Queiroga Fernando Ramos, Marques-Santos Luis Fernando, Hégaret Hélène, Sassi Roberto, Farias Natanael Dantas, Santana Lucas Nunes, da Silva Patricia Mirella
Laboratório de Imunologia e Patologia de Invertebrados (LABIPI), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba, Brazil.
Laboratório de Biologia Celular e do Desenvolvimento (LABID), Departamento de Biologia Molecular, Universidade Federal da Paraíba, 58051-900, João Pessoa, Paraíba, Brazil.
Aquat Toxicol. 2017 Jun;187:100-107. doi: 10.1016/j.aquatox.2017.03.019. Epub 2017 Mar 27.
Perkinsosis is a disease caused by protozoan parasites from the Perkinsus genus. In Brazil, two species, P. beihaiensis and P. marinus, are frequently found infecting native oysters (Crassostrea gasar and C. rhizophorae) from cultured and wild populations in several states of the Northeast region. The impacts of this disease in bivalves from Brazil, as well as the interactions with environmental factors, are poorly studied. In the present work, we evaluated the in vitro effects of the cyanobacteria Synechocystis spp. on trophozoites of P. marinus and haemocytes of C. gasar. Four cyanobacteria strains isolated from the Northeast Brazilian coast were used as whole cultures (WCs) and extracellular products (ECPs). Trophozoites of P. marinus were exposed for short (4h) and long (48h and 7days, the latter only for ECPs) periods, while haemocytes were exposed for a short period (4h). Cellular and immune parameters, i.e. cell viability, cell count, reactive oxygen species production (ROS) and phagocytosis of inert (latex beads) and biological particles (zymosan and trophozoites of P. marinus) were measured by flow cytometry. The viability of P. marinus trophozoites was improved in response to WCs of Synechocystis spp., which could be a beneficial effect of the cyanobacteria providing nutrients and reducing reactive oxygen species. Long-term exposure of trophozoites to ECPs of cyanobacteria did not modify in vitro cell proliferation nor viability. In contrast, C. gasar haemocytes showed a reduction in cell viability when exposed to WCs, but not to ECPs. However, ROS production was not altered. Haemocyte ability to engulf latex particles was reduced when exposed mainly to ECPs of cyanobacteria; while neither the WCs nor the ECPs modified phagocytosis of the biological particles, zymosan and P. marinus. Our results suggest a negative effect of cyanobacteria from the Synechocystis genus on host immune cells, in contrast to a more beneficial effect on the parasite cell, which could together disrupt the balance of the host-parasite interaction and make oysters more susceptible to P. marinus as well as opportunistic infections.
派金虫病是一种由派金虫属原生动物寄生虫引起的疾病。在巴西，北海派金虫和马氏派金虫这两个物种经常被发现感染东北地区几个州养殖和野生种群中的本地牡蛎（加萨巨蛎和红树巨蛎）。这种疾病对巴西双壳贝类的影响以及与环境因素的相互作用研究较少。在本研究中，我们评估了蓝藻聚球藻属对马氏派金虫滋养体和加萨巨蛎血细胞的体外影响。从巴西东北海岸分离出的四株蓝藻菌株被用作全培养物（WCs）和细胞外产物（ECPs）。马氏派金虫滋养体分别暴露于短时间（4小时）和长时间（48小时和7天，后者仅针对ECPs），而血细胞暴露于短时间（4小时）。通过流式细胞术测量细胞和免疫参数，即细胞活力、细胞计数、活性氧生成（ROS）以及对惰性（乳胶珠）和生物颗粒（酵母聚糖和马氏派金虫滋养体）的吞噬作用。马氏派金虫滋养体对聚球藻属的WCs反应时活力提高，这可能是蓝藻提供营养并减少活性氧的有益作用。滋养体长期暴露于蓝藻的ECPs对体外细胞增殖和活力没有影响。相反，加萨巨蛎血细胞暴露于WCs时细胞活力降低，但暴露于ECPs时未降低。然而，ROS生成没有改变。血细胞吞噬乳胶颗粒的能力在主要暴露于蓝藻的ECPs时降低；而WCs和ECPs均未改变对生物颗粒酵母聚糖和马氏派金虫的吞噬作用。我们的结果表明，聚球藻属蓝藻对宿主免疫细胞有负面影响，而对寄生虫细胞有更有益的影响，这可能共同破坏宿主 - 寄生虫相互作用的平衡，使牡蛎更容易受到马氏派金虫以及机会性感染。
