Effect of polyamines and synthetic polyamine-analogues on the expression of antizyme (AtoC) and its regulatory genes

Abstract

BackgroundIn bacteria, the biosynthesis of polyamines is modulated at the level of transcription as well as post-translationally. Antizyme (Az) has long been identified as a non-competitive protein inhibitor of polyamine biosynthesis in E. coli. Az was also revealed to be the product of the atoC gene. AtoC is the response regulator of the AtoS-AtoC two-component system and it functions as the positive transcriptional regulator of the atoDAEB operon genes, encoding enzymes involved in short chain fatty acid metabolism. The antizyme is referred to as AtoC/Az, to indicate its dual function as both a transcriptional and post-translational regulator.ResultsThe roles of polyamines on the transcription of atoS and atoC genes as well as that of atoDAEB(ato) operon were studied. Polyamine-mediated induction was tested both in atoSC positive and negative E. coli backgrounds by using β-galactosidase reporter constructs carrying the appropriate promoters patoDAEB, patoS, patoC. In addition, a selection of synthetic polyamine analogues have been synthesized and tested for their effectiveness in inducing the expression of atoC/Az, the product of which plays a pivotal role in the feedback inhibition of putrescine biosynthesis and the transcriptional regulation of the ato operon. The effects of these compounds were also determined on the ato operon expression. The polyamine analogues were also tested for their effect on the activity of ornithine decarboxylase (ODC), the key enzyme of polyamine biosynthesis and on the growth of polyamine-deficient E. coli.ConclusionPolyamines, which have been reported to induce the protein levels of AtoC/Az in E. coli, act at the transcriptional level, since they cause activation of the atoC transcription. In addition, a series of polyamine analogues were studied on the transcription of atoC gene and ODC activity.

A wide diversity of bacteria from the human gut produces and degrades biogenic amines

“…That drastic difference in histamine, spermidine and spermine concentrations may represent a system of regulation in the presence of one or several BAs. Very few data to date have suggested that BAs possess self-regulatory activities; however, it was demonstrated that the protein AtoC/Az (an ornithine decarboxylase inhibitor) from E. coli was regulated at a transcriptional level in the presence of BAs [36]. …”

Regulation of the Escherichia coli AtoSC two component system by synthetic biologically active 5;7;8-trimethyl-1;4-benzoxazine analogues

“…The ability of the previously synthesized constructs 11,21 carrying lacZ fused to either of the promoters of the atoSC system (i.e., the atoC and the atoDAEB promoter) to respond to the compounds of the present study was evaluated in E. coli strain BW25113 (Fig. 2).…”

“…9 We have recently reported the regulation of the AtoSC system by polyamines and histamine, as cellular components that enable pathogenic bacteria to survive and overcome host defence mechanisms. [10][11][12] Putrescine, the non-natural diamine 1,3-diaminopropane and their synthetic analogues elicited a pronounced atoC transcriptional activation, without activating neither the atoDAEB operon promoter nor atoS. 11 Histamine, a biogenic amine, elicited a polyamine-mediated inductive phenotype and induced atoC expression, without activating the atoDAEB operon promoter.…”

“…[10][11][12] Putrescine, the non-natural diamine 1,3-diaminopropane and their synthetic analogues elicited a pronounced atoC transcriptional activation, without activating neither the atoDAEB operon promoter nor atoS. 11 Histamine, a biogenic amine, elicited a polyamine-mediated inductive phenotype and induced atoC expression, without activating the atoDAEB operon promoter. 12 Furthermore, the involvement of TCSs including AtoSC, in specialized functions including the bacterial pathogenicity, virulence and host-microbe interactions 3,4 warrant the investigation of a number of synthetic amine-containing compounds, including 1,4-benzoxazines, on their possible involvement on the signaling cascade.…”

Effect of Xanthan and Arabic Gums on Foaming Properties of Pumpkin (Cucurbita pepo) Seed Protein Isolate

“…Due to the poly electrolyte nature of xanthan and Arabic gums (Makri & Doxastakis, 2006;Garcıá-Ochoa, Santos, Casas, & Gómez, 2000), the flexible film networks formed by the PSPI-XG/GA interactions around the bubbles in the solution could have been negatively affected by the addition of sodium chloride and may have contributed further to the repulsive forces resulting in reduced foaming properties. At lower pH conditions increase in NaCl concentration causes an increase in protein stability (Lindman et al, 2006), which results in unfolding, viscosity, solubility and aggregation of proteins, which in turn affect foaming properties by increasing the solvent surface tension,decreasing the solubility of nonpolar molecules and ultimately strengthening hydrophobic interactions (Cheftel et al, 1985;Mao, Sheng, & Pan, 2007). Therefore salt treatment conditions under much lower pH conditions could most likey improve the foaming properties.…”