Young but not defenseless: Antifungal activity during embryonic development of a social insect

      Termites live in environments heavily colonized by diverse microbial communities, including pathogens. Eggs laid within the nest likely experience similar pathogenic pressures as their older nestmates. Consequently, they may have also been under selective pressures to be immune-competent. Through in vitro experiments, we tested the ontogeny, location and strength of embryos’ antifungal activity against the fungus Metarhizium brunneum. Extraembryonic washes and intraembryonic components were incubated with fungal conidia, which was then scored for viability. Fungistatic activity was location- and stage-dependent. Extraembryonic washes had relatively weak antifungal activity. Conversely, intraembryonic contents were highly antifungal, exhibiting increased potency through development. Boiling both embryonic washes and intraembryonic contents rescued conidia viability, indicating the antifungal agent(s) is (are) heat-sensitive, and likely proteinaceous. Embryonic protein profiles shif...

白蚁栖息于被包括病原体在内的多种微生物群落高度定植的环境中。巢内产下的白蚁卵，其面临的致病压力大概率与较年长的巢友一致。因此，它们或许同样处于免疫能力相关的选择压力之下。本研究通过体外（in vitro）实验，检测了白蚁胚胎针对布鲁氏绿僵菌（Metarhizium brunneum）的抗真菌活性的发育进程、作用部位与活性强度。我们将胚胎外清洗液与胚胎内组分分别与真菌分生孢子共孵育，随后对孢子的存活率进行评分。结果显示，抗真菌活性呈现出显著的部位与发育阶段依赖性：胚胎外清洗液的抗真菌活性相对较弱；与之相反，胚胎内组分具备极强的抗真菌活性，且其效力随胚胎发育进程逐步提升。对胚胎清洗液与胚胎内组分进行煮沸处理后，孢子存活率得以恢复，这表明抗真菌物质具有热敏感性，且大概率为蛋白质类物质。胚胎蛋白质组谱随发育进程发生偏移（原文后续内容未完整呈现）。