Institute for Medical Microbiology and Virology, University Medical Center Göttingen, 37075, Göttingen, Germany.
Department of Medical Microbiology, Maseno University Medical School, Private Bag, Maseno, 40105, Kenya.
BMC Microbiol. 2024 May 31;24(1):191. doi: 10.1186/s12866-024-03348-8.
The main natural reservoir for Campylobacter jejuni is the avian intestinal tract. There, C. jejuni multiplies optimally at 42 °C - the avian body temperature. After infecting humans through oral intake, the bacterium encounters the lower temperature of 37 °C in the human intestinal tract. Proteome profiling by label-free mass spectrometry (DIA-MS) was performed to examine the processes which enable C. jejuni 81-176 to thrive at 37 °C in comparison to 42 °C. In total, four states were compared with each other: incubation for 12 h at 37 °C, for 24 h at 37 °C, for 12 h at 42 °C and 24 h at 42 °C.
It was shown that the proteomic changes not only according to the different incubation temperature but also to the length of the incubation period were evident when comparing 37 °C and 42 °C as well as 12 h and 24 h of incubation. Altogether, the expression of 957 proteins was quantifiable. 37.1 - 47.3% of the proteins analyzed showed significant differential regulation, with at least a 1.5-fold change in either direction (i.e. log FC ≥ 0.585 or log FC ≤ -0.585) and an FDR-adjusted p-value of less than 0.05. The significantly differentially expressed proteins could be arranged in 4 different clusters and 16 functional categories.
The C. jejuni proteome at 42 °C is better adapted to high replication rates than that at 37 °C, which was in particular indicated by the up-regulation of proteins belonging to the functional categories "replication" (e.g. Obg, ParABS, and NapL), "DNA synthesis and repair factors" (e.g. DNA-polymerase III, DnaB, and DnaE), "lipid and carbohydrate biosynthesis" (e.g. capsular biosynthesis sugar kinase, PrsA, AccA, and AccP) and "vitamin synthesis, metabolism, cofactor biosynthesis" (e.g. MobB, BioA, and ThiE). The relative up-regulation of proteins with chaperone function (GroL, DnaK, ClpB, HslU, GroS, DnaJ, DnaJ-1, and NapD) at 37 °C in comparison to 42 °C after 12 h incubation indicates a temporary lower-temperature proteomic response. Additionally the up-regulation of factors for DNA uptake (ComEA and RecA) at 37 °C compared to 42 °C indicate a higher competence for the acquisition of extraneous DNA at human body temperature.
空肠弯曲菌的主要天然宿主是禽类的肠道。在那里，空肠弯曲菌在 42°C 的最佳温度下繁殖 - 这是禽类的体温。通过口服感染人类后，细菌在人类肠道中遇到 37°C 的较低温度。通过无标记质谱（DIA-MS）进行蛋白质组分析，以检查使 C. jejuni 81-176 在 37°C 下茁壮成长的过程，与 42°C 相比。总共将四个状态相互比较：在 37°C 孵育 12 小时，在 37°C 孵育 24 小时，在 42°C 孵育 12 小时，在 42°C 孵育 24 小时。
结果表明，当比较 37°C 和 42°C 以及孵育 12 小时和 24 小时时，不仅根据不同的孵育温度，而且根据孵育时间的长短，蛋白质组的变化都很明显。总共可定量表达 957 种蛋白质。分析的蛋白质中有 37.1%至 47.3%表现出明显的差异调节，至少有 1.5 倍的变化方向（即 log FC≥0.585 或 log FC≤-0.585），并且 FDR 调整后的 p 值小于 0.05。差异表达的蛋白质可以排列成 4 个不同的簇和 16 个功能类别。
与 37°C 相比，42°C 时的 C. jejuni 蛋白质组更适合高复制率，这尤其表明属于“复制”功能类别的蛋白质上调（例如 Obg、ParABS 和 NapL），“DNA 合成和修复因子”（例如 DNA 聚合酶 III、DnaB 和 DnaE），“脂质和碳水化合物生物合成”（例如荚膜生物合成糖激酶、PrsA、AccA 和 AccP）和“维生素合成、代谢、辅助因子生物合成”（例如 MobB、BioA 和 ThiE）。与 42°C 相比，在 12 小时孵育后，37°C 时具有伴侣功能的蛋白质（GroL、DnaK、ClpB、HslU、GroS、DnaJ、DnaJ-1 和 NapD）的相对上调表明暂时的低温蛋白质组反应。此外，与 42°C 相比，37°C 时 DNA 摄取因子（ComEA 和 RecA）的上调表明在人体温度下获取外源 DNA 的能力更高。
