School of Animal Science and Technology, Shihezi University, Shihezi City, Xinjiang 832000, P.R. China.
School of Life Science, Shihezi University, Shihezi City, Xinjiang 832000, P.R. China.
Can J Microbiol. 2020 May;66(5):351-358. doi: 10.1139/cjm-2019-0393. Epub 2020 Feb 10.
Iron is a fundamental element required by most organisms, including . Several researchers have suggested that the iron response regulator () and rhizobial iron regulator () genes regulate iron acquisition by , influencing heme synthesis by and virulence of this pathogen. However, little is known about another species, . In this research, we successfully constructed two mutants: M5-90Δ and M5-90Δ. The adhesion, invasion, and intracellular survivability of these two mutants were evaluated in RAW264.7 cells infected with 1 × 10 CFU of M5-90Δ, M5-90Δ, or M5-90. We also tested the sensitivity of cells to hydrogen peroxide and their ability to grow. In addition, the virulence of these two mutants was evaluated in BALB/c mice. The results showed that the ability of these two mutants to invade and adhere inside the murine macrophages RAW264.7 was attenuated but their ability to replicate intracellularly was strengthened, enhancing the resistance to hydrogen peroxide. The M5-90Δ mutant showed stronger growth ability than the parental strain under iron-limiting conditions. No differences were observed in the number of bacteria in spleen between M5-90 and M5-90Δ at 7 or 15 days postinfection. However, the number of M5-90Δ in spleen reduced significantly at 15 days postinfection. The splenic index of the M5-90Δ group is evidently lower than that of M5-90. This is the first report that and genes of are associated not only with virulence but also with growth ability. Together, our data suggest that M5-90Δ is a promising vaccine candidate.
铁是大多数生物体必需的基本元素，包括。几位研究人员认为，铁反应调节剂（）和根瘤菌铁调节因子（）基因通过影响该病原体的血红素合成和毒力来调节对的铁摄取。然而，对于另一种物种，知之甚少。在这项研究中，我们成功构建了两个突变体：M5-90Δ和 M5-90Δ。在 RAW264.7 细胞中用 1×10 CFU 的 M5-90Δ、M5-90Δ或 M5-90 感染后，评估了这两个突变体的粘附、侵袭和细胞内存活率。我们还测试了细胞对过氧化氢的敏感性及其生长能力。此外，在 BALB/c 小鼠中评估了这两个突变体的毒力。结果表明，这两个突变体侵袭和粘附在鼠巨噬细胞 RAW264.7 内的能力减弱，但复制细胞内的能力增强，增强了对过氧化氢的抵抗力。在缺铁条件下，M5-90Δ突变体的生长能力强于亲本菌株。在感染后 7 或 15 天，M5-90 和 M5-90Δ 细菌在脾脏中的数量没有差异。然而，在感染后 15 天，M5-90Δ 脾脏中的细菌数量显著减少。M5-90Δ 组的脾指数明显低于 M5-90 组。这是首次报道与毒力有关的和基因不仅与生长能力有关。总之，我们的数据表明 M5-90Δ 是一种有前途的疫苗候选物。
