铜对秀丽隐杆线虫毒性效应的研究

为了阐明铜(Cu)对秀丽隐杆线虫Caenorhabditis elegans长期作用的毒性效应,对实验室多代筛选的耐铜型秀丽隐杆线虫进行了寿命、衰老、发育、生殖和运动等生物学指标的研究.结果显示耐铜型秀丽隐杆线虫与野生型秀丽隐杆线虫相比其寿命缩短、衰老提前、个体发育受到抑制,且出现繁殖率降低、生殖能力减弱、运动行为存在障碍等一系列生理变化.本文为理解与阐明Cu的毒性效应提供了实验资料,有助于深入开展Cu毒性机理的研究.     

秀丽隐杆线虫模型在抗衰老研究中的应用

随着人口老龄化问题的凸显,衰老相关的研究越来越被重视。秀丽隐杆线虫（Caenorhabditis elegans）是抗衰老研究领域中非常重要的生物模型,具有生命周期短、易于培养和观察等优点,但与其他哺乳动物模型相比仍有一些局限性,如DNA甲基化的缺乏等。本文主要综述了秀丽隐杆线虫模型在抗衰老研究和药物筛选中的应用,包括抗衰老药物对线虫寿命和抗性的测定与评估、药物筛选以及健康衰老研究中的应用,并概括了该模型的优势和局限性,为秀丽隐杆线虫模型在抗衰老研究中的应用提供理论依据。     

空间环境对秀丽线虫行为及生长发育研究进展

与秀丽线虫有关的研究开始于20世纪60年代,秀丽线虫作为模式生物是第一个完成基因测序的多细胞生物,普遍应用于各种环境对生理和行为学研究中。空间环境以微重力、强辐射作为特点,对秀丽线虫的生理及行为产生很大影响。本文总结了微重力和辐射引起秀丽线虫运动能力、寿命、能量代谢等方面基因表达变化的研究成果。秀丽线虫与人类的序列相似性高达40%,空间环境对秀丽线虫行为及生长发育的研究为空间环境对人类健康影响研究提供数据支持,也为空间损伤修复研究提供理论基础。     

必需氨基酸延缓秀丽隐杆线虫衰老的研究

利用模式生物秀丽隐杆线虫,考察8种人体必需氨基酸对衰老的影响。首先建立秀丽隐杆线虫寿命模型,以雷帕霉素为阳性对照药,分别考察8种必需氨基酸对线虫生存时间的影响。再用筛选出的氨基酸处理线虫21d,通过秀丽隐杆线虫-绿脓杆菌感染模型,考察氨基酸对线虫的抗感染能力的影响,利用实时荧光定量Real-Time RT-PCR方法检测氨基酸处理线虫后DAF-16/FOXO下游基因和免疫相关基因的表达水平。结果表明8种必需氨基酸中苏氨酸和异亮氨酸既能延长野生型线虫的寿命又能延长daf-16突变型线虫的寿命,同时还能增强秀丽隐杆线虫抗绿脓杆菌感染的能力,并提高免疫相关基因lys-7、clec-67的表达水平,而DAF-16/FOXO下游基因表达没有明显变化。因此苏氨酸和异亮氨酸能延长线虫寿命、提高抗感染能力,且对线虫寿命的延长作用不完全依赖于DAF-16/FOXO转录因子。     

山楂提取物对急性损伤线虫的保护作用

以秀丽隐杆线虫(Canorhabditis elegans)为模式生物研究山楂提取物(Haworth fruit extract,HFE)对其急性氧化损伤的保护作用及其可能的作用机制。饲喂线虫于含有不同浓度(0、25、50和100μg/m L)HFE的NGM(Nematode growth medium)培养基中,研究HFE对线虫急性应激耐受能力的影响。结果显示,饲喂HFE后,秀丽线虫表现出比正常组更高的寿命,并且在胡桃醌氧化应激、热应激及紫外辐射应激实验中寿命均明显延长,荧光显微镜观察发现HFE组线虫的脂褐素自发荧光明显减弱,并且与HFE浓度呈剂量依赖效应。HFE能够显著延长秀丽隐杆线虫的寿命,同时对多种氧化损伤具有较好的保护作用,改善机体的抗氧化能力,有效延缓衰老。     

二甲基亚砜对秀丽线虫运动、个体发育和生殖的影响

本研究探讨了不同浓度二甲基亚砜(dimethyl sulfoxide, DMSO)对秀丽线虫运动、个体发育以及生殖的影响。结果显示:DMSO浓度≥2.5%时,线虫咽泵运动次数显著下降;DMSO浓度≤0.5%时,线虫头部摆动次数显著增加;DMSO浓度≤2.5%时,线虫体长和体宽无明显影响,浓度为5.0%时,抑制线虫个体发育作用明显;DMSO浓度0.5%,线虫子宫内怀卵数增加,而后代数目减少;各试验浓度DMSO对单侧性腺臂卵母细胞数目均无显著影响。综上所述,DMSO对秀丽线虫具有一定毒性作用,且对不同指标产生毒性的浓度阈值不同,在以线虫为模型的药物研究中,为排除DMSO对线虫的毒性作用给试验结果造成的影响,助溶剂DMSO的最佳使用浓度应为0.5%,本研究为今后对秀丽线虫的研究提供研究数据。     

肠道细菌相关代谢产物脱氧胆酸的 量效和时效对秀丽隐杆线虫生长发育的影响

目的观察脱氧胆酸对线虫生存和生长发育的影响,了解脱氧胆酸的作用。方法实验对象分为对照组和实验组,其中实验组分为低浓度组、中浓度组和高浓度组。将L1期线虫放于实验组中培养48 h后观察不同浓度的脱氧胆酸对线虫生长的影响,在D0期(幼年成虫期)、D4期(线虫成年后第4天)、D6期(线虫成年后第6天)观察不同浓度的脱氧胆酸对线虫运动能力、抗感染能力、寿命和生殖能力的影响。结果不同浓度的脱氧胆酸对线虫生长的影响未见明显差异。在不同时间、不同浓度脱氧胆酸的作用下,线虫运动能力随着剂量的增加和时间的延长而降低,中高浓度脱氧胆酸可缩短线虫的寿命和降低抗感染能力,并呈剂量依赖性。高浓度的脱氧胆酸可以减少线虫的子代及缩短线虫的产卵时间。结论脱氧胆酸不影响线虫的生长。大剂量的脱氧胆酸对线虫可能存在量效和时效的生殖毒性作用和慢性毒性作用,缩短线虫的寿命,降低线虫的运动及抗感染能力,其作用机制仍需进一步研究。     

秀丽隐杆线虫体内脂肪染色方法的探究

近几十年来,秀丽隐杆线虫(Caenorhabditis elegans)因其结构简单、通体透明、生命周期短和易于培养,常作为一种模式生物被广泛用于现代发育生物学、遗传学、抗衰老和及脂肪调控等方面的研究。本文探索了一种对秀丽隐杆线虫体内脂肪的油红O染色方法,利用1%Triton X-100的透过作用,线虫体内脂滴可被油红O更好的着色,镜下观察颜色鲜红,染色效果较好,为以后研究线虫脂肪调控奠定了基础。     

细菌与秀丽隐杆线虫之间互作关系的研究进展

秀丽隐杆线虫(Caenorhabditis elegans)以其个体小、易培养、生活周期短等优势成为生物发育、衰老、神经及免疫相关机制研究的模式生物.它在实验室培养时主要靠饲喂大肠杆菌OP50,有报道,细菌及其代谢物对线虫的代谢、行为和寿命有至关重要的影响.因此,作为一个遗传模型,秀丽隐杆线虫可以帮助研究微生物与宿主相...     

利用模式生物线虫评价精对苯二甲酸废水的毒性

应用模式生物秀丽隐杆线虫,通过生命周期、半数致死天数、生殖速度、产卵数、头部摆动频率和身体弯曲次数等指标对精对苯二甲酸(PTA)废水毒性进行了研究.结果表明,与对照组相比,660 mg·L^-1 PTA废水暴露下的线虫生命周期有一定的延长,产卵时间延迟,头部摆动频率降低,身体弯曲次数减少(P<0.05),且PTA废水对线虫生殖能力的影响极显著(P<0.01),暴露于废水中的线虫产卵数大约只有正常产卵数的1/4.最敏感效应指标——产卵数,有望成为该类废水毒性预警预报的潜在生物标志物.     

Viili中胞外多糖的分离纯化及对秀丽线虫寿命的影响

采用Sevage法脱蛋白、乙醇沉淀、DEAE-纤维素离子交换柱层析和Sephadex G-200分子筛层析法,从Viili中分离纯化得到Viili中乳酸菌胞外多糖(EPS).采用秀丽线虫进行寿命实验,观察Viili EPS延长秀丽线虫寿命的效果,在20℃下,饲喂Viili EPS 200 mg·L-1组秀丽线虫的平均寿...     

Antifungal Activity of Schinifoline Against Candida Albicans in Caenorhabditis Elegans

Zanthoxylum schinifolium has been used as spices and traditional medicine in China for hundreds of years. A variety of active substances have been isolated from Zanthoxylum schinifolium using biological and chemical techniques. Among these substances, the effect of schinifoline has gradually attracted much attention. Candida albicans is one of the most common pathogens isolated from the gastrointestinal tract, vagina, and mouth in healthy individuals. In a healthy population, there are various mechanisms in host, such as the microbial flora, the epithelial barriers, and the innate immune system, that can control the presence of Candida albicans. However, when host immunity is compromised, an invasive fungal infection is more likely to occur. In this study, we explored the antifungal activity of schinifoline against Candida albicans in Caenorhabditis elegans. To determine the optimal concentration of schinifoline, we investigated the lifespan, defecation cycle and locomotion behavior of Caenorhabditis elegans after treatment with schinifoline. In addition, we examined colony formation in the intestine of Caenorhabditis elegans after Candida albicans infection. The results indicated that 100 and 200 mg/L of schinifoline could prolonged the lifespan, shorten the defecation cycle and increased the locomotion behavior of Caenorhabditis elegans, with 100 mg/L of schinifoline being the optimal concentration. Moreover, 100 mg/L of schinifoline increased the lifespan of Caenorhabditis elegans after infection and inhibited the colony formation of Candida albicans in Caenorhabditis elegans intestine. Therefore, we concluded that schinifoline exhibits anti-fungal effects and its potential use as natural drugs should be further explored in future studies.     

Differential effects of resveratrol and SRT1720 on lifespan of adult Caenorhabditis elegans

Resveratrol and SRT1720 have been shown to act as sirtuin activators that may ameliorate type 2 diabetes and metabolic diseases in mice. Moreover, resveratrol extends lifespan in model organisms like C. elegans, N. FURZERI, and possibly D. melanogaster. The aim of the study was to test whether pharmacological concentrations of resveratrol and SRT1720 are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Several hundreds of adult C. ELEGANS roundworms were maintained on agar plates and fed E. COLI strain OP50 bacteria. Resveratrol (5 micromolar, 500 nanomolar) or SRT1720 (1 micromolar, 100 nanomolar) was applied to the agar to test whether they may promote longevity by quantifying survival in the presence and absence of the respective compounds. At a dose of 5 micromolar, which is pharmacologically relevant and 20 times lower than previously published concentrations, resveratrol significantly extends C. elegans lifespan by 3.6% (mean lifespan) and 3.4% (maximum lifespan). By unexpected contrast, SRT1720, which was previously proposed to be several hundred times more active than resveratrol, did not extend lifespan at none of the concentrations tested. Thus, in the model organisms C. elegans, resveratrol is capable of promoting longevity at a concentration that pharmacologically relevant and 20 times lower than previously published doses. The sirtuin activator SRT1720 did not extend lifespan, suggesting that in C. elegans, some relevant effects of resveratrol cannot be mimicked by SRT1720.     

A steroid hormone that extends the lifespan of Caenorhabditis elegans

Removing the germline of Caenorhabditis elegans extends lifespan. This lifespan extension requires the nuclear receptor DAF-12 and the cytochrome P450 DAF-9, suggesting that a lipophilic hormone is involved. Here we show that C. elegans contains several hormonal steroids that are also present in humans, including pregnenolone (3beta-hydroxy-pregn-5-en-20-one; PREG) and other pregnane and androstane derivatives. We find that PREG can extend the lifespan of C. elegans. Moreover, PREG levels rise when the germline is removed in a daf-9-dependent fashion. PREG extends the lifespan of germline-defective daf-9 mutants dramatically, but has no effect on daf-12 mutants. Thus, germline removal may extend lifespan, at least in part, by stimulating the synthesis of PREG.     

No increase in lifespan in Caenorhabditis elegans upon treatment with the superoxide dismutase mimetic EUK-8

The superoxide dismutase mimetic EUK-8 has been reported to extend lifespan in the nematode Caenorhabditis elegans. However, in five trials administering EUK-8 in liquid culture with E. coli, and two trials using defined liquid medium, we observed no increase in C. elegans lifespan. Instead we saw a dose-dependent reduction of lifespan and fertility. We conclude that extension of C. elegans lifespan by EUK-8 may only occur under very particular culture conditions.     

Variable pathogenicity determines individual lifespan in Caenorhabditis elegans

A common property of aging in all animals is that chronologically and genetically identical individuals age at different rates. To unveil mechanisms that influence aging variability, we identified markers of remaining lifespan for Caenorhabditis elegans. In transgenic lines, we expressed fluorescent reporter constructs from promoters of C. elegans genes whose expression change with age. The expression levels of aging markers in individual worms from a young synchronous population correlated with their remaining lifespan. We identified eight aging markers, with the superoxide dismutase gene sod-3 expression being the best single predictor of remaining lifespan. Correlation with remaining lifespan became stronger if expression from two aging markers was monitored simultaneously, accounting for up to 49% of the variation in individual lifespan. Visualizing the physiological age of chronologically-identical individuals allowed us to show that a major source of lifespan variability is different pathogenicity from individual to individual and that the mechanism involves variable activation of the insulin-signaling pathway.