| Budget Amount *help |
¥18,200,000 (Direct Cost: ¥14,000,000、Indirect Cost: ¥4,200,000)
Fiscal Year 2014: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2013: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2012: ¥8,840,000 (Direct Cost: ¥6,800,000、Indirect Cost: ¥2,040,000)
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| Outline of Final Research Achievements |
In several vertebrate groups, post-copulatory sperm viability is prolonged by their storage in specialized organs within the female reproductive tract. In birds, ejaculated sperm can be stored in a quiescent stage within oviductal sperm storage tubules (SSTs), thereby preventing the loss of fertility for up to 15 weeks; however, the mechanism by which once-activated spermatozoa are rendered quiescent within SSTs remains a mystery. Here, we show that quail SSTs maintain a hypoxic niche and secrete lactic acid. Sperm immobility is induced by lactic acid through cytoplasmic acidification and flagellar dynein ATPase inactivation. The assertion that hypoxia played a role in the process of sperm storage was further supported by improved morphological preservation of ejaculated spermatozoa under hypoxic conditions at body temperature. Our results open up new opportunity for technological improvement in prolonging sperm longevity at ambient or body temperature.
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