Department of Biology, College of Charleston, Charleston, SC, 29412, USA.
Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
Parasitol Res. 2024 Sep 5;123(9):317. doi: 10.1007/s00436-024-08333-8.
The spotted seatrout, Cynoscion nebulosus, is a popular game fish in the southeastern USA. It is estimated that nearly 90% of the adult population in South Carolina estuaries are infected in their skeletal muscle by the myxosporean, Kudoa inornata. However, little is known about this parasite's biology, including the distribution and densities of myxospores within tissues of infected fish, which we expect affect the physiology of their hosts. In order to correlate densities with physiological parameters in future studies, we quantified the myxospores density in muscle and characterized the variation among individual fish. Naïve juvenile seatrout was experimentally infected via presumed K. inornata actinospores exposure to raw seawater. A plug of muscle was extracted from two bilaterally symmetrical regions in the epaxial fillet from fresh and frozen carcasses. Variation in density data was calculated both within and among individuals. Within individuals, density counts were compared between left- and right-side biopsies. There was no significant difference between fresh and frozen plugs, and variation among individuals accounted for the greatest proportion of variation at 68.8%, while variation within individuals was substantial at 25.6%. Simulation and correlation tests confirmed that bilaterally symmetrical replicates varied significantly within individuals. When sampled from areas surrounding the initial biopsies, myxospore density estimates were more similar than between sides. Our findings have important implications for sampling design, particularly for studies investigating physiological parameters at the cellular or molecular level in association with parasite infection.
斑点叉尾鮰，Cynoscion nebulosus，是美国东南部流行的游钓鱼类。据估计，南卡罗来纳州河口近 90%的成年种群在其骨骼肌中感染了粘孢子虫 Kudoa inornata。然而，对于这种寄生虫的生物学特性，包括感染鱼组织内的粘孢子囊的分布和密度，我们知之甚少，我们预计这些特性会影响宿主的生理学特性。为了在未来的研究中将密度与生理参数相关联，我们量化了肌肉中的粘孢子囊密度，并描述了感染鱼个体之间的变化。通过将幼稚的斑点叉尾鮰暴露在含有粘孢子囊的生海水中来进行实验感染。从新鲜和冷冻的鱼尸中，从背鳍鱼片的两个双侧对称区域提取肌肉塞。在个体内和个体间计算密度数据的变化。在个体内，比较了左右侧活检的密度计数。新鲜和冷冻塞之间没有显著差异，个体间的变异占总变异的最大比例为 68.8%，而个体内的变异则相当大，占 25.6%。模拟和相关性测试证实，双侧对称重复个体内差异显著。当从初始活检周围区域取样时，粘孢子囊密度估计值比两侧之间的更相似。我们的研究结果对采样设计具有重要意义，特别是对于研究与寄生虫感染相关的细胞或分子水平的生理参数的研究。
