Stickleback sperm saved by salt in ovarian fluid
Stickleback sperm saved by salt in ovarian fluid
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DOI：
10.1242/jeb.02481
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发表时间：
2006-11-01
影响因子：
2.8
通讯作者：
Borg, Bertil
中科院分区：
文献类型：
--
作者：
Elofsson, Helena;Van Look, Katrien J. W.;Borg, Bertil
三棘鱼Gasterosteus aculeatus的精子在卵巢液的存在下表现出延长的运动能力。卵巢液使精子在淡水中的活动能力从大约1分钟延长到几个小时，这一特性可能使棘鱼具有在所有盐度的沃茨中产卵的不同寻常的能力。该研究的目的是寻找卵巢液中负责延长精子活力的因素，并研究自然条件下卵巢液的可能生物学意义。为此，我们测定了卵巢液的离子含量（Na+，Cl-，Ca 2+和K+），并制备了离子型人工卵巢液。我们还制备了与卵巢液具有相同渗透压的甘露醇溶液，以区分离子和渗透效应。我们发现，在一定浓度范围内，离子人工液在延长精子活力和存活率方面与天然卵巢液同样有效，而甘露醇溶液的效果要差得多。通过将天然卵巢液或通过超滤除去大分子的卵巢液插入巢中，发现大分子有助于保留离子。我们还发现，卵巢液在水中，在低至0.75和1.56%的浓度，延长精子活力和离子（Na+）的浓度存在于巢产卵后15分钟对应于至少3%的卵巢液。之前的受精实验表明，刺鱼精子至少需要15分钟才能使一批所有卵子受精。这表明卵巢液在延长精子活力方面的作用是生物学相关的，并且这种作用是由液体的离子含量产生的。
Sperm of the three-spined stickleback Gasterosteus aculeatus display a prolonged motility in the presence of ovarian fluid. The ovarian fluid prolongs sperm motility in freshwater from approximately 1 min to several hours, a trait that possibly gives the stickleback its unusual ability to spawn in waters of all salinities. The aim of the study was to look for factor(s) within the ovarian fluid responsible for prolonging sperm motility as well as to investigate the possible biological importance of the ovarian fluid under natural conditions. To that end, we measured the ionic content (Na+, Cl-, Ca2+ and K+) of the ovarian fluid and prepared ionic artificial ovarian fluids. We also prepared a mannitol solution with the same osmolality as the ovarian fluid in order to distinguish between the ionic and osmotic effect. We found that the ionic artificial fluids were equally effective as the natural ovarian fluid in prolonging sperm motility and survival over a range of concentrations, whereas the mannitol solution was far less effective. By insertion of natural ovarian fluid or ovarian fluid from which macromolecules had been removed by ultra filtration in nests it was found that macromolecules help by retaining ions. We also found that ovarian fluid in water, at concentrations as low as 0.75 and 1.56%, prolonged sperm motility and that the concentration of ions (Na+) present in the nest 15 min after spawning corresponded to at least 3% ovarian fluid. Previous fertilisation experiments have shown that it takes at least 15 min for stickleback sperm to fertilise all eggs in a batch. This indicates that the role of ovarian fluid in prolonging the sperm motility is biologically relevant and that the effect is exerted by the fluid's ionic content.