Coexistence of organisms and pathogens has resulted in the evolution of efficient antimicrobial defense, especially at the embryonic stage. This investigation aimed to substantiate the hypothesis that the layers of silk in a spider cocoon play a role in the immunity of the embryos against microorganisms present in the external environment. A two-step interdisciplinary attempt has been made. First, the eggs and empty cocoons of the spider Parasteatoda tepidariorum were incubated on lysogeny broth agar media for 3 d. In the samples of eggs, no growth of bacteria was detected. This indicated that the eggs inside cocoons were sterile. Therefore, in the second step, the cocoons and egg surface were analyzed using SEM, TEM, and LM. The obtained images demonstrated that both inner and outer layers of the silk are built of threads of the same diameter, set in an irregular manner, and randomly clustered into groups. The threads in the outer layer were packed more densely than in the inner one. TEM analysis revealed threads of two types of fibrils and their arrangement. The resultant thread tangle of the cocoon, possibly correlated with the ultrastructure of the fibers, seems to be an example of a structure-function relationship playing a crucial ecoimmunological role in spider embryonic development.

中文翻译：

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无菌胶囊-鸡蛋茧覆盖物构成了蜘蛛寄生天蛾胚胎的抗菌屏障。

生物体和病原体的共存导致有效抗菌防御的演变，尤其是在胚胎阶段。这项研究旨在证实以下假设：蜘蛛茧中的丝层在胚胎对外部环境中存在的微生物的免疫力中起作用。进行了两步跨学科尝试。首先，将蜘蛛天蛾寄生虫的卵和空茧在溶源性肉汤琼脂培养基上孵育3天。在鸡蛋样品中，未检测到细菌的生长。这表明茧内的卵是不育的。因此，在第二步中，使用SEM，TEM和LM分析了茧和卵表面。所获得的图像表明，丝绸的内层和外层均由相同直径的线构成，以不规则的方式设置，并随机分组。外层中的线比内层中的线更密集。TEM分析揭示了两种原纤维的线及其排列。茧的最终缠结可能与纤维的超微结构有关，似乎是结构-功能关系的一个例子，在蜘蛛的胚胎发育中起着至关重要的生态免疫作用。