. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 64 W. R. ECKBERG AND M. E. PEROTTI. I 10 Micromolar Quercetin 100 FIGURE 1. Effect of quercetin on fertilization of Lytechinus pictus eggs. Eggs were mixed with various concentrations of quercetin in ASW and inseminated five min later. Eggs were examined by phase-contrast microscopy and scored as fertilized if they showed elevated fertilization envelopes, post- fertilization nuclear changes and cleavage. quickly. Quercetin significantly inhibited fertilization in Strongylocentrotus at 14°C when added as late as 20 s after in
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 64 W. R. ECKBERG AND M. E. PEROTTI. I 10 Micromolar Quercetin 100 FIGURE 1. Effect of quercetin on fertilization of Lytechinus pictus eggs. Eggs were mixed with various concentrations of quercetin in ASW and inseminated five min later. Eggs were examined by phase-contrast microscopy and scored as fertilized if they showed elevated fertilization envelopes, post- fertilization nuclear changes and cleavage. quickly. Quercetin significantly inhibited fertilization in Strongylocentrotus at 14°C when added as late as 20 s after insemination, whereas additions 40 s after insem- ination were ineffective. Eggs which became fertilized in quercetin subsequently cleaved, indicating that the drug did not directly affect either sperm incorporation, pronuclear migration and fusion, or cell division. Quercetin treatment was reversible. Sperm or eggs pretreated with 100 ^M quer- cetin and washed with ASW were fertile. Furthermore, inseminated eggs in quercetin could become activated if the quercetin was subsequently diluted with ASW. Figure 3 shows that quercetin inhibited sperm motility. At fertilization-inhibiting concentrations, sperm motility was reduced within 3 min and ceased with an I50 (time of 50% inhibition) of ca. 10 min. Lower concentrations of quercetin had no significant effect on sperm motility. Light and electron microscope analyses showed that sperm could undergo the acrosome reaction in quercetin and bind to and probably penetrate egg vitelline layers but could not activate eggs. Control Lytechinus eggs fixed 30 s after insem- ination had begun to undergo the cortical reaction, but still had numerous sperm bound (Fig. 4). Quercetin-treated eggs fixed at the same time after insemination showed bound sperm but no evidence of egg activation (Fig. 5). Electron microscopy confirmed the fact that egg activation had not begun since all cortical granules were intact (Fig. 6). Electron microscopy also sh
Size: 1601px × 1561px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
