Circadian rhythm of glycoprotein secretion in the vas deferens of the moth, Spodoptera littoralisReportar como inadecuado

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BMC Physiology

, 2:15

First Online: 13 September 2002Received: 20 August 2002Accepted: 13 September 2002


BackgroundReproductive systems of male moths contain circadian clocks, which time the release of sperm bundles from the testis to the upper vas deferens UVD and their subsequent transfer from the UVD to the seminal vesicles. Sperm bundles are released from the testis in the evening and are retained in the vas deferens lumen overnight before being transferred to the seminal vesicles. The biological significance of periodic sperm retention in the UVD lumen is not understood. In this study we asked whether there are circadian rhythms in the UVD that are correlated with sperm retention.

ResultsWe investigated the carbohydrate-rich material present in the UVD wall and lumen during the daily cycle of sperm release using the periodic acid-Shiff reaction PAS. Males raised in 16:8 light-dark cycles LD showed a clear rhythm in the levels of PAS-positive granules in the apical portion of the UVD epithelium. The peak of granule accumulation occurred in the middle of the night and coincided with the maximum presence of sperm bundles in the UVD lumen. These rhythms persisted in constant darkness DD, indicating that they have circadian nature. They were abolished, however, in constant light LL resulting in random patterns of PAS-positive material in the UVD wall. Gel-separation of the UVD homogenates from LD moths followed by detection of carbohydrates on blots revealed daily rhythms in the abundance of specific glycoproteins in the wall and lumen of the UVD.

ConclusionSecretory activity of the vas deferens epithelium is regulated by the circadian clock. Daily rhythms in accumulation and secretion of several glycoproteins are co-ordinated with periodic retention of sperm in the vas deferens lumen.

Electronic supplementary materialThe online version of this article doi:10.1186-1472-6793-2-15 contains supplementary material, which is available to authorized users.

and JM Giebultowicz contributed equally to this work.

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Autor: P Bebas - E Maksimiuk - B Gvakharia - B Cymborowski - JM Giebultowicz


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