Comprehensive analysis of polyamine transport and biosynthesis in the dominant human gut bacteria: Potential presence of novel polyamine metabolism and transport genes

The Biology of Glial Cells and Their Complex Roles in Alzheimer’s Disease: New Opportunities in Therapy

“…In contrast, it is noteworthy to point out that over accumulation of hydrogen peroxide, which may be released in several stress situations, and PAs may lead to cell death [ 159 , 166 , 167 , 168 ]. However, this should not deviate from the fact that PAs may actually have several important roles to play in AD progression [ 163 , 169 ].…”

Bioactive polyamine production by a novel hybrid system comprising multiple indigenous gut bacterial strategies

“…Two metabolic pathways for the conversion of agmatine to putrescine have been reported to date: The first is the agmatine ureohydrolase (SpeB) pathway, where agmatine is directly converted to putrescine; the second is the N -carbamoylputrescine pathway, which involves N -carbamoylputrescine production from agmatine by agmatine iminohydrolase and its conversion to putrescine by N -carbamoylputrescine amidohydrolase. In silico genome analysis of the 56 most abundant bacterial species in the human microbiome ( 16 ) has predicted that many species are unable to produce putrescine from arginine using their own enzymes, owing to incomplete synthetic pathways ( 17 , 18 ), in turn suggesting the existence of a metabolic pathway spanning multiple bacterial species in the gut. However, to our knowledge, there currently is no genetic proof for such a hybrid metabolic pathway.…”

Biosynthesis of Putrescine from L-arginine Using Engineered Escherichia coli Whole Cells

“…To evaluate the effect of temperature on biotransformation, the reaction was carried out at 20, 30, 40, 50, and 60 • C. In order to evaluate the influence of pH, the pH of the reaction system was adjusted to 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, or 11.0 (50 mM KH 2 PO 4 -NaOH buffer for pH 6.5-8.0, 50 mM Tris-HCl buffer for pH 8.0-9.0, 50 mM glycine-NaOH buffer for pH 9.5-10.0, KCl-NaOH buffer for pH 11.0). Different concentrations of L-arginine (5,10,20,30, and 40 mM) were used to determine the optimal substrate concentration. All reactions were carried out in triplicate.…”

“…In mammals, putrescine regulates the intestinal flora and improves the intestinal immune function [4]. Putrescine is also an important metabolite of the human intestinal flora, which is crucial to their life processes [5]. Treating plants with putrescine positively affects their growth, productivity, and stress tolerance [6].…”