University of Bologna, Department of Biological, Geological, and Environmental Sciences, P.zza di P.ta S. Donato 1, 40100 Bologna, Italy; University of Bologna, Inter-Departmental Research Centre for Environmental Science (CIRSA), Via S. Alberto 163, 48123 Ravenna, Italy.
University of Bologna, Department of Biological, Geological, and Environmental Sciences, P.zza di P.ta S. Donato 1, 40100 Bologna, Italy; University of Bologna, Inter-Departmental Research Centre for Environmental Science (CIRSA), Via S. Alberto 163, 48123 Ravenna, Italy.
Environ Pollut. 2018 Oct;241:1038-1047. doi: 10.1016/j.envpol.2018.06.035. Epub 2018 Jun 14.
The widespread occurrence of microplastics (MP) in the marine environment is cause of increasing concerns about the safety of the exposed ecosystems. Although the effects associated to the MP uptake have been studied in most marine taxa, the knowledge about their sub-lethal impacts on early life stages of marine species is still limited. Here, we investigated the uptake/retention of 3-μm polystyrene MP by early stages of the Mediterranean mussel Mytilus galloprovincialis, and the related effects on gut clearance, feeding efficiency, morphological and transcriptional parameters involved in embryo-larval development. Uptake measurements were performed on larvae at 48 h, 3, 6 and 9 days post fertilization (pf) after exposure to a range of 50-10,000 particles mL. At all tested pf periods, treatments resulted in a significant and linear increase of MP uptake with increasing concentrations, though levels measured at 48 h pf were significantly lower compared to 3-9 d pf. Ingested MP were retained up to 192 h in larvae's gut, suggesting a physical impact on digestive functions. No change was noted between the consumption of microalgae Nannochloropsis oculata by larvae when administered alone or in the presence of an identical concentration (2000 items mL) of MP. The exposure to 50-10,000 MP mL did not alter the morphological development of mussel embryos; however, transcriptional alterations were observed at 50 and 500 MP mL, including the up-regulation of genes involved in shell biogenesis (extrapallial protein; carbonic anhydrase; chitin synthase) and immunomodulation (myticin C; mytilin B), and the inhibition of those coding for lysosomal enzymes (hexosaminidase; β-glucorinidase; catepsin-L). In conclusion, though not highlighting morphological or feeding abnormalities, data from this study revealed the onset of physical and transcriptional impairments induced by MP in mussel larvae, indicating sub-lethal impacts which could increase their vulnerability toward further environmental stressors.
微塑料（MP）在海洋环境中的广泛存在引起了人们对暴露生态系统安全性的日益关注。虽然已经研究了大多数海洋分类群中与 MP 摄取相关的影响，但对海洋物种早期生命阶段的亚致死影响的了解仍然有限。在这里，我们研究了 3-μm 聚苯乙烯 MP 在欧洲贻贝 Mytilus galloprovincialis 早期阶段的摄取/保留情况，以及对肠道清除率、摄食效率、胚胎-幼虫发育过程中涉及的形态和转录参数的相关影响。在暴露于 50-10000 个颗粒/mL 的范围内后，在受精后 48 小时、3、6 和 9 天（pf）对幼虫进行摄取测量。在所有测试的 pf 期间，处理导致 MP 摄取量随浓度的增加而显著线性增加，尽管在 48 小时 pf 测量的水平明显低于 3-9 天 pf。在幼虫的肠道中，摄入的 MP 保留时间长达 192 小时，这表明它们对消化功能有物理影响。当单独给予或在相同浓度（2000 个颗粒/mL）的 MP 存在下给予时，幼虫对微藻 Nannochloropsis oculata 的消耗没有变化。暴露于 50-10000 个 MP/mL 不会改变贻贝胚胎的形态发育；然而，在 50 和 500 个 MP/mL 时观察到转录变化，包括参与壳生物发生的基因（外套蛋白；碳酸酐酶；几丁质合酶）和免疫调节（肌肽 C；肌肽 B）的上调，以及编码溶酶体酶（己糖胺酶；β-葡糖苷酸酶；组织蛋白酶-L）的基因的抑制。总之，尽管本研究没有突出形态或摄食异常，但数据显示了 MP 在贻贝幼虫中引起的物理和转录损伤的发生，表明亚致死影响可能会增加它们对进一步环境胁迫的脆弱性。
