Conklin Sean D, Ackerman Amanda H, Fricke Michael W, Creed Patricia A, Creed John T, Kohan Michael C, Herbin-Davis Karen, Thomas David J
US EPA, ORD, NERL, Microbiological and Chemical Exposure Assessment Research Division, Cincinnati, OH 45268, USA.
Analyst. 2006 May;131(5):648-55. doi: 10.1039/b516275k. Epub 2006 Mar 9.
This investigation examined chemical and microbiological transformations of an arsenosugar by mouse cecum. To mimic the low oxygen environment in the mammalian gastrointestinal tract, reaction mixtures were incubated under anaerobic conditions. An arsenosugar extracted from ribbon kelp, 3-[5'-deoxy-5-(dimethylarsinoyl)-beta-ribofuranosyloxy]-2-hydroxypropanesulfonic acid, As392, was added to reaction mixtures that contained either cecal microflora or cecal tissue homogenate. These reaction mixtures were incubated at 0 or 37 degrees C for up to 48 hours to monitor biotransformation of the arsenosugar. Analysis of the reaction mixtures by IC-ICP-MS and LC-ESI-MS/MS indicated that the arsenosugar was converted primarily (95%) to its sulfur analog in less than 1 h at 37 degrees C. Conversion of As392 to its sulfur analog was much slower at 0 degrees C (21% conversion after 48 h). In reaction mixtures with cecal tissue homogenate, conversion of As392 to its sulfur analog was slower (77% conversion after 48 h at 37 degrees C). A good mass balance was found in all reaction mixtures between the amount of arsenosugar added and the sum of all detected arsenic-containing products. LC-ESI-MS/MS spectra of the sulfur-containing arsenosugar formed in all reaction mixtures containing cecal microflora compared well with those of a synthetic standard. These results suggest that the anaerobic microflora of the gastrointestinal tract can rapidly convert ingested arsenosugars to sulfur analogs. This biotransformation may affect the subsequent absorption, metabolism, and disposition of arsenic present in arsenosugars.
本研究考察了小鼠盲肠对一种砷糖的化学和微生物转化。为模拟哺乳动物胃肠道中的低氧环境，反应混合物在厌氧条件下孵育。将从海带中提取的一种砷糖，3-[5'-脱氧-5-(二甲基胂酰基)-β-呋喃核糖氧基]-2-羟基丙烷磺酸，As392，添加到含有盲肠微生物群或盲肠组织匀浆的反应混合物中。这些反应混合物在0或37℃下孵育长达48小时，以监测砷糖的生物转化。通过离子色谱-电感耦合等离子体质谱法（IC-ICP-MS）和液相色谱-电喷雾串联质谱法（LC-ESI-MS/MS）对反应混合物进行分析表明，在37℃下，砷糖在不到1小时内主要（95%）转化为其硫类似物。在0℃时，As392向其硫类似物的转化要慢得多（48小时后转化率为21%）。在含有盲肠组织匀浆的反应混合物中，As392向其硫类似物的转化较慢（37℃下48小时后转化率为77%）。在所有反应混合物中，添加的砷糖量与所有检测到的含砷产物之和之间发现了良好的质量平衡。在所有含有盲肠微生物群的反应混合物中形成的含硫砷糖的LC-ESI-MS/MS光谱与合成标准品的光谱吻合良好。这些结果表明，胃肠道的厌氧微生物群可以迅速将摄入的砷糖转化为硫类似物。这种生物转化可能会影响砷糖中砷的后续吸收、代谢和分布。
