Chemoattraction and chemorepulsion of Strongyloides stercoralis infective larvae on a sodium chloride gradient is mediated by amphidial neuron pairs ASE and ASH, respectively
Chemoattraction and chemorepulsion of Strongyloides stercoralis infective larvae on a sodium chloride gradient is mediated by amphidial neuron pairs ASE and ASH, respectively
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DOI：
10.1016/j.vetpar.2004.01.005
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发表时间：
2004-03-25
影响因子：
2.6
通讯作者：
Schad, GA
中科院分区：
文献类型：
--
作者：
Forbes, WM;Ashton, FT;Schad, GA
根据其浓度的不同，氯化钠对粪圆线虫（Strongyloides stercoralis）的感染幼虫（L3i）有引诱剂或驱避剂的作用。在浓度梯度下，L3i被0.05 M NaCl吸引，但被2.8 M NaCl排斥。为了验证两侧神经元ASE和ASH可能分别介导吸引和排斥的假设，在激光微束照射下，将两侧神经元ASE和ASH以及控制神经元消融。当幼虫达到侵染力（L3i）后，进行NaCl梯度试验。当处于低盐度环境时，73.5%的正常对照组“向上”迁移，而26.4%的正常对照组随机爬行。相比之下，只有20.6%的ase消融L3i沿着梯度“向上”迁移，而79.4%的L3i是随机迁移的。消融控制ask消融的L3i（58.8%）沿梯度“向上”迁移，而41.1%随机爬行。当放置在高盐度区域时，100%的正常对照L3i“向下”迁移，而62.5%的ash消融L3i随机迁移，其余37.5%“向下”迁移。与ash烧蚀L3i形成鲜明对比的是，94.1%的烧蚀控制幼虫（即ask烧蚀L3i）沿梯度“向下”迁移。ASE和ash消融的L3i的迁移行为与ask消融的L3i和正常对照有显著差异（P < 0.001）。值得注意的是，87.5%的ase消融L3i未能表现出化学吸引行为，在高盐度下被积极的化学排斥。此外，70.0%的ash消融L3i未能从高盐度中被化学排斥，能够产生化学吸引行为，这表明除了与目标神经元相关的行为反应外，蠕虫保留了它们的行为反应。(C) 2004 Elsevier B.V.版权所有
Depending on its concentration, sodium chloride acts as either an attractant or a repellant to the infective larvae (L3i) of Strongyloides stercoralis. On a concentration gradient, L3i are attracted to 0.05 M NaCl, but repelled by 2.8 M. To test the hypothesis that amphidial neurons ASE and ASH might mediate attraction and repulsion, respectively, these neurons, and control neurons as well, were ablated in hatchling larvae with a laser microbeam. After the larvae attained infectivity (L3i), they were tested on a NaCl gradient. When placed at low salinity, 73.5% of normal controls migrated "up" the gradient, while 26.4% crawled randomly. In contrast, only 20.6% of ASE-ablated L3i migrated "up" the gradient, while 79.4% migrated randomly. Ablation-control ASK-ablated L3i (58.8%) migrated "up" the gradient while 41.1% crawled randomly. When placed at a region of high salinity, 100% of normal control L3i migrated "down" the gradient, whereas 62.5% of ASH-ablated L3i migrated randomly, the remaining 37.5% migrating "down" the gradient. In sharp contrast with ASH-ablated L3i, 94.1% of ablation-control larvae, i.e. ASK-ablated L3i, migrated "down" the gradient. Migration behavior of ASE- and ASH-ablated L3i was significantly different (P < 0.001) from that of ASK-ablated L3i and normal controls. It is noteworthy that 87.5% of ASE-ablated L3i that failed to exhibit chemoattractive behavior were actively chemorepelled from high salinity. Also, 70.0% of ASH-ablated L3i that failed to be chemorepelled from high salinity were capable of chemoattractive behavior, indicating that the worms had retained their behavioral responses except for those associated with the targeted neurons. (C) 2004 Elsevier B.V. All rights reserved.