Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

Abstract

HPLC/DAD-based chemical investigation of a coral-associated gliding bacterium of the genus Tenacibaculum yielded three desferrioxamine-class siderophores, designated tenacibactins K (1), L (2), and M (3). Their chemical structures, comprising repeated cadaverine–succinic acid motifs terminated by a hydroxamic acid functionality, were elucidated by NMR and negative MS/MS experiments. Compounds 1–3 were inactive against bacteria and a yeast but displayed cytotoxicity against 3Y1 rat embryonic fibroblasts and P388 murine leukemia cells at GI50 in submicromolar to micromolar ranges. Their iron-chelating activity was comparable to deferoxamine mesylate.

Amamistatins isolated from Nocardia altamirensis

“…The affinities of compound 1 – 6 for the coordination of ferric iron were evaluated with the CAS assay [ 9 ] and compared with EDTA [ 13 ]. While the half-maximal displacement concentration (DC 50 ) value of 5 (198 ± 10 μM) was comparable with EDTA (173 ± 6 μM), the other tested amamistatins were much weaker chelating agents ( 1 , 3359 ± 181 μM; 2 , 1074 ± 65 μM; 3 , 3268 ± 183 μM; 4 , 3298 ± 261 μM).…”

“…Previous studies have demonstrated that, in nature, hydroxamates arise from the oxidation of terminal amino groups in amino acid side chains, followed by formylation or acylation of the resulting hydroxylamines. While the oxidations are catalyzed by flavin-dependent monooxygenases [ 12 – 16 ], the carbon transfer is mediated either by tetrahydrofolate-dependent formyl [ 17 ] or by acyl-CoA-dependent acyl transferases [ 13 , 15 – 16 ]. It is widely assumed that the oxidation precedes the formylation or acylation [ 17 – 22 ].…”

Selenized glucose improves rat semen quality by improving the gut microbiota and serum metabolome

“…Tenacibaculum is a pathogenic bacterium toxic to rat embryonic cells. 41 Aeromonas is an opportunistic bacterium that causes infection of the intestinal mucosa. 42 Endotoxins produced by intestinal bacterial infections may inhibit steroid hormone synthesis in Leydig cells, decreasing testosterone secretion.…”

Marine natural products

“…Hydroxamate-containing siderophores, tenacibactins K–M 194 – 196 were isolated from a coral-derived Tenacibaculum sp., with 196 showing moderate activity against rat embryonic fibroblasts and the P388 murine leukemia cell line. 58 …”