Identification and characterization of a haem biosynthesis locus in Veillonella.
Identification and characterization of a haem biosynthesis locus in Veillonella.
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韦荣球菌中血红素生物合成位点的鉴定和表征。
DOI：
10.1099/mic.0.000366
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Qi,Fengxia
中科院分区：
文献类型：
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作者：
Zhou,Peng;Li,Xiaoli;Qi,Fengxia
血红素/血红素是牙龈卟啉单胞菌等牙周病病原体体外生长所必需的营养物质之一。在口腔中，这种营养物质被认为是由龈沟液提供的，龈沟液是牙龈发炎时产生的一种类似血清的渗出物。然而,P。牙龈炎也存在于没有炎症的健康牙齿生物膜中。本研究旨在回答以下问题：健康牙齿生物膜中的哪些生物为牙周病原体提供血红素/血红素？我们在这里报道了一组在牙生物膜发育中的桥接物种，具有完整的血红素生物合成基因簇。从细胞裂解液中检测到血红素的产生，表明血红素生物合成途径在微孔菌中起作用。利用唯一可转化的非典型性细孔菌（veillonella atypicaOK5），我们灭活了血红素生物合成途径中的特定关键基因。血红素（编码尿卟啉原脱羧酶）的失活不仅使血红素的产生消失，而且显著降低了ok5支持的p的生长。gingivalis。血红蛋白操纵子的荧光素酶报告基因显示p上调操纵子的表达。gingivalis。通过对HOMD数据库中所有口腔细菌基因组测序分析，发现3个属（Veillonella,PropionibacteriumandAggregatibacter）具有完整的血红素生物合成基因簇，提示它们都可能是口腔生物膜中潜在的血红素/血红素提供者。
Haemin/haem is one of the essential nutrients required by periodontopathogens such asPorphyromonas gingivalisto growin vitro. In the oral cavity, this nutrient is believed to be provided by the crevicular fluid, a serum-like exudate produced during gum inflammation. However,P. gingivalisis also present in the healthy dental biofilm where inflammation is absent. This study was designed to answer the question: what organism(s) in the healthy dental biofilm provides haemin/haem to those periodontal pathogens? We report here that veillonellae, a group of bridging species in dental biofilm development, harbour a complete gene cluster for haem biosynthesis. Haemin production was detected from cell lysate, suggesting that the haem biosynthesis pathway is functional in veillonellae. Using the only transformable strainVeillonella atypicaOK5, we inactivated specific key genes in the haem biosynthesis pathway. Inactivation ofhemE, encoding the enzyme uroporphyrinogen decarboxylase, not only abolished haemin production but also significantly decreased OK5-supported growth ofP. gingivalis. A luciferase gene reporter to thehemEHGoperon demonstrated up-regulation of operon expression byP. gingivalis. Analysis of all sequenced genomes of oral bacteria in the HOMD database identified three genera (Veillonella,PropionibacteriumandAggregatibacter) that have a complete haem biosynthesis gene cluster, suggesting that they all could be potential haemin/haem providers in the dental biofilm.