Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
Escola Politécnica & Escola de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2018 Oct 4;13(10):e0205228. doi: 10.1371/journal.pone.0205228. eCollection 2018.
Microorganisms developing in the liner of the spent fuel pool (SFP) and the fuel transfer channel (FTC) of a Nuclear Power Plant (NPP) can form high radiation resistant biofilms and cause corrosion. Due to difficulties and limitations to obtain large samples from SFP and FTC, cotton swabs were used to collect the biofilm from the wall of these installations. Molecular characterization was performed using massively parallel sequencing to obtain a taxonomic and functional gene classification. Also, samples from the drainage system were evaluated because microorganisms may travel over the 12-meter column of the pool water of the Brazilian Nuclear Power Plant (Angra1), which has been functioning since 1985. Regardless of the treatment of the pool water, our data reveal the unexpected presence of Fungi (Basidiomycota and Ascomycota) as the main contaminators of the SFP and FTC. Ustilaginomycetes (Basidiomycota) was the major class contributor (70%) in the SFP and FTC reflecting the little diversity in these sites; nevertheless, Proteobacteria, Actinobacteria, Firmicutes (Bacilli) were present in small proportions. Mapping total reads against six fungal reference genomes indicate that there is, in fact, a high abundance of fungal sequences in samples collected from SFP and FTC. Analysis of the ribosomal internal transcribed spacer (ITS) 1 and 2 regions and the protein found in the mitochondria of eukaryotic cells, cytochrome b (cytb) grouped our sample fungi in the clade 7 as Ustilago and Pseudozyma. In contrast, in the drainage system, Alphaproteobacteria were present in high abundances (55%). The presence of Sphingopyxis, Mesorhizobium, Erythrobacter, Sphingomonas, Novosphingobium, Sphingobium, Chelativorans, Oceanicaulis, Acidovorax, and Cyanobacteria was observed. Based on genomic annotation data, the assessment of the biological function found a higher proportion of protein-coding sequences related to respiration and protein metabolism in SFP and FTC samples. The knowledge of this biological inventory present in the system may contribute to further studies of potential microorganisms that might be useful for bioremediation of nuclear waste.
在核电厂（NPP）的乏燃料池（SFP）和燃料转移通道（FTC）的衬里中生长的微生物可以形成高辐射抗性生物膜并引起腐蚀。由于从 SFP 和 FTC 获得大样本存在困难和限制，因此使用棉签从这些设施的壁上收集生物膜。使用大规模平行测序进行分子特征描述，以获得分类和功能基因分类。此外，还评估了排水系统的样本，因为微生物可能会在巴西核电厂（安格拉 1 号）的水池 12 米水柱中移动，该核电站自 1985 年以来一直在运行。无论水池水的处理如何，我们的数据都揭示了真菌（担子菌门和子囊菌门）出乎意料地成为 SFP 和 FTC 的主要污染物。在 SFP 和 FTC 中，担子菌门（Basidiomycota）是主要的类群贡献者（70％），反映了这些地点的多样性很小；然而，变形菌门、放线菌门、厚壁菌门（芽孢杆菌）也以小比例存在。将总读取映射到六个真菌参考基因组上表明，实际上，从 SFP 和 FTC 收集的样本中存在大量的真菌序列。对核糖体内部转录间隔区（ITS）1 和 2 区域和真核细胞线粒体中的蛋白质进行分析，细胞色素 b（cytb）将我们的样本真菌分组为 Ustilago 和 Pseudozyma 的第 7 分支。相比之下，在排水系统中，α变形菌门以高丰度（55％）存在。观察到 Sphingopyxis、Mesorhizobium、Erythrobacter、Sphingomonas、Novosphingobium、Sphingobium、Chelativorans、Oceanicaulis、Acidovorax 和蓝藻的存在。根据基因组注释数据，对生物功能的评估发现，SFP 和 FTC 样本中与呼吸和蛋白质代谢相关的蛋白质编码序列的比例更高。系统中存在这种生物库存的知识可能有助于进一步研究可能对核废料生物修复有用的潜在微生物。
