Inductive eff ect of bioactive substances on strobilation of jellyfi sh Aurelia coerulea

The moon jellyfi sh Aurelia spp.is a worldwide distributed scyphozoan species that seasonally blooms in coastal waters.Although the strobilation is directly responsible for the scale of jellyfi sh bloom,the underlying mechanisms remain largely unknown.We exposed Aurelia coerulea polyps to 18 bioactive substances to test their ability to induce strobilation at the natural typically non-strobilation temperature of 21°C.Results revealed that A.coerulea polyps responded in four types.Type I—no change for estradiol,folic acid,iodine,retinoic acid,serotonin hydrochloride,and vitamin A.We suggested that 5-aza-2-deoxycytidine and N-acetyl-L-glutamic acid could not induce strobilation,since the percent of strobilated polyps in these two substances treatments was 3.3%and 1%,respectively.Type II—polyp body elongation for 3,5-diiodo-Ltyrosine,indole-3-acetic acid,L-dopamine,and noradrenaline treatments.Type III—transverse constrictions for L-thyroxine,progesterone,and melatonin treatments.Finally,Type IV—complete strobilation for 5-methoxy-2-methylindole,acetylcholine chloride,and indomethacin treatments,where the pre-strobilation periods were 2,4,and 2 days,and the mean numbers of ephyrae released per strobila were 4.7,5.7,and 5.7,respectively.The results reveal that indole derivatives,which contained methoxy or methyl pharmacophore,were the common strobilation inducer in the genus Aurelia.Iodinated organic compounds,catecholamine,acetylcholine chloride,and retinoic acid are species-specifi c strobilation inducer.Therefore,A.coerulea strobilation is regulated by neuronal and endocrine processes.Our fi ndings provide clues in understanding the mechanism of strobilation and contribute to developing specifi c strobilation antagonists in controlling moon jellyfi sh blooms.

Metabolomics provide insights into the endogenous mechanism of strobilation in the scyphozoan jellyfi sh Rhopilema esculentum

Strobilation is a well-organized metamorphosis process in scyphozoan jellyfi sh,through which the benthic polyp develops into the pelagic medusa.So far,knowledge on the molecular mechanisms behind the drastic morphological and physiological changes remains limited.In the present study,the metabolic profi les in polyp and strobila stages of jellyfi sh Rhopilema esculentum were examined using ultra-performance liquid chromatography coupled to a mass spectrometer.A total of 3071 metabolites with putative annotation were detected,of which 167 were identifi ed as diff erential metabolites between the polyp and strobila.Among the metabolites,31 signifi cantly decreased and 136 signifi cantly increased in abundance in the strobila.Thyroxin,one of the previously proposed strobilation inducer of Aurelia,was not detected in this study.The indole-containing compounds are known for triggering strobilation in Discomedusae.Two indole derivatives and an indole-isomer containing metabolite were detected among the most signifi cantly increased metabolites,which may be potential endogenous molecules for strobilation initiation.The membrane-associated phospholipids and the infl ammation and oxidative stress-related eicosanoids were found to have signifi cant changes.Although the functions of these metabolites in strobilation are not yet completely known,they provide some clues to the induction of the process of strobilation and metabolic responses that take place during strobilation.

基于人的脆弱性的社会保障元理论研究

现代社会保障制度建立以来,理论研究在推动制度确立、促进政策调整中具有重要作用。本文从生理、经济、社会方面研究了人的生命周期中的脆弱性累积效应,借助“水母型”社会结构,静态地展现社会中低龄、青年、中年、老龄的群体分布,以及低龄、老龄群体的弱势状态;动态地跟踪人的“弱-强-弱”变化轨迹。随着经济社会发展,家庭、互助、市场等保障机制都难以胜任覆盖全体社会成员的保障功能,这就需要建立全新的社会保障机制。论文在建构基于牛顿-莱布尼茨公式的社会保障微积分模型的基础上,对社会保障的元理论进行探讨,进而得出:对青年、中年要强化基于就业的社会保障,特别是当前大量且复杂的平台就业者的社会保障;确保“老弱”因缴税/费或公民社会权的社会保障;为了未来公民的健康成长要确保“幼弱”的社会保障(福利)。由于社会保障是生命周期过程中收入再分配的一种方式,政府必须科学理性地设计政策,以确保个人和家庭对基本生活需求的保障。