Hannig C, Ruggeri A, Al-Khayer B, Schmitz P, Spitzmüller B, Deimling D, Huber K, Hoth-Hannig W, Bowen W H, Hannig M
Department of Operative Dentistry and Periodontology, University of Freiburg, Hugstetter Str. 55, D-79106 Freiburg, Germany.
Arch Oral Biol. 2008 Nov;53(11):1003-10. doi: 10.1016/j.archoralbio.2008.04.005. Epub 2008 Jun 2.
Glucosyltransferases (GTFs) represent a virulence factor of mutans streptococci. The aim of the present in situ study was to investigate the distribution of different GTF-isoforms in the pellicle.
Bovine enamel slabs were fixed on buccal and palatal sites of individual splints worn by five subjects for 30 and 120 min to allow pellicle formation. Pellicle specimens were processed for transmission electron microscopy (TEM) and field emission in-lens scanning electron microscopy (FEI-SEM). Gold-immunolabelling was used for detection of GTF-isoforms B, C and D. Furthermore, glucosyltransferase activity of 3-, 30- and 120-min pellicles was tested via determination of fructose release.
All isoforms of the enzyme were found to be randomly distributed within all layers of the pellicle. In cross-sections (TEM), GTF D was the most abundant isoform. More labelled molecules were detected on buccal sites compared with palatal surfaces, the number of molecules detected increased with time. The amount of GTF B, C and D found on the pellicle surface by FEI-SEM showed no correlation with pellicle formation time or localisation in the oral cavity. Overall, GTF D was detected more frequently on the surface than GTF B and C. All pellicles tested showed GTF-activity.
The study shows for the first time the presence of the GTF-isoforms B, C and D within all layers of the in situ formed pellicle. This emphasises the impact of streptococcal products on the composition of the pellicle and illustrates a mechanism used by bacteria to colonize dental surfaces.
葡糖基转移酶（GTFs）是变形链球菌的一种毒力因子。本原位研究的目的是调查不同GTF同工型在获得性膜中的分布情况。
将牛牙釉质片固定在五名受试者佩戴的单个夹板的颊侧和腭侧部位30分钟和120分钟，以使获得性膜形成。对获得性膜标本进行透射电子显微镜（TEM）和场发射透镜内扫描电子显微镜（FEI-SEM）处理。采用金免疫标记法检测GTF同工型B、C和D。此外，通过测定果糖释放量来检测3分钟、30分钟和120分钟获得性膜的葡糖基转移酶活性。
发现该酶的所有同工型在获得性膜的所有层中随机分布。在横截面（TEM）中，GTF D是最丰富的同工型。与腭面相比，在颊侧部位检测到更多的标记分子，检测到的分子数量随时间增加。通过FEI-SEM在获得性膜表面发现的GTF B、C和D的量与获得性膜形成时间或口腔中的定位无关。总体而言，在表面检测到GTF D的频率高于GTF B和C。所有测试的获得性膜均显示出GTF活性。
该研究首次表明原位形成的获得性膜的所有层中存在GTF同工型B、C和D。这强调了链球菌产物对获得性膜组成的影响，并阐明了细菌在牙面定植所采用的一种机制。
