Ashby K D, Casey T A, Rasmussen M A, Petrich J W
Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA.
J Agric Food Chem. 2001 Mar;49(3):1123-7. doi: 10.1021/jf000689r.
Methanogenic bacteria, which are common inhabitants of the animal digestive tract, contain the fluorescent compound F420 (coenzyme 420), a 7,8-didemethyl-8-hydroxy-5-deazariboflavin chromophore. F420 was characterized as an initial step in determining if this compound would be useful as a fluorescent marker for the detection of fecal and ingesta contamination. Using a single anion exchange chromatographic process, F420 was separated from other cell components of a Methanobrevibacter sp. cell culture. The extent of separation was determined spectroscopically. To aid in the development of possible techniques for the detection of fecal contamination using F420 as a marker, further spectroscopic investigation of F420 was conducted using steady-state and time-resolved fluorescence methods. The fluorescence lifetime of F420 in an elution buffer of pH 7.5 was found to be 4.2 ns. At higher pH values, the fluorescence decay, F(t), was best described by a sum of two exponentials: at pH 13, F(t) = 0.31 exp(-t/4.20 ns) + 0.69 exp(-t/1.79 ns). Further investigation using front-faced fluorescence techniques has shown that emission from F420 can be collected efficiently from samples of methanogen cell cultures as well as from fecal material.
产甲烷菌是动物消化道的常见栖居菌，含有荧光化合物F420（辅酶420），一种7,8-二去甲基-8-羟基-5-去氮杂黄素发色团。F420被鉴定是确定该化合物是否可用作检测粪便和食糜污染的荧光标记的第一步。使用单一阴离子交换色谱法，从短双歧杆菌属细胞培养物的其他细胞成分中分离出F420。通过光谱法测定分离程度。为了帮助开发可能的使用F420作为标记检测粪便污染的技术，使用稳态和时间分辨荧光方法对F420进行了进一步的光谱研究。发现F420在pH 7.5的洗脱缓冲液中的荧光寿命为4.2纳秒。在较高pH值下，荧光衰减F(t)最好用两个指数之和来描述：在pH 13时，F(t)=0.31 exp(-t/4.20纳秒)+0.69 exp(-t/1.79纳秒)。使用前表面荧光技术的进一步研究表明，可以从产甲烷菌细胞培养物样品以及粪便物质中有效收集F420的发射光。
