利用秀丽线虫进行纳米材料安全性评价研究进展

鉴于纳米材料易于进入生物体内且已经进入生活环境,有关其生物安全性及相应毒理学研究日益受到关注〔1-2〕。有关纳米材料环境暴露的致生物毒性,利用各种离体(in vitro)与在体(in vivo)生物体系已经证明了环境暴露确实存在安全     

重金属暴露可以改变秀丽线虫的脂肪积累

目的：研究重金属暴露对秀丽线虫脂肪积累的急性中毒效应,鉴定重金属暴露秀丽线虫中发生表达模式改变的与脂肪酸代谢相关的基因。方法：银、镉、铬、铜、汞、锰和锌作为测试重金属,Nile Red荧光探针染色分析重金属暴露线虫肠道的脂肪酸含量变化,并测定重金属暴露线虫中脂肪酸代谢相关基因的转录水平变化。结果：在所分析重金属中,高浓度银、铬和铜暴露可以显著诱导线虫肠道脂肪积累的增加,而高浓度镉暴露可以显著降低线虫肠道脂肪的积累。而且,与对照组相比,高浓度的银和铬暴露不明显影响基因pod-2、gei-7、lbp-8、gpd-3、W05G11.6、C03H5.4和C07E3.9的表达水平,而在暴露的线虫动物中,基因fat-5、fat-6和fat-7的表达水平显著升高,lbp-1、acs-2和ech-1的表达水平显著降低。结论：高浓度银、铬、铜和镉暴露可以导致异常的秀丽线虫肠道的脂肪积累变化,其中高浓度银和铬暴露导致线虫脂肪积累增加的主要原因可能归因于暴露动物体内脂肪酸去饱和与线粒体β-氧化代谢途径以及脂肪酸结合能力的异常。     

利用排泄行为参数评价重金属暴露对于秀丽线虫代谢状态的毒害

目的：研究重金属暴露对秀丽线虫排泄行为的影响。方法：用于分析的CdCl2、CrCl2、HgCl2和Pb（NO3）2溶液浓度分别为50、100、150和200μmol.L-1。参数平均排泄循环长度用于评价重金属暴露秀丽线虫的代谢状态改变。线性回归用于分析平均排泄循环长度与暴露重金属浓度之间、暴露动物中平均排泄循环长度和咽泵运动速率之间的关联。结果：所有分析浓度的汞和铅暴露以及浓度为100μmol.L-1到200μmol.L-1的镉和铬暴露均可以显著增加线虫的平均排泄循环长度。线虫平均排泄循环长度具有伴随重金属暴露浓度改变而变化的特点,且平均排泄循环长度显著相关于所暴露重金属的浓度。在重金属暴露的线虫中,咽泵运动速率还显著相关于平均排泄循环长度。此外,汞和铅暴露对于线虫排泄行为的影响远比铬和镉的暴露严重。结论：参数平均排泄循环长度可以有效评价重金属暴露对线虫代谢状态的毒害,而且在重金属暴露线虫中可以观察到平均排泄循环长度与咽泵运动速率之间的显著相关性。     

质膜相关的SNAREs syntaxin/UNC-64与SNAP-25/RIC-4蛋白调控秀丽线虫的脂肪积累(英文)

目的研究神经突触组装与功能调控相关基因是否参与秀丽线虫的脂肪积累调节。方法分析神经突触组装与功能调控相关基因突变体的脂肪积累变化,进而观察SNAREs syntaxin/unc-64和SNAP-25/ric-4基因与daf-2、daf-7、nhr-49、sbp-1及mdt-15所介导的信号通路在调控脂肪积累上的遗传关系。对unc-64与ric-4基因进行组织特异性活性分析,以确定它们在神经系统与肠道内对脂肪积累的影响。结果突触前为神经突触组装所必需的基因的突变并未明显影响脂肪积累。对调控神经突触功能的基因进行分析的结果显示,SNAREssyntaxin/unc-64与SNAP-25/ric-4基因均参与了脂肪积累的调节。利用苏丹黑染色与尼罗红标记法观察到unc-64与ric-4突变体肠道中脂肪积累显著增加,而unc-64与ric-4突变体中积累的脂肪颗粒并未出现尺寸的显著变化。在神经系统与肠道中,unc-64基因的表达均能显著降低unc-64突变体动物的脂肪积累,而基因ric-4在神经系统的表达则可以完全恢复ric-4突变体动物的脂肪积累。遗传分析表明,unc-64与ric-4对脂肪积累的调控独立于daf-2...     

UNC-64 and RIC-4, the plasma membrane-associated SNAREs syntaxin and SNAP-25, regulate fat storage in nematode Caenorhabditis elegans

Objective

To investigate whether genes required for synaptogenesis and synaptic function are also involved in fat storage control in Caenorhabditis elegans.

Methods

Fat storage was examined in mutants of genes affecting the synaptogenesis and synaptic function. In addition, the genetic interactions of SNAREs syntaxin/unc-64 and SNAP-25/ric-4 with daf-2, daf-7, nhr-49, sbp-1 and mdt-15 in regulating fat storage were further investigated. The tissue-specific activities of unc-64 and ric-4 were investigated to study the roles of unc-64 and ric-4 in regulating fat storage in the nervous system and/or the intestine.

Results

Mutations of genes required for the formation of presynaptic neurotransmission site did not obviously influence fat storage. However, among the genes required for synaptic function, the plasma membrane-associated SNAREs syntaxin/unc-64 and SNAP-25/ric-4 genes were involved in the fat storage control. Fat storage in the intestinal cells was dramatically increased in unc-64 and ric-4 mutants as revealed by Sudan Black and Nile Red strainings, although the fat droplet size was not significantly changed. Moreover, in both the nervous system and the intestine, expression of unc-64 significantly inhibited the increase in fat storage observed in unc-64 mutant. And expression of ric-4 in the nervous system completely restored fat storage in ric-4 mutant. Genetic interaction assay further indicated that both unc-64 and ric-4 regulated fat storage independently of daf-2 [encoding an insulin-like growth factor-I (IGF-I) receptor], daf-7 [encoding a transforming growth factor-β (TGF-β) ligand], and nhr-49 (encoding a nuclear hormone receptor). Besides, mutation of daf-16 did not obviously affect the phenotype of increased fat storage in unc-64 or ric-4 mutant. Furthermore, unc-64 and ric-4 regulated fat storage probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways. In addition, fat storage in unc-64; ric-4 was higher than that in either unc-64 or ric-4 single mutant nematodes, suggesting that unc-64 functions in parallel with ric-4 in regulating fat storage.

Conclusion

The plasma membrane-associated SNAREs syntaxin/unc-64 and SNAP-25/ric-4 function in parallel in regulating fat storage in C. elegans, probably through the ARC105/mdt-15- and SREBP/sbp-1-mediated signaling pathways.     

汞暴露导致秀丽线虫后代中出现可传递的表型和行为缺陷

目的：研究汞暴露秀丽线虫表型和行为缺陷在后代中的可传递特性。方法：寿命、身体尺寸、身体弯曲频率、头部摆动频率和化学趋向可塑性用于汞急性毒害评价,并进一步分析表型和行为缺陷从汞暴露的当代到后代的可传递特性。结果：汞暴露能够引起包括寿命、身体尺寸、身体弯曲频率、头部摆动频率和化学趋向可塑性等参数在内的多重生物学缺陷,且其毒害与所暴露汞浓度之间密切相关。大部分毒害能够从暴露线虫当代传递给后代。汞暴露对线虫后代寿命的毒害不能够明显恢复。汞暴露线虫后代身体尺寸的缺陷甚至比当代更为严重。此外,高浓度汞暴露通常导致非常纤细的线虫动物出现,且在后代中可观察到更多具有这种表型的线虫。汞暴露导致的线虫身体弯曲和头部摆动频率缺陷在后代中可以大部分或者完全恢复。尽管化学趋向可塑性在汞暴露线虫后代中能够部分恢复,但是化学趋向可塑性仍受到严重的破坏。结论：汞暴露引起的多重生物学毒害可以从暴露当代传递给它们的后代,并且在后代中出现的一些缺陷甚至比当代更为严重。