Schulz Nora K E, Asgari Danial, Liu Siqin, Birnbaum Stephanie S L, Williams Alissa M, Prakash Arun, Tate Ann T
Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
Evolutionary Studies Initiative, Vanderbilt University, Nashville, Tennessee, USA.
Mol Ecol. 2025 Mar 20:e17726. doi: 10.1111/mec.17726.
Energetic resources within organisms fuel both parasite growth and immune responses against them, but it is unclear whether energy allocation is sufficient to explain changes in infection outcomes under the threat of multiple parasites. We manipulated diet in flour beetles (Tribolium confusum) infected with two natural parasites and used a combination of transcriptomic and phenotypic assays to investigate the role of resources in shifting metabolic and immune responses after single and co-infection. Our results suggest that relatively benign, single-celled, eukaryotic gregarine parasites alter the within-host energetic environment and, by extension, juvenile development time, in a diet-dependent manner. While they do not affect host resistance to acute bacterial infection, the mRNA-seq results reveal that they stimulate the expression of an alternative set of immune genes and promote damage to the gut, ultimately contributing to reduced survival regardless of diet. Thus, energy allocation is not sufficient to explain the immunological contribution to co-infection outcomes, emphasising the importance of mechanistic insight for predicting the impact of co-infection across levels of biological organisation.
生物体内的能量资源既为寄生虫的生长提供燃料，也为针对它们的免疫反应提供能量，但尚不清楚能量分配是否足以解释在多种寄生虫威胁下感染结果的变化。我们对感染了两种天然寄生虫的面粉甲虫（赤拟谷盗）的饮食进行了控制，并结合转录组学和表型分析，以研究资源在单一感染和共同感染后改变代谢和免疫反应中的作用。我们的结果表明，相对良性的单细胞真核球虫寄生虫以饮食依赖的方式改变宿主体内的能量环境，进而改变幼虫发育时间。虽然它们不影响宿主对急性细菌感染的抵抗力，但mRNA测序结果显示，它们会刺激另一组免疫基因的表达，并促进肠道损伤，最终导致无论饮食如何，存活率都会降低。因此，能量分配不足以解释免疫对共同感染结果的影响，这强调了机制性洞察对于预测跨生物组织水平的共同感染影响的重要性。
