No evidence for schistosome parasite fitness trade-offs in the intermediate and definitive host.
No evidence for schistosome parasite fitness trade-offs in the intermediate and definitive host.
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DOI：
10.1186/s13071-023-05730-3
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发表时间：
2023-04-17
影响因子：
3.2
通讯作者：
中科院分区：
文献类型：
--
作者：
吸虫曼氏血吸虫以水生蜗牛为中间宿主，以脊椎动物为最终宿主来完成其生命周期。我们之前的研究表明，一个关键的传播特征——从受感染的Biomphalaria spp.蜗牛身上脱落的尾蚴幼虫的数量——在不同的寄生虫种群内部和之间存在显著差异，并由五个基因位点遗传控制。我们研究了一种假设，即在中间蜗牛宿主中表现出高繁殖适合度的寄生虫基因型的成功可能被最终脊椎动物宿主的低繁殖适合度所抵消。我们通过选择在蜗牛中产生高或低数量幼虫的寄生虫后代，然后比较适合度参数和啮齿动物宿主的毒力来研究这种权衡假说。我们使用从SmLE （HS亲本）和SmBRE （LS亲本）遗传杂交产生的F2后代中分离的两种曼氏血吸虫（高脱壳（HS）和低脱壳（LS）系）感染自交系BALB/c小鼠。我们用F3子代感染两个近交系光螺种群。然后，我们比较了这两种选定的寄生虫系在啮齿动物宿主中的生活史特征和毒力，以了解寄生虫感染最终宿主时决定尾蚴脱落的基因的多效性作用。无论蜗牛的遗传背景如何，HS寄生虫都会脱落大量的尾蚴，这对蜗牛的生理（通过漆酶样活性和血红蛋白率来测量）都有不利的影响。相比之下，选择的LS寄生虫较少脱落尾蚴，对蜗牛生理的影响较小。同样，HS虫比LS虫具有更高的生殖适应性，产生更多的F3 miracidia幼虫。这种传播的增加与对啮齿动物宿主的毒力增加有关，其特征是肝脾大和肝纤维化更强。结果表明，血吸虫在中间寄主和终寄主中繁殖和生殖适合度呈正相关（正多效性）。因此，我们拒绝了我们的权衡假设。我们还发现，无论中间蜗牛宿主的遗传背景如何，我们选择的血吸虫系都表现出低和高脱落表型。
The trematode parasite Schistosoma mansoni uses an aquatic snail intermediate and a vertebrate definitive host to complete its life cycle. We previously showed that a key transmission trait—the number of cercariae larvae shed from infected Biomphalaria spp. snails—varies significantly within and between different parasite populations and is genetically controlled by five loci. We investigated the hypothesis that the success of parasite genotypes showing high propagative fitness in the intermediate snail host may be offset by lower reproductive fitness in the definitive vertebrate host. We investigated this trade-off hypothesis by selecting parasite progeny producing high or low number of larvae in the snail and then comparing fitness parameters and virulence in the rodent host. We infected inbred BALB/c mice using two Schistosoma mansoni parasite lines [high shedder (HS) and low shedder (LS) lines] isolated from F2 progeny generated by genetic crosses between SmLE (HS parent) and SmBRE (LS parent) parasites. We used the F3 progeny to infect two populations of inbred Biomphalaria glabrata snails. We then compared life history traits and virulence of these two selected parasite lines in the rodent host to understand pleiotropic effects of genes determining cercarial shedding in parasites infecting the definitive host. HS parasites shed high numbers of cercariae, which had a detrimental impact on snail physiology (measured by laccase-like activity and hemoglobin rate), regardless of the snail genetic background. In contrast, selected LS parasites shed fewer cercariae and had a lower impact on snail physiology. Similarly, HS worms have a higher reproductive fitness and produced more viable F3 miracidia larvae than LS parasites. This increase in transmission is correlated with an increase in virulence toward the rodent host, characterized by stronger hepato-splenomegaly and hepatic fibrosis. These experiments revealed that schistosome parasite propagative and reproductive fitness was positively correlated in intermediate and definitive host (positive pleiotropy). Therefore, we rejected our trade-off hypothesis. We also showed that our selected schistosome lines exhibited low and high shedding phenotype regardless of the intermediate snail host genetic background.
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影响因子：
3.3
作者：
Hedrick, PW
通讯作者：
Hedrick, PW
影响因子：
1.5
作者：
Chevalier FD;Le Clec'h W;Alves de Mattos AC;LoVerde PT;Anderson TJ
通讯作者：
Anderson TJ
影响因子：
3.2
作者：
Le Clec'h W;Anderson TJ;Chevalier FD
通讯作者：
Chevalier FD
影响因子：
2.1
作者：
Brown, K. E.;Kelly, J. K.
通讯作者：
Kelly, J. K.
DOI：
10.1098/rspb.2000.1367
发表时间：
2001-02-07
影响因子：
4.7
作者：
Davies, CM;Webster, JP;Woolhouse, MEJ
通讯作者：
Woolhouse, MEJ