Abstract：
The investigation of the microbial community change in the biofilm, growing on the walls of a containment tank of TRIGA nuclear reactor revealed a thriving community in an oligotrophic and heavy-metal-laden environment, periodically exposed to high pulses of ionizing radiation (IR). We observed a vertical IR resistance/tolerance stratification of microbial genera, with higher resistance and less diversity closer to the reactor core. One of the isolated Bacillus strains survived 15 kGy of combined gamma and proton radiation, which was surprising. It appears that there is a succession of genera that colonizes or re-colonizes new or IR-sterilized surfaces, led by Bacilli and/or Actinobacteria, upon which a photoautotrophic and diazotrophic community is established within a fortnight. The temporal progression of the biofilm community was evaluated also as a proxy for microbial response to radiological contamination events. This indicated there is a need for better dose-response models that could describe microbial response to contamination events. Overall, TRIGA nuclear reactor offers a unique insight into IR microbiology and provides useful means to study relevant microbial dose-thresholds during and after radiological contamination.
摘要：
生物膜中微生物群落变化的调查，生长在TRIGA核反应堆的安全壳壁上，在贫营养和充满重金属的环境中发现了一个繁荣的社区，定期暴露于高脉冲的电离辐射（IR）。我们观察到微生物属的垂直红外抗性/耐受性分层，更高的阻力和更少的多样性更接近反应堆核心。分离出的芽孢杆菌菌株之一在15kGy的伽马射线和质子辐射联合作用下存活，这是令人惊讶的。似乎有一系列属在新的或红外灭菌的表面上定殖或重新定殖，由芽孢杆菌和/或放线菌领导，在两周内建立了光自养和重氮营养社区。生物膜群落的时间进展也被评估为微生物对放射性污染事件的反应的代表。这表明需要更好的剂量反应模型，可以描述微生物对污染事件的反应。总的来说,TRIGA核反应堆提供了对红外微生物学的独特见解，并提供了有用的手段来研究放射性污染期间和之后的相关微生物剂量阈值。
