Departamento de Biologia Marinha, Universidade Federal Fluminense (UFF), Instituto de Biologia, Universidade Federal Fluminense, R. Mario Santos Braga, s/n, Niterói, CEP 24.020-141, RJ, Brazil; Departamento de Ciências do Ambiente, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Av. Pasteur, 458, CEP 22290-240, Rio de Janeiro, RJ, Brazil.
Departamento de Ecologia e Recursos Marinhos, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), Av. Pasteur, 458, CEP 22290-240, Rio de Janeiro, RJ, Brazil.
Fish Shellfish Immunol. 2018 Sep;80:115-123. doi: 10.1016/j.fsi.2018.05.061. Epub 2018 Jun 1.
The mussel Perna perna is an intertidal bivalve that is widely distributed, cultivated and consumed in South Africa, Brazil and Venezuela. Among marine resources, bivalve mollusks are one of the most impacted by anthropogenic pollution, as they can accumulate pathogenic bacteria and water pollutants. Hemocytes are molluscan defense cells, and their abundance and functions can be affected in response to contaminants, such as bacterial load. However, no previous study has investigated the immune response of P. perna hemocytes. The aim of this study was to evaluate several immune parameters in P. perna as indicators of fecal pollution in mussel hemolymph and in seawater. We collected mussels and adjacent seawater from beaches with different levels of fecal contamination in Rio de Janeiro state (Brazil): Vermelha Beach (VB); Icaraí Beach (IB); Urca Beach (UB); and Jurujuba Beach (JB). Hemocyte parameters (density, morphology, phagocytic activity and production of Reactive Oxygen Species - ROS) were evaluated using flow cytometry. We quantified Fecal Indicator Bacteria (FIB) in seawater by the multiple tubes technique for each beach and for hemolymph by the spread-plate technique. In agreement with historical evaluation of fecal contamination levels, UB presented the highest FIB abundance in seawater (thermotolerant coliforms, TEC = 1600 NMP 100 mL), whereas VB exhibited the lowest (TEC = 17 NMP 100 mL). UB mussels had six and eight times higher hemocyte density and phagocytic activity, respectively, than mussels from VB. Mussels from VB and IB presented a significantly lower number of total coliforms in hemolymph and a significantly higher relative internal complexity of hemocytes than those from UB and JB (p ≤ 0.01, PERMANOVA). ROS production by hemocytes was significantly lower in mussels from VB compared to those from JB (p = 0.04, ANOVA). Our results indicate a significant relationship between the level of fecal contamination in aquatic environments and the immune response of mussel hemocytes. Immune-related parameters may therefore be useful as indicators of bivalve health and environmental quality. Our flow cytometric analysis of P. perna hemocytes represents a new approach for studying Perna perna biology and might represent a novel tool for measuring organic pollution and water quality.
贻贝是一种广泛分布于南非、巴西和委内瑞拉的潮间带双壳贝类，被广泛养殖和食用。在海洋资源中，双壳贝类是受人为污染影响最严重的物种之一，因为它们可以积累致病细菌和水污染物。血细胞是软体动物的防御细胞，其数量和功能会因污染物（如细菌负荷）而发生变化。然而，以前没有研究调查过贻贝血细胞的免疫反应。本研究的目的是评估几种贻贝血细胞的免疫参数，作为贻贝血淋巴和海水中粪便污染的指标。我们从里约热内卢州（巴西）不同粪便污染程度的海滩采集贻贝和相邻海水：红海滩（VB）；伊卡拉伊海滩（IB）；乌尔卡海滩（UB）；和茹鲁贾巴海滩（JB）。使用流式细胞术评估血细胞参数（密度、形态、吞噬活性和活性氧物质（ROS）的产生）。我们使用多管技术对每个海滩的海水中的粪便指示细菌（FIB）进行了量化，并用平板扩散技术对血淋巴中的 FIB 进行了量化。与粪便污染水平的历史评估一致，UB 海水中的 FIB 丰度最高（耐热大肠菌群，TEC=1600 NMP 100 mL），而 VB 最低（TEC=17 NMP 100 mL）。与 VB 贻贝相比，UB 贻贝的血细胞密度和吞噬活性分别高出六倍和八倍。VB 和 IB 贻贝的血淋巴中总大肠菌群数量显著较低，血细胞相对内部复杂性显著较高（p≤0.01，PERMANOVA）。与 JB 贻贝相比，VB 贻贝的血细胞 ROS 产生显著较低（p=0.04，ANOVA）。我们的结果表明，水环境污染水平与贻贝血细胞的免疫反应之间存在显著关系。因此，免疫相关参数可以作为双壳类动物健康和环境质量的有用指标。我们使用流式细胞术对贻贝血细胞的分析代表了一种研究贻贝生物学的新方法，也可能成为衡量有机污染和水质的新工具。
