DFMO treatment, showing that the effect of DFMO on arbuscular mycorrhizal infection is indeed due to putrescine limitation and suggesting that ODC may have a role in root growth and mycorrhizal infection. However, treatment with gibberellic acid (GA3) which increased root titers of polyamines strongly inhibited arbuscular mycorrhizal development. The possible role of polyamines in the regulation of the development of arbuscular mycorrhizal infection is discussed.

Improved metabolic action of a bacterial lysine decarboxylase gene in tobacco hairy root cultures by its fusion to a rbcS transit peptide coding sequence

The gene of a bacterial lysine decarboxylase (ldc) fused to a rbcS transit peptide coding sequence (tp), and under the control of the CaMV 35S promoter, was expressed in hairy root cultures of Nicotiana tabacum. The fusion of the ldc to the targeting signal sequence improved the performance of the bacterial gene in the plant cells in many respects. Nearly all transgenic hairy root cultures harbouring the 35S-tp-ldc gene contained distinctly higher lysine decarboxylase activity (from 1.5 to 30 pkat LDC per mg protein) than those which had been transformed with constructs in which the gene had been directly cloned behind the CaMV 35S promoter. The higher enzyme activity led to the accumulation of up to 0.7% cadaverine on a dry mass basis. In addition, part of the cadaverine pool was used for increased biosynthesis of anabasine, an alkaloid which was hardly detectable in control cultures. The best line contained anabasine levels of 0.5% dry mass, which could be further be enhanced by feeding of lysine.

Superoxide anion radical generation during the oxidation of various amines by diamine oxidase

Diamine oxidase (DAO) or histaminase is an enzyme which deaminates histamine and several aliphatic amines to their corresponding aldehydes. Hydrogen peroxide and ammonia are side products of this reaction. The purpose of the present work was to evaluate if determination of produced hydrogen peroxide reflects DAO activity or if intermediate formation of the superoxide radical could be a reason for lack of correspondence between oxygen uptake and hydrogen peroxide production at different pH. Superoxide radical formation was determined by cytochrome c reduction in the presence and absence of superoxide dismutase (SOD). Oxygen uptake was measured with an oxygen electrode and hydrogen peroxide production by a spectrophotometric method. At pH 6.6 there was no superoxide production, but at pH 7.4 there was some, and it increased markedly at pH 9.5. Oxygen uptake also increased with increasing pH, especially with histamine as substrate. These results lead us to suggest that the mechanism of action of DAO involves the intermediate generation of superoxide radicals.

Comparison of kinetic properties between plant and fungal amine oxidases

Kinetic properties of novel amine oxidases isolated from a mold Aspergillus niger AKU 3302 were compared to those of typical plant amine oxidase from pea seedling (EC 1.4.3.6). Pea amine oxidase showed highest affinity with diamines, such as putrescine and cadaverine, while fungal enzymes oxidized preferably n-hexylamine and tyramine. All enzymes were inhibited by carbonyl reagents, copper chelating agents, some substrate analogs and alkaloids, but there were quite significant differences in the sensitivity and inhibition modes. Aminoguanidine, which strongly inhibited pea amine oxidases showed only little effect on fungal enzymes. Substrate analogs such as 1.5-diamino-3-pentanone and 1-amino-3-phenyl-3-propanone, which were potent competitive inhibitors of pea amine oxidases, inhibited fungal enzymes much more weakly and non competitively. Also various alkaloids behaving as competitive inhibitors of pea amine oxidase inhibited the fungal enzymes non competitively. Very surprising was the potent inhibition of fungal enzymes by artificial substrates of pea amine oxidases, E- and Z-1,4-diamino-2-butene. The relationships between the different inhibition modes and possible binding at the active site are discussed.

Mechanism-based inactivation of porcine kidney diamine oxidase by 1,4-diamino-2-butene

Cis- and trans-1,4-diamino-2-butene are substrates and potent inactivators of porcine kidney diamine oxidase. Evidence from absorption and NMR spectra indicates that both are oxidized to pyrrole. Both substrates are irreversible mechanism-based inactivators of the enzyme, although the trans isomer is more potent and results in complete inactivation in a reaction which follows pseudo-first-order kinetics with an apparent Ki of 0.34 mM and a second-order inactivation constant of 500 M-1 s-1. Under the same conditions, 46% of the activity remains when the enzyme is reacted with cis-1,4-diamino-2-butene. Trans-4-amino-2-butenal, the product of oxidation of the trans diamine, has been synthesized and shown to undergo cyclization to pyrrole in a concentration-dependent manner, approaching second-order at low concentrations. Trans-4-amino-2-butenal is itself a potent irreversible inhibitor with IC50 of 2.5 microM. We propose that the irreversible inactivation by both cis- and trans-1,4-diamino-2-butene involves attack by a protein-based nucleophilic residue on the unsaturated aminoenal products of the enzymatic reactions, resulting in a covalent adduct. Cyclization of the cis-aminoenal to pyrrole is much more rapid than in the trans case, thus it is less available for inhibitory reaction with the protein.

Polyamines and ripening of photoreceptor outer segments in chicken embryos

Polyamines and their related monoacetyl derivatives were studied in rod outer segment (ROS) and cone outer segment (COS) of photoreceptor cells from chick embryo retina during eye development (7th-18th days). Putrescine was found to be necessary, in the second phase of retinogenesis, to sustain both ROS and COS differentiation and, after acetylation, gamma-aminobutyric acid synthesis. On the other hand, spermidine and even more spermine intervene in the third phase of development when photoreceptors mature. Moreover, the presence of N1-acetylspermidine already at the 7th day indicates that in the outer segment of photoreceptor cells too, as in the whole retina, putrescine synthesis comes about by two pathways. One pathway involves ornithine decarboxylase; the other, spermidine/spermine N1-acetyltransferase and FAD-dependent polyamine oxidase activities that convert spermidine to putrescine via N1-acetylspermidine. These different biosynthetic pathways are probably also decisive in permitting gamma-aminobutyric acid synthesis, which is very important in the ripening process of neural retina.

Transglutaminase-catalyzed cross-linking of fibrils of collagen V/XI in A204 rhabdomyosarcoma cells

Collagens V and XI are thought to form a core around which the major interstitial collagens, I and II, respectively, are organized during fibrillogenesis. We previously reported the presence of a heterotypic form of collagens V and XI, [alpha 1(XI)]2 alpha 2(V), in cultures of A204 rhabdomyosarcoma cells [Kleman, J.-P., Hartmann, D. J., Ramirez, F., & van der Rest, M. (1992) Eur. J. Biochem. 210, 329-335]. This collagen forms a matrix which remains highly insoluble, even when cells were cultured in the presence of beta-aminopropionitrile, an inhibitor of lysyl oxidase and thereby of "classical" collagen cross-linking. When the cells were cultured in the presence of putrescine, a competitive inhibitor of transglutaminase-catalyzed protein cross-linking, a drastic increase in collagen solubility was observed. This result indicates that a transglutaminase contributes to the covalent stabilization of the collagen matrix of these cells. A204 rhabdomyosarcoma cells express tissue transglutaminase as revealed by specific antibodies, and enzyme activity was detected in the cell layer during culture and in cell extracts. Both collagens V and XI are specific glutaminyl substrates for tissue transglutaminase in vitro, as shown by incorporation of [3H]putrescine. The highly homologous alpha 1 chains of collagens V and XI were the major targets for the cross-linking. Trypsin cleaved the [3H] label from the alpha 1 chain of collagen V, demonstrating that the cross-linking occurs in the non triple helical propeptide domains.

Identification of factor-XIIIa-reactive glutaminyl residues in the propolypeptide of bovine von Willebrand factor

von Willebrand factor is a large multimeric plasma protein which plays important roles in platelet aggregation, blood coagulation and probably also in the adhesion of endothelial cells. A 100-kDa propeptide, called the propolypeptide of von Willebrand factor (pp-vWF), is generated during biosynthesis. We found that pp-vWF served as a substrate for transglutaminases including human factor XIIIa and guinea pig liver transglutaminase [Usui, T., Takagi, J. & Saito, Y. (1993) J. Biol. Chem. 268, 12311-12316]. As such, it could form cross-linked copolymers with the extracellular matrix protein, laminin, making it all the more likely that pp-vWF plays a role in cell adhesion phenomena [Takagi, J., Sudo, Y., Saito, T. & Saito, Y. (1994) Eur. J. Biochem. 222, 861-867]. In this work, we identified the Gln residues in pp-vWF specifically reacting with blood coagulation factor XIIIa as amine acceptors. The fluorescent amine, dansylcadaverine, was employed for labeling the enzyme-reactive sites of the protein. Following partial proteolysis, fragments containing the labeled Gln residues were isolated by passage through an anti-dansyl affinity chromatographic column. Amino acid sequence analyses of the fragments revealed that, out of about 40 Gln residues in pp-vWF, only four could be modified in the factor-XIIIa-catalyzed reaction.

The inter-relationship between polyamines and the L-arginine nitric oxide pathway in the human placenta

Nitric oxide (NO) and polyamines are both products of L-arginine metabolism. In placental villous tissue NO and polyamines have been shown to be synthesized although the physiological significance is not known. We have measured polyamine (putrescine, spermidine and spermine) concentrations and nitric oxide synthase activities (NOS) in first trimester and term placentae from normal and abnormal pregnancies, but no difference was observed in polyamine concentrations between normal term and placentae from growth-retarded and pre-eclamptic pregnancies. Significantly higher levels of polyamines were found in first trimester when compared to normal term placentae and there was a significant correlation between NOS activity and the cellular polyamine levels. Cultures of a trophoblast cell line, BeWo, have been used to study the interaction of added polyamines on NOS activity. Although there was a general tendency for all the polyamines to inhibit NOS activity only putrescine was able to significantly inhibit NO production by these cells. It is thought that the L-arginine-NO-polyamine pathway may have a physiological role during pregnancy.

The formation of biogenic amines by fermentation organisms

A total of 523 strains representing 35 species related to food fermentation organisms of practical importance were investigated for their potential for formation of biogenic amines (BA). The investigation was performed with resting cells in phosphate buffer (pH 5.5) and the formation of the following BAs was followed: putrescine, cadaverine, histamine, tyramine and 2-phenylethylamine. No potential was observed in species of lactococcus, Leuconostoc, Pediococcus, Streptococcus and several Lactobacillus spp., such as L. Pentosus and L. sake. A remarkable potential to form BA was observed in strains of carnobacteria, Lactobacillus buchneri, L. curvatus, L. reuteri, Staphylococcus carnosus and, to a lesser extent, in L. alimentarius, L. brevis, L. bavaricus, L. delbrueckii ssp. lactis, Micrococcus spp. and S. piscifermentans. In well known species with a practical function in the fermentation of dairy products, wine or cabbage a potential was observed for few strains only. In view of their role as starters in food fermentation, or their potential use in protective cultures and as probiotics, BA formation by the organisms has to be taken into consideration by selecting appropriate strains.

Transglutaminase-catalyzed matrix cross-linking in differentiating cartilage: identification of osteonectin as a major glutaminyl substrate

The expression of tissue transglutaminase in skeletal tissues is strictly regulated and correlates with chondrocyte differentiation and cartilage calcification in endochondral bone formation and in maturation of tracheal cartilage (Aeschlimann, D., A. Wetterwald, H. Fleisch, and M. Paulsson. 1993. J. Cell Biol. 120:1461-1470). We now demonstrate the transglutaminase reaction product, the gamma-glutamyl-epsilon-lysine cross-link, in the matrix of hypertrophic cartilage using a novel cross-link specific antibody. Incorporation of the synthetic transglutaminase substrate monodansylcadaverine (amine donor) in cultured tracheal explants reveals enzyme activity in the pericellular matrix of hypertrophic chondrocytes in the central, calcifying areas of the horseshoe-shaped cartilages. One predominant glutaminyl substrate (amine acceptor) in the chondrocyte matrix is osteonectin as revealed by incorporation of the dansyl label in culture. Indeed, nonreducible osteonectin-containing complexes of approximately 65, 90, and 175 kD can be extracted from mature tracheal cartilage. In vitro cross-linking of osteonectin by tissue transglutaminase gives similar products of approximately 90 and 175 kD, indicating that the complexes in cartilage represent osteonectin oligomers. The demonstration of extracellular transglutaminase activity in differentiating cartilage, i.e., cross-linking of osteonectin in situ, shows that tissue transglutaminase-catalyzed cross-linking is a physiological mechanism for cartilage matrix stabilization.

Diamine-oxidase activity and tissue di- and poly-amine contents of human ovarian, cervical and endometrial carcinoma

In view of the conflicting reports regarding the association of di- and poly-amines along with diamine oxidase (DAO) activity in human carcinomatous growths, the present study was undertaken to establish their interrelation and to justify whether analysis of di- and poly-amine contents along with DAO may have any diagnostic value in the assessment of the carcinomatous state. It was found that diamines like histamine, putrescine and cadaverine, and polyamines like spermine and spermidine, and also DAO, increased unequivocally in human ovarian, cervical and endometrial carcinoma in comparison with their adjoining normal tissues. A reasonable explanation has been put forward to support the observations made.

Regulation of the efflux of putrescine and cadaverine from rapidly growing cultured RAW 264 cells by extracellular putrescine

Cultures of the macrophage-like RAW 264 cells were adapted to divide normally in a synthetic serum-supplemented culture medium lacking any polyamines and diamine oxidase activity. These rapidly dividing cells actively effluxed large amounts of putrescine and cadaverine, compared with the intracellular levels, into the culture medium. The efflux of putrescine was stimulated by the amino acid ornithine, whereas efflux of cadaverine was inhibited. Relatively low levels of spermidine and N1-acetyl-spermidine, compared with those of exported putrescine, were observed to accumulate in the culture medium. A careful analysis of the changes in the intracellular concentration of putrescine relative to the steady-state net rate of putrescine export, as the doubling time of the cultures increased from 16 h to 22 h, indicated that an inverse relationship existed between these two parameters. As the intracellular putrescine concentrations increased, the net rate of putrescine export decreased markedly. Determination of the rate of putrescine uptake indicated that putrescine uptake also decreased significantly as the cultures neared confluency, and at no time during the growth of the culture did the rate of putrescine uptake approximate to the high rate of putrescine efflux. The decrease in the putrescine export rate seen as the cells grew toward confluency was determined to be primarily due to the inhibitory effect of the effluxed putrescine in the medium (Ki = 2 microM), and not to contact inhibition. The data suggested that the efflux of putrescine and cadaverine is not mediated to a significant degree by a process involving simple diffusion.

Characterization of putrescine and cadaverine export in mammalian cells. A pharmacological approach

We characterized the mechanism(s) involved in the efflux of putrescine/cadaverine from cultured mammalian cells using various pharmacological agents. Verapamil and quinine inhibited putrescine and cadaverine export in monocytic-leukemic RAW 264 and H35 hepatoma cells in a concentration-dependent manner with an IC50 in the micromolar range. Verapamil, which inhibits L-type calcium channels, inhibited putrescine export, regardless of whether calcium was present in the extracellular medium or not. Furthermore, the export of putrescine in the absence of verapamil did not appear to depend upon extracellular calcium. Neither intracellular calcium, external sodium, changes in intracellular pH nor phosphorylation affected the levels of putrescine export independently from changes in intracellular putrescine levels. The data suggest that verapamil and quinine inhibit putrescine/cadaverine efflux from the cell by binding directly to an integral membrane protein.

Identification and biosynthesis of N1,N9-bis(glutathionyl)aminopropylcadaverine (homotrypanothione) in Trypanosoma cruzi

Radiolabelling studies using tritiated ornithine, arginine and lysine, together with the relevant amino acid decarboxylase enzyme assays, indicate that the epimastigote stage of Trypanosoma cruzi is unable to synthesise significant amounts of putrescine and cadaverine de novo, compared to the amounts of these diamines scavenged from the growth medium. Radiolabelled putrescine is readily incorporated into spermidine, spermine and the trypanosomatid-specific polyamine-glutathione conjugate trypanothione (N1,N8-bis(glutathionyl)spermidine). Likewise, radiolabelled cadaverine is incorporated into the analogous polyamines aminopropylcadaverine, bis(aminopropyl)cadaverine and another major unidentified component. Subsequent studies showed this major component to be a novel polyamine-thiol conjugate whose structure was confirmed by chemical synthesis to be N1,N9-bis(glutathionyl)aminopropylcadaverine (homotrypanothione). Kinetic analyses using recombinant T. cruzi trypanothione reductase demonstrated that homotrypanothione disulphide is readily reduced by this enzyme with kinetic parameters similar to trypanothione disulphide, suggesting that it is a physiological substrate in vivo. Thus the epimastigote form of T. cruzi differs significantly from the African trypanosomes and Leishmania in (a) being unable to synthesise significant amounts of diamines de novo, (b) converting significant amounts of putrescine and cadaverine to spermine and bis(aminopropyl)cadaverine, respectively and (c) the ability to synthesise homotrypanothione as well as trypanothione. The implications of these findings with respect to the prospective chemotherapy of Chagas' disease are discussed.

A microtiter assay for factor XIII using fibrinogen and biotinylcadaverine as substrates

Efforts to develop an improved assay for plasma and tissue transglutaminase have led us to a convenient, sensitive microtiter plate assay for coagulation factor XIII using human fibrinogen as an immobilized substrate. Factor XIII was activated in the presence of calcium, thrombin, and immobilized fibrinogen and then assayed by adding biotinylcadaverine. The reaction was terminated by adding EDTA and the level of incorporated biotin was measured with streptavidin-beta-galactosidase. In this assay, the analytical range for human platelet factor XIII was 0.01-100 ng and 1-100 ng for guinea pig liver transglutaminase. Fibrinogen-coated plates gave more than 100-fold increase in sensitivity compared with N,N-dimethylcasein-coated microtiter plates. The intraassay coefficient of variation was less than 5% (n = 12) and interassay less than 6% (n = 4). The sensitivity of this assay reduced the volumes of plasma samples required and consequently eliminated the need to remove fibrinogen from such test samples. As expected, factor XIII activity could be inhibited by putrescine and antibodies against factor XIII as well as by a monoclonal antibody that bound to the carboxyl terminus of human fibrin gamma-chains. The assay provided a sensitive, simple, and rapid method for measuring factor XIII.

Photometric estimation of cadaverine oxidation by copper amine oxidase

A simple method for the photometric estimation of 1-piperideine, produced by the action of copper amino oxidases on cadaverine, is described. A discussion on the formation of 1-piperideine from lysine in acidic medium is also reported, together with some observations on the nature of acid 1-piperideine-ninhydrin condensation product.

Gln5 selectively monodansylated substance P as a sensitive tool for interaction studies with membranes

Substance P (SP) is a neuropeptide endowed with several important biological activities both in the central and peripheral nervous system. Taking advantage of the presence of glutamine residues in SP, the peptide was labelled with the fluorescent probe monodansylcadaverine using the transglutaminase (TGase)-reaction in order to study interactions between SP and model or natural membranes. Although it was verified that both adjacent glutamines of the peptide can act as substrate for TGase in a consecutive reaction, conditions were optimized to selectively label Gln5. This fluorescent SP analogue was found to adopt environment-dependent conformations similar to those of the natural peptide and proved to be functionally active on guinea pig trachea. Fluorescence spectroscopy was used to demonstrate the potential use of dansylated SP in studies involving interactions with membranes.

Cadaverine as a putative component of oral malodor

Whereas previous studies have shown correlations between volatile sulphur compounds (VSC) and bad breath levels, it is probable that other compounds found in the oral cavity may contribute to oral malodor. In the present investigation, the possibility that diamines (cadaverine and putrescine) are associated with oral malodor parameters was assessed. Saliva samples from 52 subjects were analyzed for cadaverine and putrescine by HPLC. Oral malodor of whole mouth, tongue, and saliva of the subjects was recorded by an experienced judge on a continuous 10-cm scale; peak and steady-state VSC intraoral levels were measured by the Interscan 1170 sulphide monitor. Log-transformed VSC and diamine levels were compared with odor judge measurements by Pearson analysis and stepwise forward multiple regression. Putrescine scores were not significantly associated with odor judge parameters or with VSC levels (p > 0.1). However, highly significant correlations (p < or = 0.003) were found between cadaverine levels and all three odor judge assessments. In contrast, associations between cadaverine and VSC measurements were non-significant. In an attempt to correlate odor judge results in terms of both VSC and diamines, we carried out stepwise forward multiple regression. Results showed that VSC and cadaverine both factor significantly in explaining each of the odor judge measurements, with multiple r values ranging from 0.545 (p = 0.0002) to 0.604 (p < 0.0001). The results suggest that cadaverine levels are associated with oral malodor, and that this association may be independent of VSC.

Biosynthesis and selective export of 1,5-diaminopentane (cadaverine) in mycoplasma-free cultured mammalian cells

Macrophage-like RAW 264 and H35 hepatoma cells grown under serum-free conditions exported putrescine and an unidentified diamine into the culture medium. Unlike putrescine, the unknown compound could be detected only extracellularly. Analyses of dansylated polyamine standards and mass spectroscopy confirmed that the unknown compound was cadaverine (1,5-diaminopentane). The cells were free of mycoplasma as evidenced by a negative result using a probe specific for prokaryotic rRNA. After prophylactic treatments with two different mycoplasmacidal agents, the cells continued to export cadaverine. Attempts to "infect" a noncadaverine-exporting cell line with culture medium and cell-free lysates proved unsuccessful, establishing that cadaverine was in fact a bona fide product of these mammalian cells. Cadaverine export by RAW 264 and H35 cells was stimulated by lipopolysaccharide and insulin, respectively. However, administration of exogenous ornithine caused cadaverine export to decrease significantly with concomitant increases in putrescine export. alpha-Difluoromethylornithine, a selective inhibitor of ornithine decarboxylase, inhibited both cadaverine and putrescine export. When cells were labeled with [3H]lysine, the great majority of the radioactivity recovered in exported polyamines was found in cadaverine. The cumulative data suggested that cadaverine formation may be caused by the action of intracellular ornithine decarboxylase upon lysine to produce cadaverine, which is then effluxed from the cell with a high degree of efficiency.

Escherichia coli cad operon functions as a supplier of carbon dioxide

We examined the gene expression of the Escherichia coli cad operon, which consisted of the genes cadB and cadA (lysine decarboxylase), using cells possessing cadB-lacZ fusion gene. The cad operon was expressed when O2 was limited, and the expression was optimal at pH 6.3. The beta-galactosidase activity was lowered by the addition of sodium carbonate to the medium. The expression of the cad operon was reduced in cells containing the plasmid-encoding ornithine decarboxylase, which produced carbon dioxide, indicating that the gene expression of the cad operon was regulated by carbon dioxide (or its derivatives). It is known that the Krebs cycle is a major pathway for producing carbon dioxide, and that its activity is repressed when O2 is limited. Thus, our present results suggested that the physiological role of the cad operon is to supply carbon dioxide when its internal level is lowered under O2-limiting conditions at a low pH.

Purification and characterization of amine oxidase from soybean seedlings

A simple and rapid procedure for purification of soybean seedling amine oxidase is reported. The crude enzyme, obtained by ammonium sulfate fractionation was purified by ion-exchange chromatography on a cellulose phosphate column and batch affinity chromatography on 6-aminohexyl-Sepharose. Cyclohexylamine, a competitive inhibitor, was utilized to elute the enzyme. A homogeneous enzyme was obtained with a yield higher than 25%, the content of minor components being < or = 2%. The M(r) estimated by gel filtration is 113,000 and 77,000 by sodium lauryl sulfate-polyacrylamide gel electrophoresis. The enzyme is a dimer and contains two Cu2+ ion per molecule. Its EPR spectrum is typical of Cu2+ in a tetragonal symmetry. The enzyme oxidizes cadaverine at high rate, the specific activity being 4.3 mukat/mg. Molecular, spectroscopic, and kinetic properties of this enzyme are reported.

Purification and characterization of homospermidine synthase in Acinetobacter tartarogenes ATCC 31105

Homospermidine synthase, catalyzing the formation of homospermidine [H2N(CH2)4NH-(CH2)4NH2] from putrescine and NAD+ with concomitant liberation of NH3, was purified 600-fold over the crude extract with a yield of about 14% to homogeneity from Acinetobacter tartarogenes ATCC 31105. The enzyme had a native molecular mass of 102 kDa, with a pI of 5.0, and was apparently composed of two identical subunits (52 kDa), suggesting that a single protein catalyzes two serial reactions, oxidation of putrescine to 4-aminobutyraldehyde and subsequent reduction of the putative Schiff base formed between this aldehyde and a second molecule of putrescine to homospermidine. The Km values for putrescine and NAD+ were 280 and 18 microM, respectively. 1,3-Diaminopropane and cadaverine were inactive as substrates, and NAD+ could not be replaced by NADP+. 1,3-Diaminopropane and NADH were potent competitive inhibitors. The enzyme had a pH optimum of 8.7, was most active at 30 degrees C, and required K+ and dithiothreitol for full activity. Putrescine and NAD+ protected the enzyme from the inhibition by thiol reagents. The NH2-terminal amino acid sequence was AQWPVYGKISGPVVI. Some of these properties were compared with those of the homospermidine synthases from a photosynthetic bacterium, Rhodopseudomonas viridis and a plant, Lathyrus sativus.

Hydroxyl radical production in the reactions of copper-containing amine oxidases with substrates

Solutions of porcine kidney diamine oxidase, PKDAO, and bovine plasma amine oxidase, BPAO, were saturated with the spin-trapping agent alpha-phenyl-N-t-butylnitrone, PBN, and incubated with cadaverine or benzylamine substrate, respectively, under aerobic conditions. EPR spectra due to trapped hydroxyl radicals were obtained for both enzymes with no evidence of superoxide formation. Under anaerobic conditions, hydroxyl radicals were formed only when H2O2 was present as well as substrate. Catalase prevented hydroxyl radical formation by PKDAO but not BPAO. The results indicate that hydroxyl radical is produced in the reaction of the product H2O2 with the reduced enzymes and therefore may be important in turnover-related enzyme degradation, but is not a true reaction intermediate.

Synthesis and use of fluorescent molecular probes for measuring cell-surface enzymatic oxidation of amino acids and amines in seawater

A method for investigating cell-surface enzymatic oxidative deamination of amino acids and amines in seawater was developed. This technique used synthetic fluorescent Lucifer Yellow derivatives of the amino acid lysine and the amine cadaverine as molecular probes to investigate oxidation pathways and rates. The probes were chemically stable under the conditions used and did not adsorb to container surfaces. The oxidative deamination of the fluorescent probes added to phytoplankton cultures and the subsequent production of their fluorescent oxidation products could be selectively detected by HPLC at 250 pM levels. This approach allows selective investigation of cell-surface enzymatic oxidation since neither transport of the probes across the cell membrane nor chemical transformation of the probes occurs. Bacteria were also capable of oxidizing the fluorescent amino acid probe.