Tlc silica gel 60g f254

TLC with sulfate or thiobarbituric acid staining was conducted as described previously^{16 (link)}. Briefly, the reaction mixture (5.0 µL) was spotted on TLC Silica Gel 60G F₂₅₄ (Merck, Darmstadt, Germany), which was developed using a solvent system of 1-butanol/acetic acid/water (3/2/2, v/v/v), and results were visualized by spraying the gels with 10% sulfuric acid in ethanol (sulfic acid staining) or thiobarbituric acid staining, followed by heating. Then, authenticating DEH [5.0 µL of 1% (w/v)] or 2-keto-3-deoxy-d-gluconate [1% (w/v)] was spotted on the gels.

¹H and ¹³C NMR spectra were recorded at 500 MHz using a JEOL JNM-ECZ500R/S1 instrument. Infrared (IR) spectra were measured with an FTIR, IRPrestige-21, Shimadzu. Other analyses were performed using a Waters UPLC-MS XEVO G2-XS QTof instrument, a VersaMax Microplate reader and a BioTek ELX800 Microplate reader, pre-coated aluminum sheets TLC-Silica gel 60 GF254 (Merck, Darmstadt, Germany), column chromatography (CC) was performed using Silica gel 60 (Merck, Darmstadt, Germany) with 70–230 mesh for open chromatography and 230–400 mesh for vacuum chromatography.

The detection of BAs was carried out using TLC as described by Latorre-Moratalla et al. [49 (link)] with slight modifications. Briefly, EFEL7002 was sub-cultured four times in MRS medium containing 6% (w/v) NaCl and 0.1% of the amino acid precursors (w/v) (L-tyrosine freebase, L-histidine monochlorohydrate, L-ornithine monochlorohydrate, L-tryptophan, L-lysine monochlorohydrate, L-phenylalanine, and L-arginine (Sigma-Aldrich, St. Louis, MO, USA)) at 37 °C for 24 h. Then, the bacterial culture was centrifuged at 10,000×g at 4 °C for 10 min, and the supernatant was filtered using a 0.22 μm microfilter membrane (Polypropylene, Whatman, Kent, UK). The BAs produced were detected by a UV lamp in TLC (TLC silica gel 60G F₂₅₄; Merck, Darmstadt, Germany) by neutralizing the sample with NaHCO₃ and derivatizing it with dansyl chloride. A standard solution containing eight BAs (tyramine, histamine, phenylethylamine, tryptamine, putrescine, cadaverine, spermine, and spermidine) was used as the detection control.