In vitro genotoxicity of extracellular extract from Nostoc piscinale

The extracellular extract obtained from 3 weeks incubation of the soil isolate cyanobacterium strain Nostoc piscinale GT-319 in BG-11 broth medium showed cytotoxic activity against Chinese Hamster Ovary (CHO) cells. Based on comet assay, a concentration of 333 µg mL^?1 (IC₅₀) produced DNA breakages in CHO cells. The concentration of 481 mg kg^?1 (LD₅₀) produced acute toxicity in mice at 48 h.     

In vitro evaluation of human liver cancer cells and the potential cytotoxicity of Tecoma stans (Bignoniaceae) and Brickellia cavanillesi (Asteraceae) both single and in combination

Medicinal herbs are steadily increasing in complementary use for chronic and alterative therapies. The health risks associated with herbal supplements have therefore been identified as a top research priority. Tecoma stans (Tronadora), a Bignoniaceae plant, is a herbal drug traditionally consumed as tea in South America for the control of diabetes. It contains the alkaloids of tecomine and tecostanine which were shown as functional compounds responsible for hypoglycemic activity. However, the side effects of aqueous extracts of this herbal tea have not been reported. In this study, studies sought to evaluate the cytotoxicity of water extracts from T. stans in human hepatoblastoma (HepG2). Toxic effects of T. stans were concentration- and time-dependent in the presence and absence of fetal bovine serum (FBS). Cells were incubated for up to 72-h with varying concentrations of herbal extracts (60–100%), cytotoxicity was determined spectrophotometrically by MTT and reported in terms of % cell viability. For IC₅₀ assay (24 h exposure), cytotoxicity was found at concentration of 60–100%. Evaluation of the effects of T. stans and Brickellia cavanillesi (Asteraceae) in combination revealed that extracts of both herbal extracts' nontoxic levels of T. stans significantly reduced cell viability in a time-dependent manner. Further studies are needed regarding the identification, toxicity, and molecular mechanism of action of active compounds, as well as their cytotoxicity to other cell lines following exposure to both single and combined herbal extracts of these plants with anti-diabetic properties.     

Aryl hydrocarbon receptor activities of hydroxylated polycyclic aromatic hydrocarbons in recombinant yeast cells

Hydroxylated polycyclic aromatic hydrocarbons (OH-PAH) with less than four rings are frequently found in the environment, whereas the toxicities associated with these compounds remain unclear. In this study, aryl hydrocarbon receptor (AhR)–ligand binding activities of OH-PAH were investigated by using a recombinant yeast assay system. The majority of the OH-PAH tested showed AhR–ligand binding activities, especially, when the hydroxylated derivatives of naphthalene were incubated with recombinant yeast. The structure–activity relationship between AhR activity and molecular weight or the octanol–water partition coefficient value of OH-PAH displayed significant correlations. These findings indicate that the site and number of hydroxy-groups substituted on PAH skeleton apparently influenced the AhR – ligand binding activity in the recombinant yeast assay.     

苯并（a）芘对罗非鱼（GIFT Oreochromis niloticus）肝细胞DNA损伤的影响

苯并（a）芘（Benzo（a）pyrene,BaP）是一种含有5个苯环的多环芳烃,是环境中广泛存在的一类有机污染物,苯并（a）芘可引起多种形式的DNA损伤。彗星试验,又称为单细胞凝胶电泳（Single Cell Gel Electrophoresis,SCGE）,是一项灵敏、快速的在单细胞水平检测DNA链断裂的技术,已经广泛应用于水环境的生物监测中。污染物的毒性监测与评估一直是环境科学研究的热点问题之一。本文通过生态毒理学试验,利用单细胞凝胶电泳技术,研究不同浓度苯并（a）芘暴露对罗非鱼（GIFT Oreochromis niloticus）肝细胞DNA的损伤情况。试验将罗非鱼在0.1、1、10、50μg·L-14个苯并（a）芘（BaP）浓度下分别暴露4、7、14 d,利用彗星试验研究BaP对罗非鱼肝细胞DNA的损伤情况,以尾部DNA含量、尾长、尾矩及Olive尾矩为评价指标,结果表明,BaP会对肝细胞DNA造成不同程度的损伤：在0.1、1、10μg·L-13个浓度组,DNA损伤随着BaP暴露浓度的增加而增加,呈现一定的剂量效应关系,50μg·L-1组DNA损伤有所下降。在时间上,除1μg·L-1剂量组的尾部DNA含量、10μg·L-1组的尾部DNA含量及Olive尾矩外,其他指标有在第7天降低之后又升高的趋势,这意味着肝细胞DNA损伤可在一定程度上反映水体中BaP的污染情况。该实验为进一步探讨苯并（a）芘的致癌机制及环境中苯并（a）芘的监测提供一定的科学依据。     

燃煤细颗粒物对血管内皮细胞EA.hy926的细胞毒性

以银川散煤为样品煤,在实验室采用固定源稀释通道采集燃煤PM2.5,超声波水浴提取燃煤PM2.5全颗粒悬液,对人脐静脉内皮细胞EA.hy926进行染毒,并采用MTS法检测燃煤PM2.5在不同染毒时间对EA.hy926细胞增殖的影响.结果表明,燃煤PM2.5悬液对EA.hy926细胞分别染毒6,12,24h均可抑制细胞增殖,且12,24h各剂量组和溶剂对照相比具有统计学意义;在相同染毒剂量组内,和6,12h相比,染毒24h对细胞存活率抑制更加明显,其差异具有统计学意义.可见,燃煤PM2.5可以抑制血管内皮细胞增殖且具有时间和剂量依赖性,血管内皮损伤是PM2.5致心血管毒性的可能机制之一.     

Immunotoxic effect of arsenic trioxide on Caenorhabditis elegans

A Pseudomonas aeruginosa–Caenorhabditis elegans pathogenesis model was utilized to assess immunotoxic effects of arsenic trioxide (As₂O₃). After 2 h of As₂O₃ exposure, 500 µmol L^?1 and 1 mmol L^?1 As₂O₃ treatment significantly decreased median survivals of C. elegans (10 h after L4/adult molt). However, 2 h of As₂O₃ exposure caused no significant changes in the survivals rates of C. elegans (2 h after L4/adult molt). Notably, a significant dose-related immunoenhancement was observed in C. elegans (2 h after L4/adult molt) after 12 h of arsenite exposure.     

盐酸小檗碱对小鼠脾细胞的DNA损伤和氧化性损伤

为了探讨盐酸小檗碱对小鼠的DNA损伤和氧化性损伤.随机选取30只小鼠分成对照组以及7.5,15,30,60与120mg· kg-1实验组,处理后,应用小鼠脾细胞进行彗星实验与抗氧化酶实验.测定DNA损伤情况以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性以及丙二醛(MDA)含量变化.对盐酸小檗碱的DNA损伤与氧化性损伤作用进行比较研究.研究结果表明:彗星实验中,随着盐酸小檗碱浓度的增加,尾部DNA含量、尾长与尾矩均增加,与阴性对照组相比差异有统计学意义(p ＜0.05或p＜0.01),且呈剂量-效应关系;超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性随盐酸小檗碱剂量增加逐渐降低,丙二醛(MDA)含量明显上升,过氧化物酶(POD)活性在7.5 mg·kg-1时上升,而后逐渐下降.在60 mg·kg-1和120 mg· kg-1时,有极显著性差异(p＜0.01)产生.由此可见,盐酸小檗碱对小鼠脾细胞有一定的损伤作用,能够引起小鼠脾细胞的DNA损伤和氧化性损伤.     

Effect of heavy metals and PAH on soil assessed via dehydrogenase assay

Dehydrogenase enzyme activity (DHA) assay method using resazurin was accommodated for measuring of toxicity of compound contaminants on uncharacterized microbial communities present in any given soil. The method was used to compare the toxic effect of heavy metal and polycyclic aromatic hydrocarbon (PAH) contaminant mixture (Cr, Pb, Cu, Cd, Pyrene) on four typical Estonian soils covering a range of compositions. The method proved to be useable on all soils; the sensitivity of soil microbiology to toxic effect of contaminants was found to have a negative correlation with Ca and organic matter (OM) content and a positive correlation with amorphous phase content of soils.     

Comparing the Growth Characteristics of Three Bacteria Involved in Degrading Rubbers

Three bacteria isolated for degradation of rubbers were compared for their growth characteristics derived from the Bradford protein assay and turbidity (optical density, OD) measurement. Both Alcaligenes xylosoxidans T2 and Pseudomonas aeruginosa GP10 were fast-growing bacteria while Nocardia corynebacterioides S3 was a slow grower utilizing rubber as the sole source of carbon and energy, but the extent of degradation was lower by the formers than the latter. A. xylosoxidans T2, P. aeruginosa GP10 and N. corynebacterioides S3 showed a typical sigmoidal growth pattern based on binding of Coomassie Brilliant Blue G250 to bacterial proteins and spectrophotometrical measurement at 600 nm. Both assays showed similar growth characteristics for all three bacteria in this study. Degradation of rubber was more pronounced by N. corynebacterioides S3 than either A. xylosoxidans T2 or P. aeruginosa GP10 during 70 days of incubation. Our results suggest that slow-growing bacteria may play a much greater role in degrading polymeric materials than was previously believed.     

郑州大气PM10的形貌特征及生物活性研究

采集郑州市区和郊区秋季大气PM₁₀样品,利用场发射扫描电镜（FESEM）和图像分析技术对PM₁₀颗粒进行形貌特征和粒度分布进行分析,同时应用质粒DNA评价法研究了市区和郊区PM₁₀样品的生物活性.结果显示,在市区采集的样品中燃煤飞灰占有相当大的数量,而在郊区采集的样品中矿物质占有较大的数量,粒径分析表明,市区PM₁₀的数量-等效球直径分布较为集中,主要分布在0.1～0.4 μm范围内,郊区则相对比较分散;PM₁₀的体积-等效球直径主要分布在>1 μm范围内.结果表明,在郑州市秋季大气PM₁₀中,数量上细粒子占优势, 而在体积上(质量上)较粗颗粒占优势.质粒DNA评价结果表明,郑州市区和郊区PM₁₀颗粒对DNA的损伤程度不同,市区样品的生物活性大于郊区样品.