RESUMO
A Gram-stain-negative, rod-shaped strain, Braz8T, isolated from larvae of Anopheles darlingi was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Braz8T was related most closely to species of the genus Thorsellia, with 95.6, 96.5 and 96.6 % similarity to the type strains of Thorsellia anophelis, Thorsellia kandunguensis and Thorsellia kenyensis, respectively, and formed a separate branch in the phylogenetic tree next to the monophyletic cluster of the genus Thorsellia. Chemotaxonomic data supported the allocation of the strain to the family Thorselliaceae. The major fatty acids were C18 : 1ω7c, C16 : 0 and C14 : 0. The quinone system was composed of ubiquinones Q-8 and Q-7 (1 : 0.3), the predominant polar lipids were diphosphatidylglycerol and phosphatidylglycerol, and the polyamine pattern showed the major compound putrescine. However, qualitative and quantitative differences in the major polyamine, polar lipid profile and fatty acid patterns distinguished strain Braz8T from species of the genus Thorsellia. Phylogenetic analysis based on 16S rRNA gene sequences, average nucleotide identity, DNA-DNA hybridization, multilocus sequence analysis as well as physiological and biochemical tests distinguished strain Braz8T both genotypically and phenotypically from the three Thorsellia species but also showed its placement in the family Thorselliaceae. Thus, strain Braz8T is considered to represent a novel species of a new genus most closely related to the genus Thorsellia, for which the name Coetzeea brasiliensis gen. nov., sp. nov. is proposed. The type strain of Coetzeea brasiliensis is Braz8T (=LMG 29552T=CIP 111088T).
Assuntos
Anopheles/microbiologia , Enterobacteriaceae/classificação , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Enterobacteriaceae/genética , Enterobacteriaceae/isolamento & purificação , Ácidos Graxos/química , Larva/microbiologia , Hibridização de Ácido Nucleico , Fosfolipídeos/química , Putrescina/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/químicaRESUMO
Spermine and spermidine are natural polyamines that are produced mainly via decarboxylation of l-ornithine and the sequential transfer of aminopropyl groups from S-adenosylmethionine to putrescine by spermidine synthase and spermine synthase. Spermine and spermidine interact with intracellular and extracellular acidic residues of different nature, including nucleic acids, phospholipids, acidic proteins, carboxyl- and sulfate-containing polysaccharides. Therefore, multiple actions have been suggested for these polycations, including modulation of the activity of ionic channels, protein synthesis, protein kinases, and cell proliferation/death, within others. In this review we summarize these neurochemical/neurophysiological/morphological findings, particularly those that have been implicated in the improving and deleterious effects of spermine and spermidine on learning and memory of naïve animals in shock-motivated and nonshock-motivated tasks, from a historical perspective. The interaction with the opioid system, the facilitation and disruption of morphine-induced reward and the effect of polyamines and putative polyamine antagonists on animal models of cognitive diseases, such as Alzheimer's, Huntington, acute neuroinflammation and brain trauma are also reviewed and discussed. The increased production of polyamines in Alzheimer's disease and the biphasic nature of the effects of polyamines on memory and on the NMDA receptor are also considered. In light of the current literature on polyamines, which include the description of an inborn error of the metabolism characterized by mild-to moderate mental retardation and polyamine metabolism alterations in suicide completers, we can anticipate that polyamine targets may be important for the development of novel strategies and approaches for understanding the etiopathogenesis of important central disorders and their pharmacological treatment.
Assuntos
Aprendizagem , Memória , Espermidina/química , Espermina/química , Animais , Sítios de Ligação , Disfunção Cognitiva/induzido quimicamente , Disfunção Cognitiva/fisiopatologia , Humanos , Aprendizagem/efeitos dos fármacos , Memória/efeitos dos fármacos , Putrescina/química , Putrescina/metabolismo , Ratos , Espermidina/metabolismo , Espermina/metabolismoRESUMO
The α-aminoketone 1,4-diamino-2-butanone (DAB), a putrescine analogue, is highly toxic to various microorganisms, including Trypanosoma cruzi. However, little is known about the molecular mechanisms underlying DAB's cytotoxic properties. We report here that DAB (pK(a) 7.5 and 9.5) undergoes aerobic oxidation in phosphate buffer, pH 7.4, at 37°C, catalyzed by Fe(II) and Cu(II) ions yielding NH(4)(+) ion, H(2)O(2), and 4-amino-2-oxobutanal (oxoDAB). OxoDAB, like methylglyoxal and other α-oxoaldehydes, is expected to cause protein aggregation and nucleobase lesions. Propagation of DAB oxidation by superoxide radical was confirmed by the inhibitory effect of added SOD (50 U ml-1) and stimulatory effect of xanthine/xanthine oxidase, a source of superoxide radical. EPR spin trapping studies with 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) revealed an adduct attributable to DMPO-HO(â¢), and those with α-(4-pyridyl-1-oxide)-N-tert-butylnitrone or 3,5-dibromo-4-nitrosobenzenesulfonic acid, a six-line adduct assignable to a DAB(â¢) resonant enoyl radical adduct. Added horse spleen ferritin (HoSF) and bovine apo-transferrin underwent oxidative changes in tryptophan residues in the presence of 1.0-10 mM DAB. Iron release from HoSF was observed as well. Assays performed with fluorescein-encapsulated liposomes of cardiolipin and phosphatidylcholine (20:80) incubated with DAB resulted in extensive lipid peroxidation and consequent vesicle permeabilization. DAB (0-10 mM) administration to cultured LLC-MK2 epithelial cells caused a decline in cell viability, which was inhibited by preaddition of either catalase (4.5 µM) or aminoguanidine (25 mM). Our findings support the hypothesis that DAB toxicity to several pathogenic microorganisms previously described may involve not only reported inhibition of polyamine metabolism but also DAB pro-oxidant activity.
Assuntos
Sobrevivência Celular/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Putrescina/análogos & derivados , Espécies Reativas de Oxigênio/química , Animais , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Linhagem Celular , Ferritinas/efeitos dos fármacos , Radicais Livres/análise , Radicais Livres/toxicidade , Haplorrinos , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Radical Hidroxila/química , Radical Hidroxila/metabolismo , Metais/química , Consumo de Oxigênio/efeitos dos fármacos , Poliaminas/química , Putrescina/química , Putrescina/farmacologia , Superóxidos/química , Superóxidos/metabolismo , Transferrina/efeitos dos fármacosRESUMO
Polyamine metabolism, as well as spermine (Spm) antioxidant properties, were studied in wheat leaves under Cd2+ or Cu2+ stress. The oxidative damage produced by both metals was evidenced by an increased of thiobarbituric acid reactive substances (TBARS) and a significant decrease in glutathione under both metal treatments. Ascorbate peroxidase (APOX) and glutathione reductase (GR) activities were reduced by both metals to values ranging from 30% to 64% of the control values. Conversely, copper produced a raise in superoxide dismutase activity. The high putrescine (Put) content detected under Cd2+ stress (282% over the control) was induced by the increased activity of both enzymes involved in Put biosynthesis, arginine decarboxylase (ADC) and ornithine decarboxylase (ODC). However, only ODC activity was increased in wheat leaves subjected to Cu2+ stress, leading to a lower Put rise (89% over the controls). Spermidine (Spd) content was not affected by metal treatments, while Spm was significantly reduced. Pretreatment with Spm completely reverted the metals-induced TBARS increase whereas metals-dependent H2O2 deposition on leaf segments (revealed using diaminobenzidine), was considerably reduced in Spm pretreated leaf segments. This polyamine failed to reverse the depletion in APOX activity and glutathione (GSH) content produced by Cd2+ and Cu2+, although it showed an efficient antioxidant behavior in the restoration of GR activity to control values. These results suggest that Spm could be exerting a certain antioxidant function by protecting the tissues from the metals-induced oxidative damage, though this effect was not enough to completely avoid Cd2+ and Cu2+ effect on certain antioxidant enzymes, though the precise mechanism of protection still needs to be elucidated.
Assuntos
Antioxidantes , Cádmio , Cobre/química , Folhas de Planta , Espermina , Antioxidantes/química , Antioxidantes/metabolismo , Ascorbato Peroxidases , Cádmio/química , Cádmio/metabolismo , Carboxiliases/metabolismo , Cobre/metabolismo , Glutationa/metabolismo , Glutationa Redutase/metabolismo , Peróxido de Hidrogênio/metabolismo , Ornitina Descarboxilase/metabolismo , Oxidantes/metabolismo , Oxirredução , Peroxidases/metabolismo , Folhas de Planta/química , Folhas de Planta/enzimologia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Putrescina/química , Putrescina/metabolismo , Espermina/química , Espermina/metabolismo , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , TriticumRESUMO
The effect of different doses of cadmium and copper was studied in relation to growth and polyamine (Pas) metabolism in shoots of sunflower plants. Cadmium accumulated to higher levels than copper and shoot length was reduced by 0.5 and 1 mM Cd, but only by 1 mM Cu. At 1 mM of Cd or Cu, Put content increased 270% and 160% with Cd2+ and Cu2+, respectively. Spermidine (Spd) was modified only by 1 mM Cd, while spermine (Spm) declined after seeds germinated, increasing thereafter but only with 1 mM Cd or Cu (273% over the controls for Cd and 230% for Cu at day 16). Both ADC and ODC activities were increased by 1 mM Cd, whereas 1 mM Cu enhanced ADC activity, but reduced ODC activity at every concentration used. The role of Pas as markers of Cd or Cu toxicity is discussed.
Assuntos
Cádmio/toxicidade , Cobre/toxicidade , Poliaminas/metabolismo , Amina Oxidase (contendo Cobre)/metabolismo , Carboxiliases/metabolismo , Clorofila/química , Clorofila/metabolismo , Cobre/química , Helianthus , Metais , Ornitina Descarboxilase/metabolismo , Poliaminas/química , Prolina/química , Putrescina/química , Espermidina/química , Espermina/química , Fatores de Tempo , Água/químicaRESUMO
This work describes the synthesis and characterization of six new dinuclear platinum complexes having N,N'-di-(2-aminoethyl)-1,3-diamino-2-propanol, aryl substituted N-benzyl-1,4-butanediamines and N-benzyl-1,6-hexanediamines as ligands. They were prepared by the reaction of cis-[PtCl(2)(DMSO)(2)] (DMSO=dimethyl sulfoxide) with the appropriate ligand in water, except for one of them, which was prepared from K(2)PtCl(4). We also report the cytotoxic activity and cellular accumulation of three of these complexes in a human small-cell lung carcinoma cell line and its resistant subline. Resistant cells exhibited a lesser degree of cross-resistance to these compounds when compared to cisplatin. The accumulation of platinum in both cell lines followed the same pattern, i.e. approximately the same intracellular platinum concentration yielded the same cytotoxic effect independent of the nature of the platinum complex used.
Assuntos
Compostos Organoplatínicos/síntese química , Compostos Organoplatínicos/toxicidade , Platina/metabolismo , Platina/toxicidade , Putrescina/análogos & derivados , Putrescina/química , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Resistencia a Medicamentos Antineoplásicos , Ligantes , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Compostos Organoplatínicos/química , Compostos Organoplatínicos/metabolismo , Platina/administração & dosagem , Platina/químicaRESUMO
NMR spectroscopy was used to characterize the binding properties of polyamines to Escherichia coli tRNA. The (15)N NMR spectra of three (15)N-enriched N-substituted putrescine derivatives (DMP, DEP and DBP) were recorded in the presence of tRNA, and the spin relaxation times of the nitrogen nuclei were measured. From these data, the activation parameters for the rotational correlation times of the (15)N nuclei were determined. The present data indicate that the nature of the amino substituents does play a relevant role in controlling the polyamine-tRNA interaction. This study also provides a rationale for the in vivo antiproliferative effect of DBP against tumoral cells.
Assuntos
Putrescina/análogos & derivados , RNA de Transferência/química , Espectroscopia de Ressonância Magnética , Conformação de Ácido Nucleico , Putrescina/química , RNA Bacteriano/químicaRESUMO
2-(Aminomethyl)-4-aminobutyric acid (isoornithine), 3-methylisoornithine, and 2,3-dimethylisoornithine were not decarboxylated by liver ornithine decarboxylase (ODC, EC 4.1.1.17) of thioacetamide-treated rats but were good competitive inhibitors of the enzyme (Ki ranged from 0.72 to 1.79 mM). When assayed in vivo in the treated rats, the above mentioned isoornithines were also found to inhibit liver ODC when administered 1 h before sacrifice. When the methylputrescines formally derived from the decarboxylation of several isoornithines were assayed on rat liver ODC, it was found that only 2,3-dimethylputrescine decreased the enzymatic activity. When assayed in vivo, it was found to decrease ODC activity by 60%, when the latter was measured 1 h after administration. The effect was reverted 4 h after administration of the drug. Isoornithines were not taken up by H-35 hepatoma cells; hence they did not affect their ODC activity. 2,3-Dimethylputrescine however, was transported into the cells and significantly decreased its ODC activity.
Assuntos
Inibidores Enzimáticos/farmacologia , Inibidores da Ornitina Descarboxilase , Ornitina/análogos & derivados , Ornitina/química , Putrescina/análogos & derivados , Putrescina/química , Animais , Ligação Competitiva , Carcinoma Hepatocelular , Fígado/efeitos dos fármacos , Fígado/enzimologia , Neoplasias Hepáticas , Ornitina/metabolismo , Putrescina/metabolismo , Ratos , Relação Estrutura-Atividade , Tioacetamida/farmacologia , Células Tumorais CultivadasRESUMO
15N NMR spectroscopy was used to explore the interactions between natural polyamines and Escherichia coli tRNA. It was found that when tRNA is added to solutions of 15N-labeled spermine or spermidine, there is a considerable decrease in the relative heights of the -NH(2+)--resonances with respect to the signals arising from the -NH3+ groups. The presence of tRNA was also found to reduce the longitudinal relaxation times T1 of the nitrogens, mainly those of the -NH(2+)- groups. The longitudinal relaxation times of the nitrogens were used to characterize the temperature dependence of the binding, and they allowed us to calculate the activation energies that determine the correlation times of amino groups in the presence of tRNA. Both the thermodynamic and the relaxation results indicate that (i) spermine binds more strongly to tRNA than spermidine does and (ii) within each of these molecules the -NH(2+)- groups bind more strongly to tRNA than the more electropositive -NH3+ moieties. This specificity suggests that the interaction between polyamines and tRNA cannot be described exclusively in terms of electrostatic forces and that other interactions (most likely, hydrogen bonding) are very important for establishing the polyamine-tRNA link. Some of the factors that may conspire against the binding of -NH3+ groups to tRNA are briefly discussed.