Skovran E, Downs D M
Department of Bacteriology, University of Wisconsin-Madison, 53706, USA.
J Bacteriol. 2000 Jul;182(14):3896-903. doi: 10.1128/JB.182.14.3896-3903.2000.
The metabolic consequences of two insertions, iscR1::MudJ and iscA2::MudJ, in the isc gene cluster of Salmonella enterica serovar Typhimurium were studied. Each of these insertions had polar effects and caused a nutritional requirement for the thiazole moiety of thiamine. Data showed that IscS was required for the synthesis of nicotinic acid and the thiazole moiety of thiamine and that one or more additional isc gene products were required for a distinct step in the thiazole biosynthetic pathway. Strains with isc lesions had reduced succinate dehydrogenase and aconitase activities. Furthermore, isc mutants accumulated increased levels of pyruvate in the growth medium in response to exogenously added iron (FeCl(3)), and this response required a functional ferric uptake regulator, Fur.
对肠炎沙门氏菌鼠伤寒血清型isc基因簇中两个插入片段iscR1::MudJ和iscA2::MudJ的代谢后果进行了研究。这些插入片段中的每一个都具有极性效应，并导致对硫胺素噻唑部分的营养需求。数据表明，IscS是烟酸和硫胺素噻唑部分合成所必需的，并且噻唑生物合成途径中的一个不同步骤需要一种或多种其他isc基因产物。具有isc损伤的菌株琥珀酸脱氢酶和乌头酸酶活性降低。此外，isc突变体在生长培养基中对外源添加的铁（FeCl₃）作出反应时，丙酮酸水平积累增加，并且这种反应需要功能性的铁摄取调节因子Fur。
