Synthesis and scavenging role of furan fatty acids

Abstract

Fatty acids play important functional and protective roles in living systems. This paper reports on the synthesis of a previously unidentified 19 carbon furan-containing fatty acid, 10,13-epoxy-11-methyl-octadecadienoate (9-(3-methyl-5-pentylfuran-2-yl)nonanoic acid) (19Fu-FA), in phospholipids from Rhodobacter sphaeroides. We show that 19Fu-FA accumulation is increased in cells containing mutations that increase the transcriptional response of this bacterium to singlet oxygen ( 1 O 2 ), a reactive oxygen species generated by energy transfer from one or more light-excited donors to molecular oxygen. We identify a previously undescribed class of S-adenosylmethionine-dependent methylases that convert a phospholipid 18 carbon cis unsaturated fatty acyl chain to a 19 carbon methylated trans unsaturated fatty acyl chain (19M-UFA). We also identify genes required for the O 2 -dependent conversion of this 19M-UFA to 19Fu-FA. Finally, we show that the presence of 1 O 2 leads to turnover of 19Fu-Fa in vivo. We propose that furan-containing fatty acids like 19Fu-FA can act as a membrane-bound scavenger of 1 O 2 , which is naturally produced by integral membrane enzymes of the R. sphaeroides photosynthetic apparatus.radical scavenger | oxygenated fatty acid | fatty acyl methylase

Antimicrobial photodynamic activity and cytocompatibility of Au₂₅(Capt)₁₈ clusters photoexcited by blue LED light irradiation

“…Recently, a captopril-protected gold cluster, consisting of 25 gold atoms and 18 captopril ligands as the protector, Au 25 (Capt) 18 , was developed as a novel photosensitizer not categorized as a conventional organic dye photosensitizer. 19 The Au 25 (Capt) 18 cluster measures 0.9 nm in diameter; is highly stable, less degradable, and water-soluble; and produces 1 O 2 on near-infrared light irradiation.…”

“…19 The Au 25 (Capt) 18 cluster measures 0.9 nm in diameter; is highly stable, less degradable, and water-soluble; and produces 1 O 2 on near-infrared light irradiation. Thus, Au 25 (Capt) 18 clusters may resolve the problems associated with organic dye photosensitizers for aPDT. We speculated that Au clusters may possess new characteristics for dental aPDT compared with conventional photosensitizers.…”

“…We speculated that Au clusters may possess new characteristics for dental aPDT compared with conventional photosensitizers. In addition to the near-infrared region, Au 25 (Capt) 18 clusters have stronger absorbance in the range of 300-500 nm with a peak at 450 nm. 19 Thus, we anticipated that Au 25 (Capt) 18 clusters photoexcited by a blue light-emitting diode (LED) light (ca.…”

“…In addition, Chui et al 20 reported that blue light irradiation effectively inhibited the viability of bacterial cells. Thus, the combination of Au 25 (Capt) 18 clusters and blue LED light is anticipated to exhibit synergistic antimicrobial effects. The local administration of Au clusters at the periodontal pocket or against root canal infection and subsequent LED irradiation may be a valuable antibacterial therapy in dentistry.…”

“…In this study, we report a new methodology for dental aPDT using Au 25 (Capt) 18 clusters photoexcited by blue LED light. We evaluated whether Au 25 (Capt) 18 clusters could produce 1 O 2 on blue LED light irradiation and exert antibacterial activity against oral bacterial cells, Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis.…”