文蛤肉水解液的致突变性

目的评价文蛤肉水解液的致突变性,为文蛤的开发利用提供实验数据。方法采用Ames试验、小鼠嗜多染红细胞骨髓微核试验和CHL细胞体外染色体畸变试验3项致突变性试验,检测文蛤肉水解液有无致突变作用。结果 Ames试验中文蛤肉水解液各剂量组回变菌落数均在正常范围内,均未超过自发回变菌落数的2倍,在加与不加S9时5株试验菌株结果为阴性。CHL细胞体外染色体畸变试验,文蛤肉水解液各剂量组的染色体畸变率与阴性对照组比较,差异无显著性(P0.05),结果为阴性。小鼠骨髓微核试验,各剂量组的微核率与阴性对照组比较,差异无显著性(P0.05),结果为阴性。结论在本试验条件和范围下,文蛤肉水解液未见潜在的致突变作用。     

Ames试验假阳性的判断方法

目的:确立一种判断Ames试验假阳性的可靠方法。方法:在Ames平皿掺入试验中发现经受试物处理的TA97和TA1535的菌落数相比溶媒对照组明显增加,为了证实其是因为受试物致突变性导致的回变菌落数增加还是由受试物毒性导致的菌落数增加,对分别经受试物和阳性对照物处理的Ames菌落进行增菌培养后接种于无组氨酸的培养基上,观察比较细菌的生长情况。结果:经受试物处理的菌株不能生长在无组氨酸的培养基中,而经阳性对照物处理的菌株则可以生长在无组氨酸的培养基上,说明经受试物处理的菌株没有发生突变。结论:此方法能可靠地验证菌株是否为突变菌株,由本研究可以发现经受试物处理的菌株没有发生突变,Ames平皿掺入试验中所观察到的菌落数增加是由于受试物毒性造成的假阳性。     

两种Ames试验方法在槲皮素致突变试验中灵敏度的研究

目的:通过传统Ames试验与改进彷徨试验对槲皮素的致突变试验结果,比较两种试验的灵敏度。方法:Ames试验方法采用平板掺入法,选择3.2、16、80、400、2000μg/mL 5个剂量组的槲皮素在有或无代谢话化条件下处理鼠伤寒沙门氏菌株TA98和TA100 48小时后计数回复突变菌落数;改进彷徨试验采用96孔板法,选择0.128、0.64、3.2、16、80μg/mL 5个剂量组的槲皮素在有或无代谢活化条件下处理鼠伤寒沙门氏菌株TA98和TA100 24小时后计数变色孔数。结果:Ames试验结果显示槲皮素在80-2000μg/mL回复突变菌落数明显增加并超过对照2倍并有明显剂量反应关系,Ames试验结果阳性;改进彷徨试验结果显示槲皮素在0.64-80μg/mL变色孔数明显增加(P<0.01),并有剂量反应关系,结果为阳性;而在0.64-16μg/mL剂量下,改进彷徨试验能检测出阳性结果,而Ames试验未检测出阳性结果。结论:在较低浓度时,改进彷徨试验能检测出Ames试验检测不出的阳性结果,表明改进彷徨试验灵敏度较Ames试验高。     

两种Ames试验方法在槲皮素致突变试验中灵敏度的研究

目的:通过传统Ames试验与改进彷徨试验对槲皮素的致突变试验结果,比较两种试验的灵敏度.方法:Ames试验方法采用平板掺入法,选择3.2、16、80、400、2000μg/mL 5个剂量组的槲皮素在有或无代谢话化条件下处理鼠伤寒沙门氏菌株TA98和TA 100 48小时后计数回复突变菌落数;改进彷徨试验采用96孔板法,选择0.128、0.64、3.2、16、80μg/mL 5个剂量组的槲皮素在有或无代谢活化条件下处理鼠伤寒沙门氏菌株TA98和TA100 24小时后计数变色孔数.结果:Ames试验结果显示槲皮素在80-2000μg/mL回复突变菌落数明显增加并超过对照2倍并有明显剂量反应关系,Ames试验结果阳性;改进彷徨试验结果显示槲皮素在0.64-80μg/mL变色孔数明显增加(P＜0.01),并有剂量反应关系,结果为阳性;而在0.64-16μg/mL剂量下,改进彷徨试验能检测出阳性结果,而Ames试验未检测出阳性结果.结论:在较低浓度时,改进彷徨试验能检测出Ames试验检测不出的阳性结果,表明改进彷徨试验灵敏度较Ames试验高.     

蕨菜乙醇提取物降尿酸作用机理及肾保护作用研究北大核心CSCD

为研究蕨菜乙醇提取物降尿酸作用机理及其肾保护作用,将蕨菜乙醇提取物灌胃模型小鼠1周,于给药第3 d,氧嗪酸钾灌胃复制高尿酸血症小鼠模型,检测血清尿酸水平、血及肝脏黄嘌呤氧化酶活性,探讨其治疗高尿酸血症作用机理;蕨菜乙醇提取物灌胃模型小鼠1周,检测血Cr与BNU、肾组织NO与ET水平、肾组织形态学,考察其肾保护作用。结果发现蕨菜乙醇提取物可显著降低小鼠血清尿酸水平,对小鼠血及肝脏黄嘌呤氧化酶活性无显著影响,显著降低血Cr、血BNU、肾组织ET水平,升高肾组织NO水平,肾组织形态学正常。结果表明蕨菜乙醇提取物具有降尿酸及肾保护作用,其降尿酸作用机制不在影响黄嘌呤氧化酶活性,确切的作用机制还有待于进一步研究。     

蕨菜乙醇提取物降尿酸作用机理及肾保护作用研究

为研究蕨菜乙醇提取物降尿酸作用机理及其肾保护作用,将蕨菜乙醇提取物灌胃模型小鼠1周,于给药第3 d,氧嗪酸钾灌胃复制高尿酸血症小鼠模型,检测血清尿酸水平、血及肝脏黄嘌呤氧化酶活性,探讨其治疗高尿酸血症作用机理;蕨菜乙醇提取物灌胃模型小鼠1周,检测血Cr与BNU、肾组织NO与ET水平、肾组织形态学,考察其肾保护作用。结果发现蕨菜乙醇提取物可显著降低小鼠血清尿酸水平,对小鼠血及肝脏黄嘌呤氧化酶活性无显著影响,显著降低血Cr、血BNU、肾组织ET水平,升高肾组织NO水平,肾组织形态学正常。结果表明蕨菜乙醇提取物具有降尿酸及肾保护作用,其降尿酸作用机制不在影响黄嘌呤氧化酶活性,确切的作用机制还有待于进一步研究。     

西藏芫根提取物对小鼠抗缺氧作用的初步研究

实验研究西藏芫根提取物的抗缺氧活性.通过建立小鼠常压缺氧模型、急性脑缺血性缺氧模型以及亚硝酸钠中毒模型,以蒸馏水作为空白对照,盐酸普萘洛尔作为阳性对照,观察芫根水、65%乙醇及95%乙醇提取物的10 g/kg、15 g/kg和20 g/kg剂量组对小鼠缺氧的保护作用,同时观察各提取物10 g/kg剂量组对红细胞数量和血红蛋白含量的影响.结果表明,芫根水提取物、65%乙醇提取物及95%乙醇提取物均能明显延长模型小鼠在常压缺氧、急性脑缺血性缺氧及亚硝酸钠中毒时的存活时间,并可增加外周血象中红细胞数与血红蛋白含量,显示芫根提取物具有抗缺氧活性.     

白花蛇舌草醇提取物对乳腺癌T-47D细胞株生长的抑制作用

目的：观察白花蛇舌草醇提取物对乳腺癌细胞T-47D生长的影响。方法：采用平皿克隆形成实验、软琼脂集落形成实验和BrdUrd（溴脱氧尿苷）掺入实验,观察不同浓度的白花蛇舌草醇提取物（1.0μg/mL,3.0μg/mL,10μg/mL,30μg/mL,100μg/mL）对T-47D细胞锚定依赖性生长和软琼脂集落形成能力及核酸合成的抑制作用。结果：①随着白花蛇舌草醇提取物浓度的升高,对T-47D细胞的生长呈现明显抑制作用;②白花蛇舌草醇提取物可呈浓度依赖性抑制对数生长期T-47D细胞核酸合成。结论：白花蛇舌草醇提取物可能通过影响肿瘤细胞核酸合成而抑制T-47D细胞生长。     

蓝莓提取物对H2O2诱导的体外培养的大鼠海马神经元氧化损伤的保护作用

目的：探讨蓝莓提取物对过氧化氢致大鼠海马神经元氧化应激损伤的减缓作用。方法：将培养7d的海马神经细胞分为8组：①过氧化氢组（H2O2）：培养液中加入50μmol/L的H2O2,作用24h。②不同剂量蓝莓提取物预处理组（BE＋H2O2）：在加入H2O2前24h,分别加入0.01、0.1、1.0、10.0、20.0和40.0μg/mlBE。③空白对照组（Control）：处理步骤同上组,但每次处理物质均为等量的培养液。通过测定细胞存活率和上清液中乳酸脱氢酶（LDH）的活性确定减轻海马神经元损伤的蓝莓提取物的适宜浓度。并检测细胞内丙二醛（MDA）含量、超氧化物歧化酶（SOD）活性以及细胞凋亡率的变化。结果：①蓝莓提取物组（0.1,1.0和10.0μg/mlBE）LDH活性显著低于H2O2组,细胞存活率由H2O2组的57.44%分别上升至78.42%、87.71%、72.40%;1μg/ml蓝莓提取物组对H2O2诱导的海马神经细胞氧化应激损伤的保护作用最好。②1μg/ml蓝莓提取物组海马神经细胞培养上清液中MDA含量及细胞凋亡率显著低于H2O2组,SOD活性显著高于H2O2组。结论：适宜剂量的蓝莓提取物对氧化应激损伤的海马神经元有一定的保护作用,其机制可能与抑制海马神经元凋亡、增强神经细胞的抗氧化功能有关。     

滇重楼茎叶总皂苷抗肝癌HepG2细胞活性

探究滇重楼茎叶总皂苷对肝癌HepG2细胞增殖的抑制、细胞周期阻滞及诱导细胞凋亡作用。从滇重楼地上茎叶提取总皂苷,配制成浓度为10μg/m L、20μg/m L、40μg/m L、80μg/m L和160μg/m L的总皂苷提取物处理HepG2细胞。总皂苷提取物对细胞增殖的抑制作用采用MTT法检测;对细胞周期阻滞作用采用流式细胞术检测;诱导细胞凋亡的作用采用细胞核荧光染色、流式细胞术和caspase-3活性试剂盒检测。结果表明,滇重楼茎叶总皂苷提取物能显著抑制细胞增殖,且具有时间、剂量依赖效应,能阻滞细胞周期于S期,并能诱导细胞凋亡。但其诱导凋亡作用仅高剂量组(≥80μg/m L)效果显著,低剂量组(80μg/m L)不显著。     

蕨菜黄酮苷元的组成及含量测定研究

以80%乙醇浸提经乙醚脱脂预处理的干蕨菜粉,减压回收乙醇得浓缩液.浓缩液以8%硫酸沸水浴水解3 h后,加入20%NaOH中和至弱酸性,过滤,滤渣以三氯甲烷索氏提取获总蕨菜黄酮苷元.TLC法检测总黄酮苷元的组成,HPLC法测定其主要苷元的含量.结果表明,通过酸水解获得总蕨菜黄酮苷元,其主要成分为山奈酚,含量约占蕨菜干重的1.9%.     

蕨菜黄酮分离鉴定

采用75%的乙醇提取经乙醚脱脂的蕨菜粉末,提取液回收乙醇后以石油醚、氯仿、乙酸乙酯、正丁醇依次萃取粗分段,硅胶柱层析、乙酸乙酯-甲醇系统对乙酸乙酯部位梯度洗脱,对其乙酸乙酯洗脱部分反复凝胶柱层析获得2个黄酮单体,分别鉴定为紫云英苷(1)、芦丁(2),其中化合物1为首次从蕨菜中分离得到。     

响应面设计法优化蕨渣基质的灵芝培养条件

探索灵芝在以蕨渣为主要成分的固态基质中的培养条件,可为蕨渣的开发利用提供理论依据。以蕨渣为主要原料,采用响应面法对灵芝培养条件（基质蕨渣比例、基质含水量和培养温度）进行优化。结果表明,基质蕨渣比例、基质含水量和培养温度对灵芝菌丝日平均生长速率均有极显著的影响（p<0.01）,且基质含水量与培养温度之间、基质蕨渣比例与基质含水量之间存在交互作用。优化出灵芝培养条件为蕨渣比例85%,基质含水量62.5%,培养温度27℃,在此条件下,灵芝菌丝日平均生长速率为3.48mm/d。多元回归分析结果显示,基质蕨渣比例、基质含水量、培养温度与菌丝日平均生长速率之间回归模型高度显著,可用于实际生产预测。首次报道了利用蕨渣培养灵芝,为蕨渣进一步的开发研究奠定基础。     

A re-evaluation of plants referred to as Pteridiutn herediae (Colmeiro) Love & Kjellqvist

SHEFFIELD, E., WOLF, P. G., HAUFLER, C. H., RANKER, T. A. & JERMY, A. C, 1989. Are-evaluation of plants referred to as Pteridiutn herediae (Colmeiro) Love & Kjellqvist. Based on perceived differences in morphology, chromosome number and habitat, specimens of Pteridiutn from southern Spain have been segregated by previous authors as a species distinct from Pteridium aquilinum , and called Pteridium herediae. However, type specimens of this taxon cannot be found. New collections of Pteridium from similar habitats in the area were examined and analysed in the present study and the results compared with those from British plants (P. aquilinum). The Spanish plants were not found to differ significantly from P. aquilinum morphologically, and all yielded chromosome counts (sporophytes, 104; gametophytes, 52) considered typical for the genus. Genotype frequency data obtained from isozyme electrophoresis of Spanish and British Pteridium yielded a genetic identity of 0.86; well within intraspecific distances found in other ferns.
These data indicate that there are currently no grounds for accepting that a form of Pteridium , distinguishable from P. aquilinum on the basis of differences in morphology, chromosome number, habitat or biochemistry, exists on the limestone soils of the Sierra de Cazorla region of southern Spain.     

An illusion of hormesis in the Ames test: statistical significance is not equivalent to biological significance

A recent report (Calabrese et al., Mutat. Res. 726 (2011) 91-97) concluded that an analysis of Ames test mutagenicity data provides evidence of hormesis in mutagenicity dose-response relationships. An examination of the data used in this study and the conclusions regarding hormesis reveal a number of concerns regarding the analyses and possible misinterpretations of the Salmonella data. The claim of hormesis is based on test data from the National Toxicology Program using Salmonella strain TA100. Approximately half of the chemicals regarded as hormetic, and the majority of the specific dose-responses identified as hormetic, were actually nonmutagenic. We conclude that the data provide no evidence of hormetic effects. The Ames test is an excellent measure of bacterial mutagenicity, but the numbers of revertant (mutant) colonies on the plate are the result of a complex interaction between mutagenicity and toxicity, which renders the test inappropriate for demonstrating hormesis in bacterial mutagenicity experiments.     

Potent suppressive effect of green tea polyphenols on tobacco-induced mutagenicity

Antimutagenic activity of green tea (Camellia sinensis) was studied using Salmonella typhimurium strains (TA 102) (Ames test). Aqueous tobacco extract was found to be mutagenic to S. typhimurium TA 102 at concentration of 50 mg/plate. Green tea polyphenols was found to inhibit the mutagenicity of tobacco in a concentration-dependent manner. Concentrations needed for 50% inhibition of mutagen-induced revertant formation was found to be 5 mg/plate. Green tea polyphenols was also found to inhibit the urinary mutagenicity in rats induced by tobacco extract. Moreover green tea polyphenols were found to inhibit in vitro nitrosation reaction produced by reaction sodium nitrite and methyl urea and further inhibition of mutagenicity indicating that green tea has dual action to bring out a reduction in the mutagenic and carcinogenic potential of tobacco.     

Global chloroplast phylogeny and biogeography of bracken (Pteridium; Dennstaedtiaceae)

Bracken ferns (genus Pteridium) represent an ancient species complex with a natural worldwide distribution. Pteridium has historically been treated as comprising a single species, but recent treatments have recognized several related species. Phenotypic plasticity, geographically structured morphological variation, and geographically biased sampling have all contributed to taxonomic confusion in the genus. We sampled bracken specimens worldwide and used variable regions of the chloroplast genome to investigate phylogeography and reticulate evolution within the genus. Our results distinguish two major clades within Pteridium, a primarily northern hemisphere Laurasian/African clade, which includes all taxa currently assigned to P. aquilinum, and a primarily southern hemisphere Austral/South American clade, which includes P. esculentum and P. arachnoideum. All European accessions of P. aquilinum subsp. aquilinum appear in a monophyletic group and are nested within a clade containing the African P. aquilinum taxa (P. aquilinum subsp. capense and P. aquilinum subsp. centrali-africanum). Our results allow us to hypothesize the maternal progenitors of two allotetraploid bracken species, P. caudatum and P. semihastatum. We also discuss the biogeography of bracken in the context of the chloroplast phylogeny. Our study is one of the first to take a worldwide perspective in addressing variation in a broadly distributed species complex.     

Genetic endemism of Galapagos Pteridium

Hybridization experiments indicate that Pteridium aquilinum from Hawaii and P. aquilinum from the Galapagos Isles are intersterile. Both of these populations will cross readily with other New World collections of Pteridium. Evidence suggests that the Galapagos populations are genetically distinct from the South American populations. The genetic divergence of the Galapagos populations has not been accompanied by morphological divergence.     

Seasonal changes in the response of wood-ants (Formica lugubris) to sucrose baits

Abstract. 1. The acceptability of sucrose solutions to Formica lugubris Zett. in the field was tested by offering droplets of known concentrations to ants tending aphids.
2. A probit model fitted to the data allowed the computation of the Median Effective Concentration (ED₅₀) and its confidence limits.
3. In spring and early summer ED₅₀ was about 0.15 M sucrose, but the ED₅₀ rose in 1 week at the end of June from 0.2 M to 0.9 M. The change was simultaneous on pine and birch trees. The ED₅₀ fell gradually to about 0.4 M in early November.
4. The increase in ED₅₀ is related to the production of the summer apterae in the aphids tended, Cinara pini (L.) on pines and Symydobius oblongus (von Heyden) on birch. This increases the 'quality' of food resource so that low sucrose concentrations can no longer compete for ant attendance.
5. The increase in ED₅₀ may limit the attendance of wood-ants at the nectaries of bracken, Pteridium aquilinum (L.) Kuhn. and at colonies of some other aphid species which are attended only in early summer.