Tanaka-Kumazawa Kimiko, Kikuchi Yuichiro, Sano-Kokubun Yumiko, Shintani Seikou, Yakushiji Masashi, Kuramitsu Howard K, Ishihara Kazuyuki
Department of Pediatric Dentistry, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
Department of Microbiology, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo, 101-0061, Japan.
BMC Oral Health. 2016 Jul 16;17(1):18. doi: 10.1186/s12903-016-0243-7.
Treponema denticola is strongly associated with the development of periodontal disease. Both synergistic and antagonistic effects are observed among bacterial species in the process of biofilm formation. Bacteriocin-related genes have not yet been fully characterized in periodontopathic bacteria. The aim of this study was to detect and characterize bacteriocin-associated proteins in T. denticola.
The whole genome sequence of T. denticola ATCC 35405 was screened with a Streptococcus mutans bacteriocin immunity protein (ImmA/Bip) sequence. The prevalence of homologous genes in T. denticola strains was then investigated by Southern blotting. Expression of the genes was evaluated by qRT-PCR.
In the genome sequence of T. denticola, an amino acid sequence coded by the open reading frame TDE_0719 showed 26 % identity with the S. mutans ImmA. Furthermore, two protein sequences encoded by TDE_0425 and TDE_2431 in T. denticola ATCC 35405 showed ~40 % identity with that coded by TDE_0719. Therefore, TDE_0425, TDE_0719, and TDE_2431 were designated as tepA1, A2, and A3, respectively. Open reading frames showing similarity to the HlyD family of secretion proteins were detected downstream of tepA1, A2, and A3. They were designated as tepB1, B2, and B3, respectively. A gene harboring a bacteriocin-like signal sequence was detected upstream of tepA1. The prevalence of tepA1 and A2 differed among Treponema species. Susceptibility to chloramphenicol and ofloxacin was slightly decreased in a tepA2 mutant while that to kanamycin was increased. Expression of tepA3-B3 was increased in the tepA2 mutant.
These results indicate that T. denticola ATCC 35405 has three potential bacteriocin export proteins and that the presence of these genes differs among the Treponema strains. TepA3-B3 of the corresponding proteins may be involved in resistance to chloramphenicol.
具核梭杆菌与牙周病的发展密切相关。在生物膜形成过程中，细菌种类之间观察到协同和拮抗作用。牙周病原菌中与细菌素相关的基因尚未得到充分表征。本研究的目的是检测和表征具核梭杆菌中与细菌素相关的蛋白质。
用变形链球菌细菌素免疫蛋白（ImmA/Bip）序列筛选具核梭杆菌ATCC 35405的全基因组序列。然后通过Southern印迹法研究具核梭杆菌菌株中同源基因的流行情况。通过qRT-PCR评估基因的表达。
在具核梭杆菌的基因组序列中，由开放阅读框TDE_0719编码的氨基酸序列与变形链球菌ImmA具有26%的同一性。此外，具核梭杆菌ATCC 35405中由TDE_0425和TDE_2431编码的两个蛋白质序列与由TDE_0719编码的序列具有约40%的同一性。因此，TDE_0425、TDE_0719和TDE_2431分别被命名为tepA1、A2和A3。在tepA1、A2和A3的下游检测到与分泌蛋白HlyD家族相似的开放阅读框。它们分别被命名为tepB1、B2和B3。在tepA1上游检测到一个含有类细菌素信号序列的基因。tepA1和A2的流行率在不同的密螺旋体物种中有所不同。tepA2突变体对氯霉素和氧氟沙星的敏感性略有降低，而对卡那霉素的敏感性增加。tepA3-B3在tepA2突变体中的表达增加。
这些结果表明，具核梭杆菌ATCC 35405具有三种潜在的细菌素输出蛋白，并且这些基因的存在在不同的密螺旋体菌株中有所不同。相应蛋白质的TepA3-B3可能参与对氯霉素的抗性。
