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Titolo:
SURFACE ULTRASTRUCTURE OF PADDLEFISH EGGS BEFORE AND AFTER FERTILIZATION
Autore:
LINHART O; KUDO S;
Indirizzi:
UNIV S BOHEMIA,DEPT FISH GENET & BREEDING,RES INST FISH CULTURE & HYDROBIOL CZ-38925 VODNANY CZECH REPUBLIC GUNMA UNIV,SCH MED,DEPT ANAT MAEBASHI GUMMA 371 JAPAN
Titolo Testata:
Journal of Fish Biology
fascicolo: 3, volume: 51, anno: 1997,
pagine: 573 - 582
SICI:
0022-1112(1997)51:3<573:SUOPEB>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELECTRON-MICROSCOPIC OBSERVATIONS; SPERM PENETRATION; FINE-STRUCTURE; CARP EGGS; ENTRY; FISH; CONE;
Keywords:
MICROPYLE; EGG; SPERM PENETRATION; PADDLEFISH; SCANNING ELECTRON MICROSCOPY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
O. Linhart e S. Kudo, "SURFACE ULTRASTRUCTURE OF PADDLEFISH EGGS BEFORE AND AFTER FERTILIZATION", Journal of Fish Biology, 51(3), 1997, pp. 573-582

Abstract

The surface ultrastructure of eggs of the paddlefish Polyodon spathula was investigated by scanning electron microscopy. Mature eggs of paddlefish possess four to 12 micropyles in the animal polar region. There are sperm entry sites in the egg surface under the micropyles which consist of tufts of microvilli. Five to nine sperm entry sites were observed on mature eggs. Probably, the number of sperm entry sites corresponds to the number of micropyles. In a few eggs, 1 min after fertilization the ball-like enlarged top of a cytoplasmic process (probably afull-grown fertilization cone) had reached the external aperture or the canal of several micropyles. In other micropyles of the same egg, afew smaller cytoplasmic processes or flocculent material were found in the micropylar canal. With one exception, no sperm tails were found there. The formation of the full-grown cytoplasmic process is possiblyinitiated before the cortical reaction has started in an area of the animal hemisphere. Three, 10 and 20 min after fertilization, the uneven surface of the cortical cytoplasm in the animal polar region rose gently where microvilli were much less than the in other area and together with a secondary polar body at the latter stage. Taken together, paddlefish eggs may have sperm entry sites corresponding to the number of micropyles and respond to the stimulus of fertilization by forming afew cytoplasmic processes - fertilization cones (larger and smaller). Sperm penetration into the egg may be achieved at an earlier stage offertilization (sperm-egg contact), as inferred from the fact that a secondary polar body was formed at the 20-min stage irrespective of theexceptional finding of the sperm tail. (C) 1997 The Fisheries Societyof the British Isles.

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Documento generato il 01/10/20 alle ore 16:12:35