PDF(Pubmed)
Abstract：
BACKGROUND: Gastropods of the genus Biomphalaria (Family Planorbidae) are exploited as vectors by Schistosoma mansoni, the most common causative agent of human intestinal schistosomiasis. Using improved genomic resources, overviews of how Biomphalaria responds to S. mansoni and other metazoan parasites can provide unique insights into the reproductive, immune, and other systems of invertebrate hosts, and their responses to parasite challenges.
RESULTS: Using Illumina-based RNA-Seq, we compared the responses of iM line B. glabrata at 2, 8, and 40 days post-infection (dpi) to single infections with S. mansoni, Echinostoma paraensei (both digenetic trematodes) or Daubaylia potomaca (a nematode parasite of planorbid snails). Responses were compared to unexposed time-matched control snails. We observed: (1) each parasite provoked a distinctive response with a predominance of down-regulated snail genes at all time points following exposure to either trematode, and of up-regulated genes at 8 and especially 40dpi following nematode exposure; (2) At 2 and 8dpi with either trematode, several snail genes associated with gametogenesis (particularly spermatogenesis) were down-regulated. Regarding the phenomenon of trematode-mediated parasitic castration in molluscs, we define for the first time a complement of host genes that are targeted, as early as 2dpi when trematode larvae are still small; (3) Differential gene expression of snails with trematode infection at 40dpi, when snails were shedding cercariae, was unexpectedly modest and revealed down-regulation of genes involved in the production of egg mass proteins and peptide processing; and (4) surprisingly, D. potomaca provoked up-regulation at 40dpi of many of the reproduction-related snail genes noted to be down-regulated at 2 and 8dpi following trematode infection. Happening at a time when B. glabrata began to succumb to D. potomaca, we hypothesize this response represents an unexpected form of fecundity compensation. We also document expression patterns for other Biomphalaria gene families, including fibrinogen domain-containing proteins (FReDs), C-type lectins, G-protein coupled receptors, biomphalysins, and protease and protease inhibitors.
CONCLUSIONS: Our study is relevant in identifying several genes involved in reproduction that are targeted by parasites in the vector snail B. glabrata and that might be amenable to manipulation to minimize their ability to serve as vectors of schistosomes.
RESULTS: Using Illumina-based RNA-Seq, we compared the responses of iM line B. glabrata at 2, 8, and 40 days post-infection (dpi) to single infections with S. mansoni, Echinostoma paraensei (both digenetic trematodes) or Daubaylia potomaca (a nematode parasite of planorbid snails). Responses were compared to unexposed time-matched control snails. We observed: (1) each parasite provoked a distinctive response with a predominance of down-regulated snail genes at all time points following exposure to either trematode, and of up-regulated genes at 8 and especially 40dpi following nematode exposure; (2) At 2 and 8dpi with either trematode, several snail genes associated with gametogenesis (particularly spermatogenesis) were down-regulated. Regarding the phenomenon of trematode-mediated parasitic castration in molluscs, we define for the first time a complement of host genes that are targeted, as early as 2dpi when trematode larvae are still small; (3) Differential gene expression of snails with trematode infection at 40dpi, when snails were shedding cercariae, was unexpectedly modest and revealed down-regulation of genes involved in the production of egg mass proteins and peptide processing; and (4) surprisingly, D. potomaca provoked up-regulation at 40dpi of many of the reproduction-related snail genes noted to be down-regulated at 2 and 8dpi following trematode infection. Happening at a time when B. glabrata began to succumb to D. potomaca, we hypothesize this response represents an unexpected form of fecundity compensation. We also document expression patterns for other Biomphalaria gene families, including fibrinogen domain-containing proteins (FReDs), C-type lectins, G-protein coupled receptors, biomphalysins, and protease and protease inhibitors.
CONCLUSIONS: Our study is relevant in identifying several genes involved in reproduction that are targeted by parasites in the vector snail B. glabrata and that might be amenable to manipulation to minimize their ability to serve as vectors of schistosomes.
摘要：
背景：曼氏血吸虫利用Biomphalaria属（Planorbidae家族）的腹足类动物作为载体，人类肠道血吸虫病最常见的病原体。利用改进的基因组资源，Biomphalaria如何响应S.mansoni和其他后生寄生虫的概述可以提供对生殖的独特见解，免疫，和其他无脊椎动物宿主系统，以及他们对寄生虫挑战的反应。
结果：使用基于Illumina的RNA-Seq，我们比较了感染后2、8和40天的iM品系光滑芽孢杆菌（dpi）与曼氏链球菌的单次感染的反应，paraensei棘球虫（两种双遗传吸虫）或Daubayliapotomaca（扁平蜗牛的线虫寄生虫）。将反应与未暴露的时间匹配的对照蜗牛进行比较。我们观察到：（1）在暴露于任何一种吸虫后的所有时间点，每种寄生虫都会引起独特的反应，其中主要是下调的蜗牛基因，以及线虫暴露后8，尤其是40dpi的上调基因；（2）在2和8dpi时，一些与配子发生(特别是精子发生)相关的蜗牛基因被下调.关于软体动物吸虫介导的寄生去势现象，我们首次定义了宿主基因的互补序列，早在2dpi时吸虫幼虫还很小;(3)在40dpi时吸虫感染蜗牛的差异基因表达,当蜗牛脱落尾蚴的时候,出乎意料的是适度的，并揭示了与蛋团蛋白和肽加工产生有关的基因的下调；（4）令人惊讶的是，D.potomaca在吸虫感染后，许多与繁殖相关的蜗牛基因在40dpi引起上调，这些基因在2和8dpi被下调。发生在B.glabrata开始屈服于D.potomaca的时候，我们假设这种反应代表了一种意想不到的繁殖力补偿形式。我们还记录了其他Biomphalaria基因家族的表达模式，包括含纤维蛋白原结构域的蛋白质（FReDs），C型凝集素,G蛋白偶联受体，生物溶蛋白酶,以及蛋白酶和蛋白酶抑制剂。
结论：我们的研究与鉴定几个与繁殖有关的基因有关，这些基因被载体蜗牛B.glabrata中的寄生虫所靶向，并且可能适合于操作以最小化其作为载体的能力。血吸虫。
结果：使用基于Illumina的RNA-Seq，我们比较了感染后2、8和40天的iM品系光滑芽孢杆菌（dpi）与曼氏链球菌的单次感染的反应，paraensei棘球虫（两种双遗传吸虫）或Daubayliapotomaca（扁平蜗牛的线虫寄生虫）。将反应与未暴露的时间匹配的对照蜗牛进行比较。我们观察到：（1）在暴露于任何一种吸虫后的所有时间点，每种寄生虫都会引起独特的反应，其中主要是下调的蜗牛基因，以及线虫暴露后8，尤其是40dpi的上调基因；（2）在2和8dpi时，一些与配子发生(特别是精子发生)相关的蜗牛基因被下调.关于软体动物吸虫介导的寄生去势现象，我们首次定义了宿主基因的互补序列，早在2dpi时吸虫幼虫还很小;(3)在40dpi时吸虫感染蜗牛的差异基因表达,当蜗牛脱落尾蚴的时候,出乎意料的是适度的，并揭示了与蛋团蛋白和肽加工产生有关的基因的下调；（4）令人惊讶的是，D.potomaca在吸虫感染后，许多与繁殖相关的蜗牛基因在40dpi引起上调，这些基因在2和8dpi被下调。发生在B.glabrata开始屈服于D.potomaca的时候，我们假设这种反应代表了一种意想不到的繁殖力补偿形式。我们还记录了其他Biomphalaria基因家族的表达模式，包括含纤维蛋白原结构域的蛋白质（FReDs），C型凝集素,G蛋白偶联受体，生物溶蛋白酶,以及蛋白酶和蛋白酶抑制剂。
结论：我们的研究与鉴定几个与繁殖有关的基因有关，这些基因被载体蜗牛B.glabrata中的寄生虫所靶向，并且可能适合于操作以最小化其作为载体的能力。血吸虫。
