CIL:502, Patiria miniata, sperm. In Cell Image Library

Echinoderm sperm nuclei are unusual in that chromatin fibers are clearly seen, allowing their diameter to be accurately determined. Here, sperm from the starfish P. miniata were treated to remove the outer membrane, cryo-fixed by plunging into liquid ethane, freeze-substituted in acetone and low-temperature embedded in Lowicryl K11M. Thin sections were stained with uranyl acetate, and examined using a FEI CM10 TEM operated at 100KV. This image shows the cup-shaped nucleus surrounding the acrosome. Flagellar axonemes are also present. Chromatin fibers in the nucleus are clearly visualized.

棘皮动物的精子核具有特殊性：其染色质纤维清晰可辨，可实现直径的精准测定。本研究以海星P. miniata的精子为材料，先对外膜进行去除处理，随后通过浸入液态乙烷完成冷冻固定，在丙酮中进行冷冻置换，再使用Lowicryl K11M进行低温包埋。超薄切片经醋酸铀染色后，采用工作电压为100kV的FEI CM10型透射电子显微镜进行观测。本图像展示了环绕顶体的杯状精子核，同时可见鞭毛轴丝，细胞核内的染色质纤维清晰可见。