Microplastics (MPs) colonized by pathogens pose significant risks to the environment and health of animals and humans, however, the strategies for pathogens colonization in MPs and the effects of its colonization on spread of pathogens have not been fully characterized. Here, we investigated the biofilm formation mechanism regulated by c-di-GMP in Hafnia paralvei Z11, and determined the effect of MPs colonized by H. paralvei Z11 on the spread of strain Z11. Overexpression of yhjH, a c-di-GMP phosphodiesterase gene, attenuated intracellular c-di-GMP level in strain Z11, leading to an increase in biofilm dispersal and a decrease in biofilm formation. Meanwhile, the decline of c-di-GMP inhibited the expression of cAMP phosphodiesterase genes, increasing the cAMP content and promoting bacterial motility, that was responsible for the increase of biofilm dispersal. Furthermore, the formation of biofilms by strain Z11 on MPs promotes its colonization, which contributes to its vertical and horizontal spread in water after colonizing polyvinyl chloride-MPs and polypropylene-MPs, respectively. Therefore, this study reveals, for the first time, MPs colonized by H. paralvei Z11 through biofilms regulated by crosstalk between c-di GMP and cAMP promote the spread of strain Z11 in water, which expands the understanding of colonization strategy of pathogens on MPs and its risk on spread of pathogens.

中文翻译：

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在 c-di-GMP 和 cAMP 的调节下，Hafnia paralvei 通过生物膜形成定植的微塑料促进了其在水中的传播


病原体定植的微塑料 （MP） 对动物和人类的环境和健康构成重大风险，然而，病原体在 MP 中的定植策略及其定植对病原体传播的影响尚未完全表征。在这里，我们研究了 c-di-GMP 在 Hafnia paralvei Z11 中调控的生物被膜形成机制，并确定了 H. paralvei Z11 定植的 MPs 对菌株 Z11 传播的影响。yhjH（一种 c-di-GMP 磷酸二酯酶基因）的过表达减弱了菌株 Z11 的细胞内 c-di-GMP 水平，导致生物膜扩散增加和生物膜形成减少。同时，c-di-GMP 的下降抑制了 cAMP 磷酸二酯酶基因的表达，增加了 cAMP 含量并促进了细菌运动，这是生物膜扩散增加的原因。此外，菌株 Z11 在 MPS 上形成生物膜促进了其定植，这有助于其在分别定植聚氯乙烯-MPs 和聚丙烯-MP 后在水中垂直和水平扩散。因此，本研究首次揭示了 H. paralvei Z11 通过受 c-di GMP 和 cAMP 之间串扰调节的生物膜定植的 MP 促进了菌株 Z11 在水中的传播，这扩大了对病原体在 MPs 上的定植策略及其对病原体传播风险的理解。