Sulfide are widely accumulated in aquatic environments under anaerobic conditions, which cause health problems of aquatic animals, yet their toxic effects to benthic bivalves are not well understood. We investigated the effects of sulfide on innate immunity of the blood clam Tegillarca granosa. Immunity-related indicators and hemolymph microbiota were investigated in the clams exposed to sulfide (via 10, 100 and 1000 μmol/L of Na₂S) over a 7-day period. The results showed that cellular immune responses in T. granosa were affected by exposure to high sulfide concentration (1000 μmol/L Na₂S), as indicated by total counts of hemocytes (THC), cell viability, ROS levels and phagocytic activities, suggesting that sulfide stress induces T. granosa more vulnerable to pathogen challenges. In addition, the Na₂S-induced stress also reshaped the hemolymph microbial community structure of T. granosa that some original genera decreased, such as Lactobacillus, Desulfovibrio and Akkermansia; some genera increased, such as Vibrio and Pseudoalteromonas in sulfide stress group. Sulfide exposure promoted the proliferation of opportunistic pathogen and reduced the diversity of microbial community in the hemolymph of T. granosa. In summary, sulfide stress had marked hemocytotoxicity, reduced immune-cell activity and increased bacterial infections in the blood clam.

硫化物在厌氧条件下广泛积聚在水生环境中，给水生动物带来健康问题，但其对底栖双壳贝类的毒性作用尚不清楚。我们研究了硫化物对血蛤Tegillarca granosa的先天免疫的影响。在 7 天的时间里，对暴露于硫化物（通过 10、100 和 1000 μmol/L Na _{2 S）的蛤蜊进行了免疫相关指标和血淋巴微生物群的研究。}结果表明，如血细胞总数 (THC)、细胞活力、ROS 水平和吞噬活性所示，暴露于高浓度硫化物 (1000 μmol/L Na _{2 S) 会影响}T. granosa的细胞免疫反应，这表明硫化物胁迫诱导T. granosa更容易受到病原体的挑战。此外，Na ₂ S 诱导的胁迫还重塑了原属乳酸杆菌、脱硫弧菌和阿克曼氏菌等一些原属减少的T. granosa的血淋巴微生物群落结构；硫化物胁迫组中一些属增加，如弧菌和假交替单胞菌。硫化物暴露促进了机会性病原体的增殖，降低了T. granosa血淋巴中微生物群落的多样性。总之，硫化物应激具有显着的血细胞毒性，降低了免疫细胞活性并增加了血蛤中的细菌感染。