Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
PLoS One. 2014 Jun 25;9(6):e100349. doi: 10.1371/journal.pone.0100349. eCollection 2014.
Many virulence genes have been detected in attenuated mutants of Brucella melitensis 16 M; nevertheless, a complete report of these genes, including the main Cluster of Orthologous Groups (COG) represented as well as the taxonomical distribution among all complete bacterial and archaeal genomes, has not been analyzed. In this work a total of 160 virulence genes that have been reported in attenuated mutants in B. melitensis were included and analyzed. Additionally, we obtained 250 B. melitensis randomly selected genes as a reference group for the taxonomical comparisons. The COGs and the taxonomical distribution profile for 789 nonredundant bacterial and archaeal genomes were obtained and compared with the whole-genome COG distribution and with the 250 randomly selected genes, respectively. The main COGs associated with virulence genes corresponded to the following: intracellular trafficking, secretion and vesicular transport (U); cell motility (N); nucleotide transport and metabolism (F); transcription (K); and cell wall/membrane/envelope biogenesis (M). In addition, we found that virulence genes presented a higher proportion of orthologs in the Euryarchaeota and Proteobacteria phyla, with a significant decrease in Chlamydiae, Bacteroidetes, Tenericutes, Firmicutes and Thermotogae. In conclusion, we found that genes related to specific functions are more relevant to B. melitensis virulence, with the COG U the most significant. Additionally, the taxonomical distribution of virulence genes highlights the importance of these genes in the related Proteobacteria, being less relevant in distant groups of organisms with the exception of Euryarchaeota.
许多毒力基因已在减毒突变体中检测到布鲁氏菌 16 M；然而，这些基因的完整报告，包括主要的同源簇（COG）的表示以及在所有完整细菌和古菌基因组中的分类分布，尚未进行分析。在这项工作中，总共包括了 160 个在减毒突变体中报道的毒力基因，并进行了分析。此外，我们获得了 250 个随机选择的布鲁氏菌基因作为分类比较的参考组。获得了非冗余细菌和古菌基因组的 COGs 和分类分布谱，并分别与全基因组 COG 分布和 250 个随机选择的基因进行了比较。与毒力基因相关的主要 COG 包括：细胞内运输、分泌和囊泡运输（U）；细胞运动（N）；核苷酸运输和代谢（F）；转录（K）；细胞壁/膜/包膜生物发生（M）。此外，我们发现毒力基因在广古菌和变形菌门中有更高比例的同源基因，而在衣原体、拟杆菌门、柔膜体纲、厚壁菌门和热球菌门中的比例显著下降。总之，我们发现与特定功能相关的基因与布鲁氏菌的毒力更为相关，COG U 最为显著。此外，毒力基因的分类分布突出了这些基因在相关变形菌中的重要性，而在与广古菌以外的其他生物体的远缘群中则不那么重要。
