水螅营养积累对基盘组织更新进程的影响

The effect of nutrition accumulation on the process of basal disc、renewal in hydra

目的观察大乳头水螅(Hydra magnipapillata)基盘组织更新进程,探讨水螅营养积累对基盘组织更新进程的影响。方法设定水螅喂食频率梯度(代表不同的营养积累水平),记录和观察喂食频率对水螅更新基盘组织进程的影响。通过ABTS细胞化学染色法检测水螅基盘分子标志物过氧化物酶的表达,观察水螅老基盘组织脱落后水螅体主体新生基盘组织的再生过程。结果喂食频率对水螅更新基盘组织进程有明显的影响。水螅基盘组织更新的标准过程如下:在一定的喂食频率下培养水螅,水螅体出芽区逐渐有芽体产生,随后在出芽区和基盘之间靠近芽体的位置出现缢痕,最后水螅体在缢痕处断裂为水螅体主体和老基盘组织两部分。缢痕断裂后对水螅体主体保持既定的喂食频率,其伤口能愈合但不能再生出新的基盘组织;对其降低喂食频率直至其伤口上方的芽体全部脱落后伤口处重新启动新生基盘组织的再生进程。另外,脱落的老基盘组织有两种不同的命运,即大部分老基盘组织不能发育成正常水螅体、最终解体;而小部分的老基盘组织能发育成正常的水螅体。结论水螅营养积累可能促进基盘组织更新进程,靠近断裂伤口处的芽体能抑制水螅体主体新生基盘的再生进程。

Objective To observe the process of basal disc renewal in Hydra magnipapillata and explore the effect of nutrition accumulation on the process of basal disc renewal in hydra. Methods The effect of feeding frequency, which represented different nutrition accumulation levels, on the process of hydra basal disc renewal was studied. Moreover, in order to observe whether new basal discs were regenerated or not, the cytochemical staining method based on substrate ABTS was used to reveal the expression of the peroxidase of basal discs. Results There was obvious effect of feeding frequency on the process of hydra basal disc renewal. The standard process was as follows： constriction appeared between budding region and basal disc after buds formed gradually under certain feeding frequency, and the hydra broke finally into two parts at the constriction. The new basal disc in the wound of the parent polyp did not regenerate when the parent polyp was also cultivated under certain feeding frequency after the hydra broke into two parts, but basal disc regeneration could restart after all buds near the wound detached from the parent polyp when the parent polyp was cultivated under lower feeding frequency. In addition, there were two different developmental patterns of old basal discs separated from the parent polyp： most old basal discs would decrease in size and finally degenerate, die and disintegrate, while a few old basal discs could regenerate into new normal hydra. Conclusion Higher nutrition accumulation levels stimulate hydra to renew basal discs, and the bud near the wound of the parent polyp suspends basal disc regeneration.