Bisphenol A-BPA, a widespread plastic additive, is an emerging contaminant of high concern and a potential endocrine disruptor in mammals. BPA also represents a potential threat for aquatic species, especially for larval stages. In the marine bivalve Mytilus galloprovincialis, BPA has been previously shown to affect early larval development and gene transcription. In this work, the effects of BPA (0.05-0.5-5 μM) were further investigated at different times post fertilization (24-28-32-48 hpf). BPA induced concentration-dependent alterations in deposition of the organic matrix and calcified shell at different larval stages, as shown by double calcofluor/calcein staining, resulting in altered phenotypes at 48hpf. Transcription of tTyrosinase-TYR, that plays a key role in remodelling of the shell organic matrix, and of HOX1, a member of homeobox genes involved in larval shell formation and neurogenesis, were evaluated by In Situ Hybrydization-ISH. BPA altered the spatial pattern of expression of both genes, with distinct effects depending on the concentration and developmental stage. Moreover, BPA affected the time course of mRNA levels for TYR from 24 to 48hpf. BPA impaired development of serotonin-5-HT-immunoreactive neurons at different times pf; at 48hpf, the reduction in the number of serotoninergic neurons was associated with developmental delay and downregulation of the 5-HT receptor-5-HTR. All the effects were observed from the lowest concentration tested, corresponding to detectable BPA levels in contaminated coastal waters. These data demonstrate that BPA interferes with key processes occurring during the first developmental stages of mussels, thus representing a potential threat for natural populations.

双酚A-BPA是一种广泛的塑料添加剂，是引起人们高度关注的新兴污染物，并且是哺乳动物中潜在的内分泌干扰物。BPA还对水生物种，尤其是幼体阶段构成潜在威胁。在海洋双壳类中，Mytilus galloprovincialis先前已证明BPA可影响幼虫的早期发育和基因转录。在这项工作中，在受精后的不同时间（24-28-32-48 hpf）进一步研究了BPA（0.05-0.5-5μM）的作用。BPA在不同的幼虫阶段诱导了有机基质和钙化壳沉积中浓度依赖性的变化，如钙氟荧光素/钙黄绿素双染色所示，导致表型在48hpf时发生了变化。通过原位杂交-ISH评估了在壳有机基质重塑中起关键作用的tTyrosinase-TYR的转录和参与幼虫壳形成和神经发生的同源盒基因成员HOX1的转录。BPA改变了这两个基因表达的空间模式，根据浓度和发育阶段的不同，其作用不同。此外，BPA影响TYR的mRNA水平随时间变化的幅度为24至48hpf。BPA在不同时间pf都会削弱5-羟色胺5 -HT免疫反应性神经元的发育；在48hpf时，5-羟色胺能神经元数量的减少与5-HT受体-5-HTR的发育延迟和下调有关。从最低测试浓度观察到所有影响，这与在受污染的沿海水域中可检测到的BPA水平相对应。这些数据表明，双酚A会干扰贻贝发育初期的关键过程，因此对自然种群构成潜在威胁。5-羟色胺能神经元数量的减少与5-HT受体-5-HTR的发育延迟和下调有关。从最低测试浓度观察到所有影响，这与在受污染的沿海水域中可检测到的BPA水平相对应。这些数据表明，双酚A会干扰贻贝发育的最初阶段发生的关键过程，因此对自然种群构成潜在威胁。5-羟色胺能神经元数量的减少与5-HT受体-5-HTR的发育延迟和下调有关。从最低测试浓度观察到所有影响，这与在受污染的沿海水域中可检测到的BPA水平相对应。这些数据表明，双酚A会干扰贻贝发育的最初阶段发生的关键过程，因此对自然种群构成潜在威胁。