Abstract：
Microplastics pollution threatens to marine organisms, particularly bivalves that actively ingest and accumulate microplastics of certain sizes, potentially disrupting intestinal homeostasis. This study investigated the microplastic abundance in wild and farmed mussels around Singapore, and examined the size-dependent effects of nano- to micro-scale polystyrene (0.5 µm/5 µm/50 µm) on the mussel intestinal microbiome in the laboratory. The field investigation revealed higher microplastic abundance in farmed mussels compared to wild ones. Experimentally, mussels exposed to 0.6 mg/L of microplastics for 7 days, followed by a 7-day depuration period, showed substantial impacts on Spirochaetes and Proteobacteria, facilitating the proliferation of pathogenic species and differentially affecting their pathogenic contributions. Metagenomics analysis revealed that microplastic exposure reduced Spirochaeta\'s contribution to virulence and pathogenicity loss, did not affect Vibrio and Oceanispirochaeta\'s pathogenicity, and increased Treponema and Oceanispirochaeta\'s contributions to pathogenicity loss. Moreover, microplastics increased transmembrane transporters and impacted oxidative phosphorylation enzymes, impairing energy metabolism. These effects persisted after depuration, indicating lack of resilience in the microbiome. Nano- and micro-scale plastics perturbed the mussel microbiome composition and functions in a size-dependent manner, with nano-plastics being the most disruptive. The increasing use and sale of aquaculture equipment of plastic may exacerbate the intestinal dysbiosis in bivalves, which threatens consumers\' health.
摘要：
微塑料污染威胁海洋生物，特别是积极摄取和积累一定尺寸的微塑料的双壳类动物，可能会破坏肠道稳态。这项研究调查了新加坡周围野生和养殖贻贝中的微塑料丰度，并在实验室中检查了纳米到微米级聚苯乙烯（0.5µm/5µm/50µm）对贻贝肠道微生物组的尺寸依赖性影响。实地调查显示，与野生贻贝相比，养殖贻贝中的微塑料丰度更高。实验上,贻贝暴露于0.6mg/L的微塑料中7天，接下来是7天的净化期，对螺旋藻和变形杆菌有重大影响，促进致病物种的增殖，并差异地影响其致病贡献。宏基因组学分析显示，微塑料暴露降低了Spirochaeta对毒力和致病性损失的贡献，不影响弧菌和Oceanispirochaeta的致病性，并增加密螺旋体和大洋螺旋体对致病性丧失的贡献。此外，微塑料增加跨膜转运蛋白并影响氧化磷酸化酶，损害能量代谢。净化后这些影响仍然存在，表明微生物组缺乏弹性。纳米和微米级塑料扰乱了贻贝微生物组的组成，并以大小依赖的方式发挥作用，纳米塑料是最具破坏性的。越来越多的塑料水产养殖设备的使用和销售可能会加剧双壳类动物的肠道生态失调，这威胁到消费者的健康。
