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Sample records for root tip micronucleus

  1. Vicia faba root tip micronucleus test on the mutagenicity of water-soluble contents of cigarette smoke.

    Science.gov (United States)

    Ji, Q; Chen, Y

    1996-01-16

    The possible mutagenicity of the water-soluble contents of cigarette smoke (WSCS) was evaluated by using the Vicia faba root tip micronucleus test. The results showed significant changes in micronucleus frequency which were caused by each different concentration of WSCS. This indicates that the Vicia faba root tip micronucleus test might be used as one kind of mutagenic detection method for cigarette smoke. A comparative evaluation on the mutagenicity of 10 brands of cigarettes was carried out. Results confirmed that various degrees of mutagenicity were found for all of the brand cigarettes, among them, Huaihai was the highest, while Camellia was the lowest. The micronucleus frequencies were reduced by adding tea polyphenol, nicotinamide adenine, vitamin C and sodium selenite to the WSCS. The results suggest that these added substances might reduce the genetic injury induced by cigarette smoke.

  2. Assessment of arsenic toxicity using Allium/Vicia root tip micronucleus assays.

    Science.gov (United States)

    Wu, Lihua; Yi, Huilan; Yi, Min

    2010-04-15

    Arsenic is ubiquitous in the environment and is a potential human carcinogen. Its carcinogenicity has been demonstrated in several models. In this study, broad bean (Vicia faba L.) and common onion (Allium cepa L.), two plant species which are commonly used for detecting the genotoxic effects of environmental pollutants, were used to measure possible genotoxic effect of arsenite (0.3-30 mg/l). Present results showed that arsenite (As(III)) induced micronuclei (MN) formation in both Allium and Vicia root tips. MN frequency significantly increased in Vicia root cells exposed to 0.3-10 mg/l arsenite and in Allium root cells exposed to 1-30 mg/l arsenite, which indicated that Vicia root tip cells are more sensitive to arsenite than Allium. Mitotic index (MI) decreased in a concentration-dependent manner and showed significant differences in Vicia/Allium roots among treatments and the control, after exposure to 1-30 mg/l arsenite for at least 4 h. In the present study, MN frequency was positively associated with lipid peroxidation, which indicated that arsenite exposure can induce oxidative stress, cytotoxicity and genotoxicity in plant cells. The results also suggested that Vicia/Allium root micronucleus (MN) assays are simple, efficient and reproducible methods for the genotoxicity monitoring of arsenic water contamination.

  3. [Influence of Four Kinds of PPCPs on Micronucleus Rate of the Root-Tip Cells of Vicia-faba and Garlic].

    Science.gov (United States)

    Wang, Lan-jun; Wang, Jin-hua; Zhu, Lu-sheng; Wang, Jun; Zhao, Xiang

    2016-04-15

    In order to determine the degree of biological genetic injury induced by PPCPs, the genotoxic effects of the doxycycline (DOX), ciprofloxacin (CIP), triclocarban (TCC) and carbamazepine (CBZ) in the concentration range of 12.5-100 mg · L⁻¹ were studied using micronucleus rate and micronucleus index of Vicia-fabe and garlic. The results showed that: (1) When the Vicia-faba root- tip cells were exposed to DOX, CIP, TCC and CBZ, micronucleus rates were higher than 1.67 ‰ (CK₁), it was significantly different from that of the control group (P garlic root tip cells were exposed to DOX, CIP, TCC and CBZ respectively, the micronucleus rates were less than those of the Vicia-faba, while in most treatments significantly higher than that of the control group (0.67‰). The micronucleus index was higher than 3.5 in the groups exposed to CIP with concentrations of 25, 50, 100 mg · L⁻¹ and TCC and CBZ with concentrations of 25 mg · L⁻¹; With the increase of exposure concentrations, the micronucleus rate showed a trend of first increasing and then decreasing as well. (3) Under the same experimental conditions, the cells micronucleus rates of the garlic cells caused by the four tested compounds were significantly lower than those of Vicia-faba. (4) The micronucleus index of the root tip cells of Vicia-faba and garlic treated with the four kinds of compounds followed the order of CIP > CBZ > TCC > DOX. These results demonstrated that the four compounds caused biological genetic injury to root-tip cells of Vicia-faba and garlic, and the genetic damage caused to garlic was significantly lower than that to Vicia-faba. The damages caused by the four kinds of different compounds were also different.

  4. Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay.

    Science.gov (United States)

    Song, Y F; Gong, P; Wilke, B M; Zhang, W; Song, X Y; Sun, T H; Ackland, M L

    2007-02-01

    Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.

  5. Study on Micronucleus Rates of Vicia Faba Root Tips Induced by TMV Solution%TMV溶液诱导蚕豆根尖微核的研究

    Institute of Scientific and Technical Information of China (English)

    刘开全; 马学萍; 宋路平; 李波

    2013-01-01

    In order to preliminary studying on effect of TMV solution to environmental deterioration,Micronucleus tests were conducted in Vicia faba root tips treated with different concentrations of TMV solution in the study.The results as follows:TMV solution had some inductive effect on micronucleus of Vicia faba root tips.Compared with the control group,the difference was very significant between different concentration of TMV solution and micronucleus rate of Vicia faba root tips (P=0.003<0.01).Its micronucleus rate tended to increase with the increasing of TMV solution concentration (r=0.982).Comparing with the control group,the difference was not significant(P>0.01,r=0.312) between different processing time and micronucleus rate of Vicia faba root tips treated by the same concentration of TMV solution.It is suggested that micronucleus test can be applied to monitor inherent toxicity of tobacco mosaic virus.%应用蚕豆根尖微核试验初步研究了一定浓度的烟草花叶病毒(Tobacco Mosaic Virus,TMV)溶液对环境污染的效应.结果表明,TMV溶液浓度与各处理蚕豆根尖微核率的相关性较强(r=0.982),且差异极显著(P=0.003<0.01),即蚕豆根尖微核率随着TMV溶液浓度的升高而增加;同一浓度的TMV溶液处理蚕豆根尖不同时间后其微核率在各组间没有显著差异(P>0.01),且蚕豆根尖微核率与处理时间相关性不强(r=0.312).研究表明蚕豆根尖细胞微核技术可应用于烟草花叶病毒遗传毒性监测.

  6. 苦藠对蚕豆根尖微核率的影响研究%Effect of Scallion on Micronucleus Frequency in Vicia Faba Root Tips

    Institute of Scientific and Technical Information of China (English)

    王海燕; 李睿

    2011-01-01

    Objective: To investigate the mutation of Scallion and compare the effect of different polar Scallion extract on micronucleus rate. Methods: Micronucleus tests were conducted in Vicia faba root tips treated with different concentrations of Scallion extract .Results: Different concentrations of Scallion water extract and ethanol extract treated in Viciafaba root tips. Comparing with the control group, the difference was not significant (P>0.05), and micronucleus index<1.5. So Scallion water extract and ethanol extract had no mutagenic effect. Scallion water extract had more inhibitory effect on micronucleus rate Compared with ethanol extract. The concentrations of scalli water extract between 0.008 g/ml and 0.08g/ml had micronucleus index in the range between 0.76-0.95 (mean <1.0), and reduced with the increasing of the concentration.The ethanol extract on micronucleus was no significant effect. Its micronucleus index 1.09-1.28 (<1.5) tended to decrease with increasing concentration.%目的:探讨苦藠在致突变性方面的作用,并比较不同极性苦藠提取液对蚕豆根尖微核率的影响作用.方法:蚕豆根尖细胞微核实验.结果:通过将不同浓度的苦藠水提取液和乙醇提取液处理蚕豆根尖细胞,与空白对照组比较,差别无显著性(P>0.05),且微核指数均<1.5,即苦蹔无任何致突变作用;苦藠水提取液比较乙醇提取液对蚕豆根尖微核率有一定抑制作用,其浓度在0.008g/mL-0.08g/mL之间微核指数范围在0.76-0.95(均<1.0),随浓度增加而降低,乙醇提取液对蚕豆根尖微核率无显著影响,微核指数在1.09-1.28(<1.5),随着浓度增加有降低趋势.

  7. 蚕豆根尖细胞微核技术监测湛河水质状况%Monitoring the Water Qualitv of Zhanhe River bv Micronucleus Technique of Root Tip Cell of Broad Bean

    Institute of Scientific and Technical Information of China (English)

    佘秋生; 郭端强; 田勋; 张亚杰; 郭文龙

    2011-01-01

    The water pollution of Zhanhe river was monitored by micronucleus technique of root tip cell of broad bean and the micronucleus permillage and pollution index of root tip cell of broad bean in water samples from various sampling sites were determined for F test. The results showed that the polluted degree of water body in Zhanhe river got some increment in Mar, ~ May ,the pollution state of water body in beach area was aggravated gradually and the control of water quality needed to be enhanced.%利用蚕豆根尖细胞微核技术监测湛河水质污染状况,测定各样点水样中蚕豆根尖细胞的微核千分率及污染指数,并进行F检验.结果表明,3~5月湛河水体受污染程度有所增加,沿岸水体污染状况逐渐加重,需加强水质治理工作.

  8. Genotoxicity and mutagenicity of water contaminated with tannery effluents, as evaluated by the micronucleus test and comet assay using the fish Oreochromis niloticus and chromosome aberrations in onion root-tips

    Directory of Open Access Journals (Sweden)

    Silvia Tamie Matsumoto

    2006-01-01

    Full Text Available Cytotoxicity of metals is important because some metals are potential mutagens able to induce tumors in humans and experimental animals. Chromium can damage DNA in several ways, including DNA double strand breaks (DSBs which generate chromosomal aberrations, micronucleus formation, sister chromatid exchange, formation of DNA adducts and alterations in DNA replication and transcription. In our study, water samples from three sites in the Córrego dos Bagres stream in the Franca municipality of the Brazilian state of São Paulo were subjected to the comet assay and micronucleus test using erythrocytes from the fish Oreochromis niloticus. Nuclear abnormalities of the erythrocytes included blebbed, notched and lobed nuclei, probably due to genotoxic chromium compounds. The greatest comet assay damage occurred with water from a chromium-containing tannery effluent discharge site, supporting the hypothesis that chromium residues can be genotoxic. The mutagenicity of the water samples was assessed using the onion root-tip cell assay, the most frequent chromosomal abnormalities observed being: c-metaphases, stick chromosome, chromosome breaks and losses, bridged anaphases, multipolar anaphases, and micronucleated and binucleated cells. Onion root-tip cell mutagenicity was highest for water samples containing the highest levels of chromium.

  9. 不同污水对蚕豆根尖微核诱导率的影响%Effects of Different Sewages on Micronucleus Induction Rates of Vicia faba Root Tip cells

    Institute of Scientific and Technical Information of China (English)

    余代龙; 杨先泉; 谭利; 蒋琴

    2011-01-01

    [目的]探讨不同工业污水对环境的污染程度.[方法]采用蚕豆根尖微核技术,测定了雅安2种类型工业污水对蚕豆根尖细胞微核的遗传毒性.[结果]铸造厂污水和制药厂污水诱发的蚕豆根尖微核细胞率分别为21.65‰和23.55‰.卡方分析结果显示,2种污水样品诱发的微核细胞率与阴性对照间差异极显著.[结论]不同类型的工业污水对蚕豆根尖细胞微核的诱导程度有差异,蚕豆根尖细胞微核对各种工业污水的遗传毒性十分敏感.%[Objective] The aim was to explore pollution degrees of different industrial sewages on environment. [ Method] The genotoxicity of 2 kinds of industrial sewages from Ya' an on root tip cells of Viciafaba were tested by micronucleus assay. [ Result] Micronucleus frequencies induced by the sewages from a pharmaceutical industry and a plating factory in Ya' an were 21.65%. And 23.55%., respectively. There were significant differences between the two treated groups and negative control (P<0.01). [Conclusion] The micronucleus frequencies induced by different industrial sewages are different The micronuclens of Vicia faba root tip cells are very sensitive to the genotoxicity of various sewages.

  10. 除草剂对蚕豆根尖微核细胞率的影响%The Micronucleus Rate of Root Tip Cells of Vicia faba Induced by Herbicides

    Institute of Scientific and Technical Information of China (English)

    高惠仙; 张晓红

    2011-01-01

    To explore the impact of herbicides on crops, three herbicides, Paraquat, Butachlor, 2, 4-D butylate were chosen, and the micronucleus test was used to test the toxicity of root tip cells of Viciafaba induced by herbicide. The results showed that, three herbicides all induced the micronuclei effects on root tip cells of Viciafaba, and showed dose-effect relationship. The toxic of Butachlor was higher than 2, 4-D butylate and Paraquat.%为探讨除草剂对经济作物的影响,选择百草枯、丁草胺、2,4-D丁酯这3种除草剂,采用微核方法测定除草剂对蚕豆根尖细胞的毒性.结果表明,3种除草剂均不同程度引起蚕豆根尖微核细胞率的增高,且呈现明显的剂量效应关系;3种除草剂中,丁草胺毒性最高,2,4-D丁酯次之,百草枯最低.

  11. 蛹虫草胞内锌多糖对丝裂霉素诱发蚕豆根尖细胞微核的影响%Effect of intra-polysaccharide zinc-riched of Cordyceps militaris on micronucleus of Vicia faba root tip cells induced by Mitomycin-c

    Institute of Scientific and Technical Information of China (English)

    李素婷; 朱蕴兰; 张城; 陈宏伟; 宋海燕

    2011-01-01

    以蛹虫苹为材料,利用蚕豆根尖细胞微核实验,探讨了蛹虫草胞内锌多糖对丝裂霉素(MMC)诱发的蚕豆根尖细胞微核的影响。结果表明:胞内锌多糖对蚕豆根尖细胞微核的产生具有显著的抑制作用,且胞内锌多糖抑制微核产生的能力随胞内锌多糖浓度增加而增强.当胞内锌多糖浓度为100ug/mL时,抑制MMC诱发的蚕豆根尖细胞微核率最高到达59.56%。蛹虫草胞内锌多糖具有显著抑制蚕豆根尖细胞微核产生的能力。%With Cordyceps militaris as material,micronucleus of Vicia faba root tip cells was tested,discussing effects of intra-polysaccharide zinc-riched of Cordyceps militaris on micronucleus of Vicia faba root tip cells induced by Mitomycin-c. Results showed that: intra-polysaccharids zinc-riched of Cordyceps militaris inhibited the production of micronucleus of Vicia faba root tip cells significantly. And the inhibition effect of intra- polysaccharide zinc-riched of Cordyceps militaris on micronucleus of Vicia faba root tip cells was intenser as the concentration of intra-polysaccharids zinc-riched increased. When the concentration of intra-polysaccharids zinc-riched was 100ug/mL,the inhibition density of intra-polysaccharids zinc-riched on micronuclear of Vicia faba root tip cells induced by Mitomycin-c reached to the highest at 59.56%. Intra-polysaccharide zinc-riched of Cordyceps militaris had significant ability to inhibit the production of micronucleus of Vicia faba root tip cells.

  12. Joint effects of microwave and chromium trioxide on root tip cells of Vicia faba

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mutagenic effects of microwave and chromium trioxide (CrO3) on Viciafaba root tip were studied. Micronucleus assay and chromosomal aberration assay were used to determine the mitotic index, the micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells induced by microwave and CrO3. The results showed that the micronucleus frequency decreased, and that the mitotic index and chromosomal aberration frequency showed linear dose responses to CrO3, in treatment of microwave for 5 s. In microwave of 25 s, the mitotic index decreased, the micronucleus frequency and chromosomal aberration frequency increased with increase of CrO3 concentration. We concluded that microwave and CrO3 had antagonistic effect on the mitotic index of Vicia faba root tip cells, but had synergetic effect on micronucleus frequency and chromosomal aberration frequency of Vicia faba root tip cells.

  13. Mutagenic effects of chromium trioxide on root tip cells of Vicia faba

    Institute of Scientific and Technical Information of China (English)

    钱晓薇

    2004-01-01

    In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO3) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, micronucleus rate and chromosome aberration rate of Viciafaba root tip cells. The results showed that the effects of CrO3 concentration on the mitotic indexes were complicated. CrO3 increases the micronucleus rate of Vicia faba root tip cells. It was found that within certain range of CrO3 concentration the micronucleus rate increased systematically with increased concentration of CrO3, but that the micronucleus rate decreased at higher level of CrO3 and that CrO3 also caused various types of chromosome aberration at a rate which increased systematically with increased concentration of CrO3. We concluded that CrO3 has significant mutagenic effect on Viciafaba root tip cells.

  14. Mutagenic effects of chromium trioxide on root tip cells of Vicia faba

    Institute of Scientific and Technical Information of China (English)

    钱晓徽

    2004-01-01

    In this study on the mutagenic effects of different concentrations of chromium trioxide (CrO3) on Vicia faba root tip, micronucleus assay and chromosome aberration assay were used to determine the mitotic indexes, micronucleus rate and chromosome aberration rate of Vicia faba root tip cells. The results showed that the effects of CrO3 concentration on the mitotic indexes were complicated. CrO3 increases the micronucleus rate of Vicia faba root tip cells. It was found that within certain range of CrO3 concentration the micronucleus rate increased systematically with increased concentration of CrO3, but that the micronucleus rate decreased at higher level of CrO3 and that CrO3 also caused various types of chromosome aberration at a rate which increased systematically with increased concentration of CrO3. We concluded that CrO3 has significant mutagenic effect on Vicia faba root tip cells.

  15. Effects of water extract of cordyceps militaris on Cu2+induced micronucleus rate of viciafaba root-tip cells%蛹虫草水提液对Cu2+诱发蚕豆根尖微核率的影响

    Institute of Scientific and Technical Information of China (English)

    田雪莲; 陆伟东; 田雪珊; 卯霞

    2011-01-01

    通过蚕豆根尖细胞微核实验,研究蛹虫草水提液对Cu2+诱发蚕豆根尖微核的影响.结果显示,当蛹虫草提取液浓度为5mg/mL以上时,对蚕豆根尖细胞自然诱导的微核产生有显著的抑制作用,对Cu2+诱导的蚕豆根尖细胞微核亦有显著的抑制作用,抑制率均可达50%以上.结论:蛹虫草水提液可有效地抑制蚕豆根尖细胞微核的产生,且抑制作用随着蛹虫草水提液浓度的增大而增强,表明蛹虫草水提取液具有抑制Cu2+遗传毒性的作用.本实验为蛹虫草作为功能性食品开发利用提供新的应用范围.%Micronucleus test was designed to study effects of water extract of cordyceps militaris on micronucleus rate of vicia faba root-tip cells induced by Cu2+ .The results showed when the concentration of water extract of cordyceps militaris was 5mg/mL,the micronucleus formation( MCN% )in root tip cell which was created naturally or induced with Cu2+ was significant different,the inhibition rate on micronucleus formation was more than 50%.In conclusion,the water extract of corcyceps militaris can effectively inhibit the creation of root tip cells micronucleus of Vicia faba and the inhibitory action of the water extract of cordyceps militaris can be strengthened along with the increasing concentrations of itself,which indicated the water extract of cordyceps militaris had an inhibitory effect on hereditary toxicity.

  16. 4种典型PPCPs对蚕豆和大蒜根尖细胞微核率的影响%Influence of Four Kinds of PPCPs on Micronucleus Rate of the Root-Tip Cells of Vicia-faba and Garlic

    Institute of Scientific and Technical Information of China (English)

    王兰君; 王金花; 朱鲁生; 王军; 赵祥

    2016-01-01

    In order to determine the degree of biological genetic injury induced by PPCPs, the genotoxic effects of the doxycycline ( DOX) , ciprofloxacin ( CIP) , triclocarban ( TCC) and carbamazepine ( CBZ) in the concentration range of 12. 5-100 mg•L-1 were studied using micronucleus rate and micronucleus index of Vicia-faba and garlic. The results showed that:①When the Vicia-faba root-tip cells were exposed to DOX, CIP, TCC and CBZ, micronucleus rates were higher than 1. 67‰( CK1 ) , it was significantly different from that of the control group ( P﹤0. 05) , and the micronucleus index was even greater than 3. 5;With the increasing concentrations of the PPCPs, the micronucleus rates first increased and then decreased. ②When the garlic root tip cells were exposed to DOX, CIP, TCC and CBZ respectively, the micronucleus rates were less than those of the Vicia-faba, while in most treatments significantly higher than that of the control group (0. 67‰). The micronucleus index was higher than 3. 5 in the groups exposed to CIP with concentrations of 25, 50, 100 mg•L-1 and TCC and CBZ with concentrations of 25 mg•L-1; With the increase of exposure concentrations, the micronucleus rate showed a trend of first increasing and then decreasing as well. ③Under the same experimental conditions, the cells micronucleus rates of the garlic cells caused by the four tested compounds were significantly lower than those of Vicia-faba. ④ The micronucleus index of the root tip cells of Vicia-faba and garlic treated with the four kinds of compounds followed the order of CIP﹥CBZ﹥TCC﹥DOX. These results demonstrated that the four compounds caused biological genetic injury to root-tip cells of Vicia-faba and garlic, and the genetic damage caused to garlic was significantly lower than that to Vicia-faba. The damages caused by the four kinds of different compounds were also different.%药物及个人护理品( PPCPs)对生态环境的潜在风险受到世界各国科学家

  17. Extracellular DNA: the tip of root defenses?

    Science.gov (United States)

    Hawes, Martha C; Curlango-Rivera, Gilberto; Wen, Fushi; White, Gerard J; Vanetten, Hans D; Xiong, Zhongguo

    2011-06-01

    This review discusses how extracellular DNA (exDNA) might function in plant defense, and at what level(s) of innate immunity this process might operate. A new role for extracellular factors in mammalian defense has been described in a series of studies. These studies reveal that cells including neutrophils, eosinophils, and mast cells produce 'extracellular traps' (ETs) consisting of histone-linked exDNA. When pathogens are attracted to such ETs, they are trapped and killed. When the exDNA component of ETs is degraded, trapping is impaired and resistance against invasion is reduced. Conversely, mutation of microbial genes encoding exDNases that degrade exDNA results in loss of virulence. This discovery that exDNases are virulence factors opens new avenues for disease control. In plants, exDNA is required for defense of the root tip. Innate immunity-related proteins are among a group of >100 proteins secreted from the root cap and root border cell populations. Direct tests revealed that exDNA also is rapidly synthesized and exported from the root tip. When this exDNA is degraded by the endonuclease DNase 1, root tip resistance to fungal infection is lost; when the polymeric structure is degraded more slowly, by the exonuclease BAL31, loss of resistance to fungal infection is delayed accordingly. The results suggest that root border cells may function in a manner analogous to that which occurs in mammalian cells.

  18. Root tips moving through soil: an intrinsic vulnerability.

    Science.gov (United States)

    Curlango-Rivera, Gilberto; Hawes, Martha C

    2011-05-01

    Root elongation occurs by the generation of new cells from meristematic tissue within the apical 1-2 mm region of root tips. Therefore penetration of the soil environment is carried out by newly synthesized plant tissue, whose cells are inherently vulnerable to invasion by pathogens. This conundrum, on its face, would seem to reflect an intolerable risk to the successful establishment of root systems needed for plant life. Yet root tip regions housing the meristematic tissues repeatedly have been found to be free of microbial infection and colonization. Even when spore germination, chemotaxis, and/or growth of pathogens are stimulated by signals from the root tip, the underlying root tissue can escape invasion. Recent insights into the functions of root border cells, and the regulation of their production by transient exposure to external signals, may shed light on long-standing observations. 

  19. Extracellular proteins in pea root tip and border cell exudates.

    Science.gov (United States)

    Wen, Fushi; VanEtten, Hans D; Tsaprailis, George; Hawes, Martha C

    2007-02-01

    Newly generated plant tissue is inherently sensitive to infection. Yet, when pea (Pisum sativum) roots are inoculated with the pea pathogen, Nectria haematococca, most newly generated root tips remain uninfected even though most roots develop lesions just behind the tip in the region of elongation. The resistance mechanism is unknown but is correlated spatially with the presence of border cells on the cap periphery. Previously, an array of >100 extracellular proteins was found to be released while border cell separation proceeds. Here we report that protein secretion from pea root caps is induced in correlation with border cell separation. When this root cap secretome was proteolytically degraded during inoculation of pea roots with N. haematococca, the percentage of infected root tips increased from 4% +/- 3% to 100%. In control experiments, protease treatment of conidia or roots had no effect on growth and development of the fungus or the plant. A complex of >100 extracellular proteins was confirmed, by multidimensional protein identification technology, to comprise the root cap secretome. In addition to defense-related and signaling enzymes known to be present in the plant apoplast were ribosomal proteins, 14-3-3 proteins, and others typically associated with intracellular localization but recently shown to be extracellular components of microbial biofilms. We conclude that the root cap, long known to release a high molecular weight polysaccharide mucilage and thousands of living cells into the incipient rhizosphere, also secretes a complex mixture of proteins that appear to function in protection of the root tip from infection.

  20. Disproportionate abundance between ectomycorrhizal root tips and their associated mycelia

    DEFF Research Database (Denmark)

    Kjøller, Rasmus

    2006-01-01

    Extensive knowledge of various ectomycorrhizal fungal communities has been obtained over the past 10 years based on molecular identification of the fungi colonizing fine roots. In contrast, only limited information exists about the species composition of ectomycorrhizal hyphae in soil. This study...... compared the ectomycorrhizal external mycelial community with the adjacent root-tip community in a Danish beech forest. Sand-filled in-growth mesh bags were used to trap external mycelia by incubating the mesh bags in the soil for 70 days. The adjacent ectomycorrhizal root-tip communities were recorded...

  1. Microtubules guide root hair tip growth

    NARCIS (Netherlands)

    Sieberer, B.; Ketelaar, M.J.; Esseling, J.J.; Emons, A.M.C.

    2005-01-01

    The ability to establish cell polarity is crucial to form and function of an individual cell. Polarity underlies critical processes during cell development, such as cell growth, cell division, cell differentiation and cell signalling. Interphase cytoplasmic microtubules in tip-growing fission yeast

  2. Microtubules guide root hair tip growth

    NARCIS (Netherlands)

    Sieberer, B.; Ketelaar, M.J.; Esseling, J.J.; Emons, A.M.C.

    2005-01-01

    The ability to establish cell polarity is crucial to form and function of an individual cell. Polarity underlies critical processes during cell development, such as cell growth, cell division, cell differentiation and cell signalling. Interphase cytoplasmic microtubules in tip-growing fission yeast

  3. Micronucleus Test in Vicia Faba Root Tip Cell to Inspect the Water Quality of Qingyi River in Wuhu City%青弋江芜湖市段水环境质量的蚕豆根尖微核检测

    Institute of Scientific and Technical Information of China (English)

    王友保; 刘登义

    2001-01-01

    @@ 微核实验(micronucleus test,MCNT)是根据环境污染物能引起染色体畸变而形成微核的原理来测诱变物质对染色体损伤用的一种简便易行的法.陈光荣在1983年开始用蚕豆根尖微核技术(Vicia-MCN)来检测农药和化学诱变剂对染色体的损伤情况[8].1986年,国家环保局把用蚕豆根尖微核技术监测水污染的测试方法编入了[3].目前利用蚕豆初生根尖微核技术监测环境污染和危险化学品的研究已得到了广泛的用[4~7],成为我国水环境监测的规范化方法之一[8,9].本文应用该技术对青弋江芜湖市段水体的致突变性进行分析和研究.

  4. Micropropagation of Cyrtopodium paludicolum (Orchidaceae from root tip explants

    Directory of Open Access Journals (Sweden)

    Dayana Rotili Nunes Picolotto

    2017-06-01

    Full Text Available An efficient protocol for in vitro plant propagation of Cyrtopodium paludicolum has been developed using root tips dissected from well-developed seedlings. Root tips were cultured on Knudson medium supplemented with α-naphthaleneacetic acid (NAA, and/or thidiazuron (TDZ. TDZ did not induce protocorm-like bodies (PLBs in the NAA absence, indicating phytoregulators synergistic effect. Medium supplemented with 1.34 μM NAA and 2.27 μM TDZ resulted in better response on PBLs, and subsequent shoot differentiation (55.25 shoots per explant, and in better rooting number and root length responses, favoring acclimatization with 90% of survived plants. However, the medium supplemented with only NAA (1.34 μM resulted in 33.50 shoots per explant. Histological sections confirmed that only one PLB was induced per responsive root tip, and it showed numerous dispersed and extended meristemoids, or division centers that originated new PBLs. Additionally, this protocol could be an excellent model to study molecular aspects of root to shoot conversion.

  5. Study on genotoxicity effect of domestic sewage on cell of broad bean root tip%生活污水对蚕豆根尖细胞致畸效应的研究

    Institute of Scientific and Technical Information of China (English)

    李亚青; 李屹

    2013-01-01

    以蚕豆根尖为材料,采用蚕豆根尖细胞的微核试验和染色体畸变试验方法,研究不同取样点生活污水对蚕豆根尖细胞的致畸效应.结果表明:生活污水能诱发微核率升高,而且在一定范围内,其微核率随污染物浓度升高而增加,但高于一定浓度后有下降趋势;不同取样点的污水均使蚕豆根尖细胞有丝分裂指数下降;生活污水还能诱导蚕豆根尖细胞产生较高频率的染色体畸变.所以生活污水蚕豆根尖细胞具有明显的致畸效应.%The paper investigated the genotoxicity effect of domestic sewage from different treatment processes on the cell of broad bean root tip.The micronucleus and chromosome aberration assay were conducted to determine the micronucleus rate and chromosome aberration rate of broad bean root tip cells induced by domestic sewage.The result indicated that domestic sewage could increase the micronucleus rate of the sells of broad bean root tip.Within certain concentration range of pollutant,the micronucleus rate increased with the increase of the concentration of pollutants,but beyond certain range,the micronucleus rate decreased with further increase of the concentration of pollutants.Domestic sewage could decrease the cell mitosis index.Furthermore,it also caused the increase of chromosome aberration rate.The conclusion is that domestic sewage has obvious genotoxicity effect on the cell of broad bean root tip.

  6. 烟草浸提液对蚕豆根尖的遗传损伤%The Genetic Damage of Smokeless Tobacco Extract on Vicia Faba Root Tip

    Institute of Scientific and Technical Information of China (English)

    李桂芳; 吴学进; 黄先忠.; 张婷婷

    2012-01-01

    利用不同浓度的烟草浸提液对蚕豆根尖进行常温处理,结果对蚕豆根尖细胞造成不同程度的遗传损伤,而且根尖细胞微核率与烟草浸提液浓度成正相关。%Vicia faba root tip was treated using different concentrations of smokeless tobacco extract at normal temperature. Result indicated that the rc,ot tip cells of Vicia faba suffered different degree of genetic damage, and root tip cell micronucleus rate was positively ~'orrelated with the concentration of smokeless tobacco extract.

  7. H-independent glutamine transport in plant root tips.

    Directory of Open Access Journals (Sweden)

    Huaiyu Yang

    Full Text Available BACKGROUND: Glutamine is one of the primary amino acids in nitrogen assimilation and often the most abundant amino acid in plant roots. To monitor this important metabolite, a novel genetically encoded fluorescent FRET-reporter was constructed and expressed in Arabidopsis thaliana. As a candidate for the glutamine fluxes, the root tip localized, putative amino acid transporter CAT8 was analyzed and heterologously expressed in yeast and oocytes. PRINCIPAL FINDINGS: Rapid and reversible in vivo fluorescence changes were observed in reporter-expressing root tips upon exposure and removal of glutamine. FRET changes were detected at acid and neutral pH and in the presence of a protonophore, suggesting that part of the glutamine fluxes were independent of the pH. The putative amino acid transporter CAT8 transported glutamine, had a half maximal activity at approximately 100 microM and the transport was independent of external pH. CAT8 localized not only to the plasma membrane, but additionally to the tonoplast, when tagged with GFP. Ultrastructural analysis confirmed this dual localization and additionally identified CAT8 in membranes of autophagosomes. Loss-of function of CAT8 did not affect growth in various conditions, but over-expressor plants had increased sensitivity to a structural substrate analog, the glutamine synthetase inhibitor L-methionine sulfoximine. CONCLUSIONS: The combined data suggest that proton-independent glutamine facilitators exist in root tips.

  8. The possible involvement of root-cap mucilage in gravitropism and calcium movement across root tips of Allium cepa L

    Science.gov (United States)

    Moore, R.; Fondren, W. M.

    1986-01-01

    Roots of Allium cepa L. grown in aerated water elongate rapidly, but are not graviresponsive. These roots (1) possess extensive columella tissues comprised of cells containing numerous sedimented amyloplasts, (2) lack mucilage on their tips, and (3) are characterized by a weakly polar movement of calcium (Ca) across their tips. Placing roots in humid air correlates positively with the (1) onset of gravicurvature, (2) appearance of mucilage on tips of the roots, and (3) onset of the ability to transport Ca polarly to the lower side of the root tip. Gravicurvature of roots previously submerged in aerated water is more rapid when roots are oriented vertically for 1-2 h in humid air prior to being oriented horizontally. The more rapid gravicurvature of these roots correlates positively with the accumulation of mucilage at the tips of roots during the time the roots are oriented vertically. Therefore, the onset of gravicurvature and the ability of roots to transport Ca to the lower sides of their tips correlate positively with the presence of mucilage at their tips. These results suggest that mucilage may be important for the transport of Ca across root caps.

  9. The cytochemical localization of ascorbic acid in root tip cells.

    Science.gov (United States)

    JENSEN, W A; KAVALJIAN, L G

    1956-01-25

    The intracellular distribution of ascorbic acid was studied in frozen-dried root tips of Allium cepa and Vicia faba by the silver nitrate procedure. The sites of the ascorbic acid as indicated by the deposited silver appear as spherical (0.2 to 0.6 micro in diameter) cytoplasmic particles. The site appears to have small amounts of lipides and to be rich in ribonucleic acid. These particles are concluded to be submicroscopic in size and associated, in the elongating cell, with the cell surface. In the meristematic cells they appear fewer in number and are distributed throughout the cytoplasm.

  10. 空气中高浓度二氯乙烷对蚕豆根尖细胞遗传毒性研究%The genotoxicity of High-Dose Concentration in the Air on Vicia faba Root Tips Cells

    Institute of Scientific and Technical Information of China (English)

    陈洋; 周小敏; 熊旭辉; 谭广辉; 张琼

    2012-01-01

    Objective To explore the feasibility of micronucleus test of Vicia faba root-tip cell in application of mutation detection caused by air pollutants. Methods This experiment takes available Vicia faba as research objects, which was poisoned by high concentration dichloroethane of simulated indoor air at airtight container. Results With the increasing of concentration, the descending trend of mitotic index and the escalation of average micronucleus rate and chromosome aberration rate had been observed, which showed a conspicuous dose-response relationship. Conclusion Genetic toxic effects of Vicia faba root-tip cell caused by dichloroethane are unquestionable under all experiment concentration. Furthermore, it is possible that the using of micronucleus test in Vicia faba linn root-tip cell for high concentration dichloroethane of indoor air.%目的 探讨将蚕豆根尖微核检测系统(micronucleus,MCN)应用于空气污染物致突变性检测的可行性.方法 以市售蚕豆为材料,在密闭容器中模拟室内空气的高浓度二氯乙烷污染,对蚕豆进行染毒.结果 随着浓度的递增,平均微核率、染色体畸变率逐步上升,有丝分裂指数有下降趋势,表现出明显的剂量效应关系.结论 在实验浓度下,1,2-二氯乙烷有对蚕豆根尖细胞产生遗传毒害效应.应用蚕豆根尖微核技术检测室内高浓度1,2-二氯乙烷污染物是可行的.

  11. Effects of Kinetin and Root Tip Removal on Exudation and Potassium (Rubidium) Transport in Roots of Honey Locust 1

    Science.gov (United States)

    Hong, Sung Gak; Sucoff, Edward

    1976-01-01

    Exudation, 86Rb transport, and water permeability were examined in excised roots of honey locust (Gleditsia triacanthos L.) treated by removing the tip 2 mm (tip-cut 2 mm) or tip 8 mm of the root, or by adding kinetin, or by both treatments. Tip removal increased the rate of exudation. Kinetin, 5 × 10−6m, inhibited exudation and Rb transport in tip-cut 2-mm roots; the inhibition was reversible. Kinetin inhibition of exudation was initially associated with lower K(Rb) transport and later with decreases in both ion transport and water permeability. Exudation was also inhibited at 10−10 to 10−7m kinetin. Exudation from roots with intact tips was not altered by kinetin until after about 24 hours. Light during the exudation period had no significant (95%) influence on rate of exudation during the first 24 hours whether root tips were cut or kinetin applied. The results suggest the involvement of the root tip in regulating exudation in other parts of the root. This regulation might occur through cytokinin control of water permeability and the rate of ion transport. PMID:16659457

  12. Effects of kinetin and root tip removal on exudation and potassium (rubidium) transport in roots of honey locust.

    Science.gov (United States)

    Hong, S G; Sucoff, E

    1976-02-01

    Exudation, (86)Rb transport, and water permeability were examined in excised roots of honey locust (Gleditsia triacanthos L.) treated by removing the tip 2 mm (tip-cut 2 mm) or tip 8 mm of the root, or by adding kinetin, or by both treatments. Tip removal increased the rate of exudation. Kinetin, 5 x 10(-6)m, inhibited exudation and Rb transport in tip-cut 2-mm roots; the inhibition was reversible. Kinetin inhibition of exudation was initially associated with lower K(Rb) transport and later with decreases in both ion transport and water permeability. Exudation was also inhibited at 10(-10) to 10(-7)m kinetin. Exudation from roots with intact tips was not altered by kinetin until after about 24 hours. Light during the exudation period had no significant (95%) influence on rate of exudation during the first 24 hours whether root tips were cut or kinetin applied.The results suggest the involvement of the root tip in regulating exudation in other parts of the root. This regulation might occur through cytokinin control of water permeability and the rate of ion transport.

  13. Cytological reactions induced by sodium fluoride in Allium cepa root tip chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    Mohamed, A.H.; Applegate, H.G.; Smith, J.D.

    1966-06-01

    The cytological effect of an aqueous sodium fluoride solution of lx10/sup -2/M was studied on onion root tip chromosomes. Root tip smears showed that this chemical agent was able to induce anaphase bridges and fragments. Tetraploid nuclei and multipolar anaphases were also observed.

  14. Effect of detergent concentrations on root tip cells teratogenesis of pea%洗涤剂对豌豆根尖细胞的致畸效应

    Institute of Scientific and Technical Information of China (English)

    曾秀存; 许耀照; 王勤礼; 李彩霞

    2011-01-01

    the micronucleus test was used to determine the effects of detergent concentrations on root tip cells teratogenesis of pea by measuring the cytotoxicity and the genotoxicity. In this study, the dilution detergent concentrations with 200 volume (detergent/distilled water), 100 volume, 10 volume and 5 volume, respectively, was added into pea root tip and root point cell mitosis index, the micronucleus rate and chro- mosomic aberration rate were investigated and made micrography at 24 h and 48 h. The results of this study showed that the root tip cell mitosis index obvlously decreased and had the obvious dosage-time effectiveness, and the micronucleus rate and the chromosomic aberration rate increased in low concentrations, but they decreased in high concentrations and they did not have the obvious dosage-time effect along with the increase of detergent diluted concentration and with the lengthens of treatment time. The cell chromosome bridge, micronucleus and many kinds of chromosomic aberration type were caused with different concentrations detergent, and the root tip cell chromosome damage was created as well. This study suggested that the different concentrations detergent had some certain heredity toxicity to the pea root tip cell.%为研究洗涤剂对豌豆(Pisum sativum)是否产生细胞毒性和遗传毒性效应,以豌豆根尖细胞为材料,利用微核技术,用不同稀释倍数的洗涤剂对根尖处理24和48h,设4个稀释倍数分别为200倍、100倍、10倍、5倍,统计豌豆根尖细胞有丝分裂指数、微核率及染色体畸变率,并进行显微摄影。结果表明,随洗涤剂原液稀释倍数的降,低和处理时间的延长,根尖细胞有丝分裂指数明显下降,并具有明显剂量一时间效应关系;微核率和染色体畸变率先升高后下降,不具有剂量一时间效应。稀释不同倍数洗涤剂能引起根尖细胞染色体桥、微核等多种染色体畸变类型,造成根

  15. Extracellular DNA is required for root tip resistance to fungal infection.

    Science.gov (United States)

    Wen, Fushi; White, Gerard J; VanEtten, Hans D; Xiong, Zhongguo; Hawes, Martha C

    2009-10-01

    Plant defense involves a complex array of biochemical interactions, many of which occur in the extracellular environment. The apical 1- to 2-mm root tip housing apical and root cap meristems is resistant to infection by most pathogens, so growth and gravity sensing often proceed normally even when other sites on the root are invaded. The mechanism of this resistance is unknown but appears to involve a mucilaginous matrix or "slime" composed of proteins, polysaccharides, and detached living cells called "border cells." Here, we report that extracellular DNA (exDNA) is a component of root cap slime and that exDNA degradation during inoculation by a fungal pathogen results in loss of root tip resistance to infection. Most root tips (>95%) escape infection even when immersed in inoculum from the root-rotting pathogen Nectria haematococca. By contrast, 100% of inoculated root tips treated with DNase I developed necrosis. Treatment with BAL31, an exonuclease that digests DNA more slowly than DNase I, also resulted in increased root tip infection, but the onset of infection was delayed. Control root tips or fungal spores treated with nuclease alone exhibited normal morphology and growth. Pea (Pisum sativum) root tips incubated with [(32)P]dCTP during a 1-h period when no cell death occurs yielded root cap slime containing (32)P-labeled exDNA. Our results suggest that exDNA is a previously unrecognized component of plant defense, an observation that is in accordance with the recent discovery that exDNA from white blood cells plays a key role in the vertebrate immune response against microbial pathogens.

  16. Effects of geometry and tip speed ratio on the HAWT blade's root flow

    NARCIS (Netherlands)

    Akay, B.; Micallef, D.; Simao Ferreira, C.J.; Van Bussel, G.J.W.

    2014-01-01

    In this study, the effect of the parameters playing a role in the root flow behavior of HAWT are only partly understood. To better reveal the root flow properties, this study presents the progression of HAWT blade root flow at two different blade geometries and at two different tip speed ratios. The

  17. Effects of cloning and root-tip size on observations of fungal ITS sequences from Picea glauca roots.

    Science.gov (United States)

    Lindner, Daniel L; Banik, Mark T

    2009-01-01

    To better understand the effects of cloning on observations of fungal ITS sequences from Picea glauca (white spruce) roots two techniques were compared: (i) direct sequencing of fungal ITS regions from individual root tips without cloning and (ii) cloning and sequencing of fungal ITS regions from individual root tips. Effect of root tip size was investigated by selecting 20 small root tips (SRT, 1.0-2.0 mm long) and 20 large root tips (LRT, 5.0-6.0 mm long). DNA was isolated from each tip and PCR-amplified with fungal-specific primers. PCR reactions were divided into two portions, one of which was sequenced directly and one of which was cloned first followed by sequencing of 12 random clones. With direct sequencing all 20 SRT produced an identifiable sequence, while only 13 of 20 LRT (65%) yielded an identifiable sequence. With cloning and sequencing all 40 tips produced identifiable fungal ITS sequences regardless of size. Failure of direct sequencing in LRT was associated with the presence of multispecies assemblages. Cloning identified 18 taxa overall while direct sequencing identified four. Cloning was not affected by tip size and identified more taxa relative to direct sequencing, although cost and probability of observing lab-based contaminants (e.g., airborne or reagent-based) were higher. We suggest that standardized controls be run whenever clones are sequenced from environmental samples, including positive controls derived from pure cultures and negative controls that cover the entire extraction, amplification and cloning process. Additional studies on larger root segments and bulked samples are needed to determine whether cloning can detect fungi accurately and cost-effectively in complex environmental samples.

  18. Root-soil friction: quantification provides evidence for measurable benefits for manipulation of root-tip traits.

    Science.gov (United States)

    McKenzie, Blair M; Mullins, Christopher E; Tisdall, Judith M; Bengough, A Glyn

    2013-06-01

    To penetrate soil, a root requires pressure both to expand the cavity it is to occupy, σn , and to overcome root-soil friction, σf . Difficulties in estimating these two pressures independently have limited our ability to estimate the coefficient of soil-root friction, μsr . We used a rotated penetrometer probe, of similar dimensions to a root, and for the first time entering the soil at a similar rate to a root tip, to estimate σn . Separately we measured root penetration resistance (PR) Qr . Root PR was between two to four times σn . We estimated that the coefficient of root-soil friction (μsr ) was 0.21-0.26, based on the geometry of the root tip. This is slightly larger than the 0.05-0.15 characteristic of boundary lubricants. Scanning electron microscopy showed that turgid border cells lined the root channel, supporting our hypothesis that the lubricant consisted of mucilage sandwiched between border cells and the surface of the root cap and epidermis. This cell-cell lubrication greatly decreased the friction that would otherwise be experienced had the surface of the root proper slid directly past unlubricated soil particles. Because root-soil friction can be a substantial component of root PR, successful manipulation of friction represents a promising opportunity for improving plant performance.

  19. 微波对蚕豆根尖细胞的遗传损伤%Microwave radiation-induced genetic damage of root-tip cells in Vicia faba

    Institute of Scientific and Technical Information of China (English)

    罗蔚华; 钱晓薇; 朱睦元

    2012-01-01

    以蚕豆(Vcia faba L.)根尖为实验材料,研究微波辐射对蚕豆根尖细胞的损伤效应.采用蚕豆根尖微核试验和染色体畸变试验方法,以不同处理时间(0~30 s)的微波辐射为诱变剂,测定蚕豆根尖细胞的微核率、有丝分裂指数及染色体畸变率等指标.结果表明:6个时间微波处理组的微核率、染色体畸变率均明显高于阴性对照组(P<0.001).而6个时间微波处理组的有丝分裂指数却明显低于阴性对照组(P<0.001).在本实验处理时间范围内,3个指标均具有一定的时间效应.即随着微波处理时间的延长,微核率及染色体畸变率逐渐升高,而有丝分裂指数则逐渐降低.结论是在该实验微波剂量及处理时间下,微波对蚕豆根尖细胞具有明显的损伤效应.%Microwave radiation-induced genetic damage was investigated in root-tip cells of Vicia faba. Taking the microwave as a mutagen in micronucleus and chromosome aberration assays, mitotic index, micronucleus frequency, and chromosome aberration frequency were detected in time-course treatments of Vicia faba root tip cells. The results showed that micronucleus frequencies, chromosome aberration frequencies in 6 microwave treatment groups were significantly higher than the controlling without microwave treatment (P<0. 001) , while their mitotic index was much lower than that of control group (P<0. 001). During microwave treatments, micronucleus frequency and chromosome aberration frequency were increased in treatment time-dependent manner in root-tip cells, whereas the mitotic index was decreased. These data suggest that microwave causes obvious genetic damage to root-tip cells in Vicia faba.

  20. Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits.

    Science.gov (United States)

    Bengough, A Glyn; McKenzie, B M; Hallett, P D; Valentine, T A

    2011-01-01

    Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances >0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that ∼10% of penetration resistances were >2 MPa at a matric potential of -10 kPa, rising to nearly 50% >2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.

  1. Differential Expression of Proteins and mRNAs from Border Cells and Root Tips of Pea.

    Science.gov (United States)

    Brigham, L. A.; Woo, H. H.; Nicoll, S. M.; Hawes, M. C.

    1995-10-01

    Many plants release large numbers of metabolically active root border cells into the rhizosphere. We have proposed that border cells, cells produced by the root cap meristem that separate from the rest of the root upon reaching the periphery of the cap, are a singularly differentiated part of the root system that modulates the environment of the plant root by producing specific substances to be released into the rhizosphere. Proteins synthesized in border cells exhibit profiles that are very distinct from those of the root tip (root cap, root meristem, and adjacent cells). In vivo-labeling experiments demonstrate that 13% of the proteins that are abundant in preparations from border cells are undetectable in root tip preparations. Twenty-five percent of the proteins synthesized by border cells in a 1-h period are rapidly excreted into the incubation medium. Quantitative variation in levels of specific marker proteins, including glutamine synthetase, heat-shock protein 70, and isoflavone reductase, also occurs between border cells and cells in the root tip. mRNA differential-display assays demonstrate that these large qualitative and quantitative differences in protein expression are correlated with similarly distinct patterns of gene expression. These observations are consistent with the hypothesis that a major switch in gene expression accompanies differentiation into root border cells, as expected for cells with specialized functions in plant development.

  2. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth.

    Science.gov (United States)

    Ivanchenko, Maria G; den Os, Désirée; Monshausen, Gabriele B; Dubrovsky, Joseph G; Bednárová, Andrea; Krishnan, Natraj

    2013-10-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and auxin-resistant mutant, diageotropica (dgt), of tomato (S. lycopersicum 'Ailsa Craig') were characterized in terms of root apical meristem and elongation zone histology, expression of the cell-cycle marker gene Sl-CycB1;1, accumulation of ROS, response to auxin and hydrogen peroxide (H2O2), and expression of ROS-related mRNAs. The dgt mutant exhibited histological defects in the root apical meristem and elongation zone and displayed a constitutively increased level of hydrogen peroxide (H2O2) in the root tip, part of which was detected in the apoplast. Treatments of wild-type with auxin increased the H2O2 concentration in the root tip in a dose-dependent manner. Auxin and H2O2 elicited similar inhibition of cell elongation while bringing forth differential responses in terms of meristem length and number of cells in the elongation zone. Auxin treatments affected the expression of mRNAs of ROS-scavenging enzymes and less significantly mRNAs related to antioxidant level. The dgt mutation resulted in resistance to both auxin and H2O2 and affected profoundly the expression of mRNAs related to antioxidant level. The results indicate that auxin regulates the level of H2O2 in the root tip, so increasing the auxin level triggers accumulation of H2O2 leading to inhibition of root cell elongation and root growth. The dgt mutation affects this pathway by reducing the auxin responsiveness of tissues and by disrupting the H2O2 homeostasis in the root tip.

  3. Aluminium localization in root tips of the aluminium-accumulating plant species buckwheat (Fagopyrum esculentum Moench).

    Science.gov (United States)

    Klug, Benjamin; Specht, André; Horst, Walter J

    2011-11-01

    Aluminium (Al) uptake and transport in the root tip of buckwheat is not yet completely understood. For localization of Al in root tips, fluorescent dyes and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) were compared. The staining of Al with morin is an appropriate means to study qualitatively the radial distribution along the root tip axis of Al which is complexed by oxalate and citrate in buckwheat roots. The results compare well with the distribution of total Al determined by LA-ICP-MS which could be reliably calibrated to compare with Al contents by conventional total Al determination using graphite furnace atomic absorption spectrometry. The Al localization in root cross-sections along the root tip showed that in buckwheat Al is highly mobile in the radial direction. The root apex predominantly accumulated Al in the cortex. The subapical root section showed a homogenous Al distribution across the whole section. In the following root section Al was located particularly in the pericycle and the xylem parenchyma cells. With further increasing distance from the root apex Al could be detected only in individual xylem vessels. The results support the view that the 10 mm apical root tip is the main site of Al uptake into the symplast of the cortex, while the subapical 10-20 mm zone is the main site of xylem loading through the pericycle and xylem parenchyma cells. Progress in the better molecular understanding of Al transport in buckwheat will depend on the consideration of the tissue specificity of Al transport and complexation.

  4. White root tips supply plants with oxygen, water and nutrients

    NARCIS (Netherlands)

    Heuvelink, E.; Kierkels, T.

    2016-01-01

    The main, most important function of roots belonging to horticultural crops is the uptake of water and nutrients. Healthy roots are essential for a healthy plant. After all, if the uptake of water and nutrients is not functioning properly, then other aspects also leave a lot to be desired

  5. The tonoplast intrinsic aquaporin (TIP) subfamily of Eucalyptus grandis: Characterization of EgTIP2, a root-specific and osmotic stress-responsive gene.

    Science.gov (United States)

    Rodrigues, Marcela I; Bravo, Juliana P; Sassaki, Flávio T; Severino, Fábio E; Maia, Ivan G

    2013-12-01

    Aquaporins have important roles in various physiological processes in plants, including growth, development and adaptation to stress. In this study, a gene encoding a root-specific tonoplast intrinsic aquaporin (TIP) from Eucalyptus grandis (named EgTIP2) was investigated. The root-specific expression of EgTIP2 was validated over a panel of five eucalyptus organ/tissues. In eucalyptus roots, EgTIP2 expression was significantly induced by osmotic stress imposed by PEG treatment. Histochemical analysis of transgenic tobacco lines (Nicotiana tabacum SR1) harboring an EgTIP2 promoter:GUS reporter cassette revealed major GUS staining in the vasculature and in root tips. Consistent with its osmotic-stress inducible expression in eucalyptus, EgTIP2 promoter activity was up-regulated by mannitol treatment, but was down-regulated by abscisic acid. Taken together, these results suggest that EgTIP2 might be involved in eucalyptus response to drought. Additional searches in the eucalyptus genome revealed the presence of four additional putative TIP coding genes, which could be individually assigned to the classical TIP1-5 groups.

  6. Effects of bromine on mitosis in root-tips of Allium cepa

    Energy Technology Data Exchange (ETDEWEB)

    Chury, J.; Slouka, V.

    1949-01-01

    The root-tips of Allium cepa, 1.5-2 cm. long, were exposed to pure bromine vapor for five minutes. The root-tips were then washed for ten minutes in water, and kept in fresh-water at a temperature of 20-24/sup 0/C. Squash preparations were made and stained according to the method of Darlington and La Cour. Bromine acting for five minutes on the root-tips of Allium has a specific effect on the cell nucleus in the resting stage. The effects induced are shown thirty-six hours after treatment by spindle abnormalities in metaphase and anaphase, and result in polyploidy in a large number of cells. Bromine produces chromosome and chromatid fragmentation; the latter may be followed by reunion. The effect of the bromine is cumulative and depends on the time which elapses between treatment and fixation. The cytological effects induced by bromine strongly suggest that it is another specific mutafacient chemical.

  7. Externally imposed electric field enhances plant root tip regeneration

    Science.gov (United States)

    Kral, Nicolas; Hanna Ougolnikova, Alexandra

    2016-01-01

    Abstract In plants, shoot and root regeneration can be induced in the distinctive conditions of tissue culture (in vitro) but is also observed in intact individuals (in planta) recovering from tissue damage. Roots, for example, can regenerate their fully excised meristems in planta, even in mutants with impaired apical stem cell niches. Unfortunately, to date a comprehensive understanding of regeneration in plants is still missing. Here, we provide evidence that an imposed electric field can perturb apical root regeneration in Arabidopsis. Crucially, we explored both spatial and temporal competences of the stump to respond to electrical stimulation, by varying respectively the position of the cut and the time interval between excision and stimulation. Our data indicate that a brief pulse of an electric field parallel to the root is sufficient to increase by up to two‐fold the probability of its regeneration, and to perturb the local distribution of the hormone auxin, as well as cell division regulation. Remarkably, the orientation of the root towards the anode or the cathode is shown to play a role. PMID:27606066

  8. Nuclear changes induced by the nematode Xiphinema diversicaudatum in root-tips of strawberry.

    Science.gov (United States)

    Griffiths, B S; Robertson, W M

    1984-03-01

    Feeding by the nematode X. diversicaudatum caused a progressive increase in the DNA content and size of strawberry nuclei. After four days feeding, nuclei had DNA values intermediate between 8C and 16C and had increased in size from a mean of 17 micron2 for control root tips to 49 micron2. Multinucleate cells were present after two and four days feeding. There were no ultrastructural differences in the composition of nuclei from control and parasitized root tips, but strawberry nuclei consisted mainly of dispersed chromatin whereas ryegrass nuclei contained a large proportion of condensed chromatin.

  9. Rhodamine B induces long nucleoplasmic bridges and other nuclear anomalies in Allium cepa root tip cells.

    Science.gov (United States)

    Tan, Dehong; Bai, Bing; Jiang, Donghua; Shi, Lin; Cheng, Shunchang; Tao, Dongbing; Ji, Shujuan

    2014-03-01

    The cytogenetic toxicity of rhodamine B on root tip cells of Allium cepa was investigated. A. cepa were cultured in water (negative control), 10 ppm methyl methanesulfonate (positive control), and three concentrations of rhodamine B (200, 100, and 50 ppm) for 7 days. Rhodamine B inhibited mitotic activity; increased nuclear anomalies, including micronuclei, nuclear buds, and bridged nuclei; and induced oxidative stress in A. cepa root tissues. Furthermore, a substantial amount of long nucleoplasmic bridges were entangled together, and some nuclei were simultaneously linked to several other nuclei and to nuclear buds with nucleoplasmic bridges in rhodamine B-treated cells. In conclusion, rhodamine B induced cytogenetic effects in A. cepa root tip cells, which suggests that the A. cepa root is an ideal model system for detecting cellular interactions.

  10. Species-dependent effects of border cell and root tip exudates on nematode behavior.

    Science.gov (United States)

    Zhao, X; Schmitt, M; Hawes, M C

    2000-11-01

    ABSTRACT Effects of border cell and root tip exudates on root knot nematode (Meloidogyne incognita) behavior were examined. In whole-plant assays using pea, M. incognita second-stage juveniles (J2) accumulated rapidly around the 1- to 2-mm apical region ensheathed by border cells, but not in the region of elongation. Within 15 to 30 min, J2 which had accumulated within detached clumps of border cells lost motility and entered into a quiescent state. When border cells (and associated root tip exudates) were washed from pea roots prior to challenge with nematodes, no such accumulation and quiescence was induced. Attraction of nematodes by roots was species dependent: no attraction or accumulation occurred in snap bean. Using a quantitative assay, three categories of chemotaxis responses occurred: attraction (pea and alfalfa cv. Thor), repulsion (alfalfa cv. Moapa 69), and no response (snap bean and alfalfa cv. Lahonton). In contrast, total root tip exudates from all three plant species acted as a repellent for M. incognita in the sand assay. An in vitro assay was developed to characterize the induced quiescence response. When total root tip exudate from the tested legumes (as well as corn) was incubated with J2 populations, >80% of the nematodes lost motility. A similar response occurred in Caenorhabditis elegans. Border cell exudates did not induce or contribute to the induction of quiescence. Cocultivation of pea border cells with M. incognita resulted in changes in border cell shape similar to those observed in response to exogenous plant hormones. No such changes occurred in snap bean border cells. Understanding the cell- and host-specific extracellular recognition that occurs between roots and pathogenic nematodes in the early stages before infection occurs could lead to new avenues for disease control.

  11. Nitrogen source interacts with ROP signalling in root hair tip-growth.

    Science.gov (United States)

    Bloch, Daria; Monshausen, Gabriele; Singer, Meromit; Gilroy, Simon; Yalovsky, Shaul

    2011-01-01

    Root hairs elongate in a highly polarized manner known as tip growth. Overexpression of constitutively active Rho of Plant (ROP)/RAC GTPases mutants induces swelling of root hairs. Here, we demonstrate that Atrop11(CA)-induced swelling of root hairs depends on the composition of the growth medium. Depletion of ammonium allowed normal root hair elongation in Atrop11(CA) plants, induced the development of longer root hairs in wild-type plants and suppressed the effect of Atrop11(CA) expression on actin organization and reactive oxygen species distribution, whereas membrane localization of the protein was not affected. Ammonium at concentrations higher than 1 mM and the presence of nitrate were required for induction of swelling. Oscillations in wall and cytoplasmic pH are known to accompany tip growth in root hairs, and buffering of the growth medium decreased Atrop11(CA)-induced swelling. Fluorescence ratio imaging experiments revealed that in wild-type root hairs, the addition of NH₄NO₃ to the growth medium induced an increase in the amplitude of extracellular and intracellular pH oscillations and an overall decrease in cytoplasmic pH at the cell apex. Based on these results, we suggest a model in which ROP GTPases and nitrogen-dependent pH oscillations function in parallel pathways, creating a positive feedback loop during root hair growth.

  12. Diversity of an ectomycorrhizal fungal community studied by a root tip and total soil DNA approach

    NARCIS (Netherlands)

    Landeweert, R.; Leeflang, P.; Smit, E.; Kuyper, T.W.

    2005-01-01

    Molecular methods based on soil DNA extracts are increasingly being used to study the fungal diversity of ectomycorrhizal (EM) fungal communities in soil. Contrary to EM root tip identification, the use of molecular methods enables identification of extramatrical mycelia in soil. To compare fungal d

  13. Salt Stress-induced Programmed Cell Death in Rice Root Tip Cells

    Institute of Scientific and Technical Information of China (English)

    Jian-You Li; Ai-Liang Jiang; Wei Zhang

    2007-01-01

    Salt stressed rice root tips were used to investigate the changes of reactive oxygen species (ROS) and antioxidant enzymes at the early stages of programmed cell death (PCD). The results indicated that 500 mmol/L NaCl treatment could lead to specific features of PCD in root tips, such as DNA ladder, nuclear condense and deformation, and transferase mediated dUTP nick end labeling positive reaction, which were initiated at 4 h of treatment and progressed thereafter. Cytochrome c release from mitochondria into cytoplasm was also observed, which occurred at 2 h and was earlier than the above nuclear events. In the very early phase of PCD, an immediate burst in hydrogen peroxide and superoxide anion production rate was accompanied by two-phase changes of superoxide dismutases and ascorbate peroxidase. A short period of increase in the activity was followed by prolonged impairment. Thus,we conclude that salt can induce PCD in rice root tip cells, and propose that in the early phase of rice root tip cell PCD, salt stress-induced oxidative burst increased the antioxidant enzyme activity, which, In turn, scavenged the ROS and abrogated PCD. Also, when the stress is prolonged, the antioxidant system is damaged and accumulated ROS induces the PCD process, which leads to cytochrome c release and nuclear change.

  14. Patterns of auxin and abscisic acid movement in the tips of gravistimulated primary roots of maize

    Science.gov (United States)

    Young, L. M.; Evans, M. L.

    1996-01-01

    Because both abscisic acid (ABA) and auxin (IAA) have been suggested as possible chemical mediators of differential growth during root gravitropism, we compared with redistribution of label from applied 3H-IAA and 3H-ABA during maize root gravitropism and examined the relative basipetal movement of 3H-IAA and 3H-ABA applied to the caps of vertical roots. Lateral movement of 3H-ABA across the tips of vertical roots was non-polar and about 2-fold greater than lateral movement of 3H-IAA (also non-polar). The greater movement of ABA was not due to enhanced uptake since the uptake of 3H-IAA was greater than that of 3H-ABA. Basipetal movement of label from 3H-IAA or 3H-ABA applied to the root cap was determined by measuring radioactivity in successive 1 mm sections behind the tip 90 minutes after application. ABA remained largely in the first mm (point of application) whereas IAA was concentrated in the region 2-4 mm from the tip with substantial levels found 7-8 mm from the tip. Pretreatment with inhibitors of polar auxin transport decreased both gravicurvature and the basipetal movement of IAA. When roots were placed horizontally, the movement of 3H-IAA from top to bottom across the cap was enhanced relative to movement from bottom to top whereas the pattern of movement of label from 3H-ABA was unaffected. These results are consistent with the hypothesis that IAA plays a role in root gravitropism but contrary to the idea that gravi-induced asymmetric distribution of ABA contributes to the response.

  15. [Oxidative damage of volatile oil from Chenopodium ambrosioides on Vicia faba root tip cells].

    Science.gov (United States)

    Hu, Wan-Jun; Ma, Dan-Wei; Wang, Ya-Nan; Zhang, Hong

    2012-04-01

    Chenopodium ambrosioides is an invasive species, which has strong allelopathic effect on surrounding plants. In this study, the methods of soil culture and filter paper culture were adopted to simulate the eluviation and volatilization of the volatile oil from C. ambrosioides, respectively, and to investigate the allelopathy of the volatile oil on the lipid peroxidation and antioxidant enzyme activities of Vicia faba root tip cells, with the mechanisms of the induced tip cell apoptosis analyzed. At the early stage (24 h) of soil culture and filter paper culture, the superoxide dismutase, peroxidase and catalase activities of the tip cells decreased after an initial increase with the increasing dose of the volatile oil, and the malondialdehyde content of the tip cells increased with the increasing volatile oil dose and treated time. At the midterm (48 h) and later (72 h) stages of soil culture and filter paper culture, a typical DNA ladder strip appeared, suggesting that the volatile oil from C. ambrosioides could induce the apoptosis of the tip cells, and the apoptosis was dose- and time dependent. This study showed that the volatile oil from C. ambrosioides could act on its surrounding plants via eluviation and volatilization, making the lipid peroxidation of acceptor plants aggravated and the antioxidant enzyme activities of the plants inhibited, resulting in the oxidative damage and apoptosis of the plant root tip cells, and accordingly, the inhibition of the plant growth. Under soil culture, the root tip cells of V. faba had higher antioxidant enzyme activities and lesser DNA damage, suggesting that the volatile oil from C. ambrosioides via volatilization had stronger allelopathy on the growth of surrounding plants than via eluviation.

  16. Effect of Cinnamomum longepaniculatum allelopathy on the mitosis of Vicia faba root tip cells%宜宾油樟的化感作用对蚕豆根尖细胞有丝分裂的影响

    Institute of Scientific and Technical Information of China (English)

    邓骛远; 罗通; 郑田喜

    2011-01-01

    利用油樟水浸提液作用蚕豆根尖研究了油樟化感作用对蚕豆根尖细胞有丝分裂的影响.结果表明:油樟对蚕豆根尖细胞有丝分裂的化感作用和浸提液浓度、作用时间有密切关系.在实验设计的范围内,随油樟水浸提液浓度的加大,蚕豆根尖细胞有丝分裂指数显著减小,而细胞微核率显著提高;油樟浸提液作用48 h时,对蚕豆根尖细胞有丝分裂的化感作用最强;油樟水浸提液诱导蚕豆根尖细胞产生染色体断片和滞后染色体等多种畸变染色体,并使有丝分裂各时期的分裂相减少.说明油樟化感物质抑制了细胞的有丝分裂,促进微核的产生,从而影响蚕豆根尖的生长和细胞的遗传稳定性.%The effect of Youzhang [Cinnamomum longepaniculatum (Gamble), N.Chan]allelopathy on the mitosis of Vicia faba root tip cells was studied with Youzhang water extracts acting Vicia faba root tips.The result shows the allelopathy has a close relation to the extract concentration and treating time.Within designed range of the experiment, the mitosis index of Vicia faba root tip cells decreases obviously, and the micronucleus frequency rises remarkably along with the increase of Youzhang extract concentrations.When acting time comes to 48 hours, the allelopathy of Youzhang extracts on the mitosis of Vicia faba root tip cells is the strongest.Youzhang water extracts induce a variety of aberrant chromosomes, such as chromosome fregments and delaying chromosomes, and inhibit mitosis different phases.It is implied that Youzhang's allelopthy matter inhibits cell mitosis, and promotes micronucleus generation of cells, and finally affects the growth of Vicia faba root tips and the genetic stability of cells.

  17. Enhancing auxin accumulation in maize root tips improves root growth and dwarfs plant height.

    Science.gov (United States)

    Li, Zhaoxia; Zhang, Xinrui; Zhao, Yajie; Li, Yujie; Zhang, Guangfeng; Peng, Zhenghua; Zhang, Juren

    2017-05-12

    Maize is a globally important food, feed crop and raw material for the food and energy industry. Plant architecture optimization plays important roles in maize yield improvement. PIN-FORMED (PIN) proteins are important for regulating auxin spatiotemporal asymmetric distribution in multiple plant developmental processes. In this study, ZmPIN1a overexpression in maize increased the number of lateral roots and inhibited their elongation, forming a developed root system with longer seminal roots and denser lateral roots. ZmPIN1a overexpression reduced plant height, internode length and ear height. This modification of the maize phenotype increased the yield under high-density cultivation conditions, and the developed root system improved plant resistance to drought, lodging and a low-phosphate environment. IAA concentration, transport capacity determination and application of external IAA indicated that ZmPIN1a overexpression led to increased IAA transport from shoot to root. The increase in auxin in the root enabled the plant to allocate more carbohydrates to the roots, enhanced the growth of the root and improved plant resistance to environmental stress. These findings demonstrate that maize plant architecture can be improved by root breeding to create an ideal phenotype for further yield increases. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  18. Genetic Damage of Root Tip Cells in Broad Bean Plant (Vicia faba) Induced by Water in Liao River Valley%辽河流域水诱发蚕豆根尖细胞遗传损伤的研究

    Institute of Scientific and Technical Information of China (English)

    张利红; 徐成斌; 陈忠林; 苏丹; 王家懿

    2009-01-01

    以辽河流域12个不同断面的河水为诱变剂,运用蚕豆根尖微核检测技术和染色体畸变实验方法,测定蚕豆根尖细胞的有丝分裂指数、微核率和染色体畸变率.结果表明:不同断面的河水均能降低蚕豆根尖细胞有丝分裂指数,能诱发较高频率的微核和染色体畸变,产生染色体断片、核突起和核碎裂.所有样点微核率和染色体畸变率均高于对照组.根据采样点水质污染指数分析町知,福德店水质属重度污染,东辽河、条子河、红庙子水质属中度污染,招苏台河水质属轻度污染.%Water in 12 sections of Liao River Valley was sampled as mutagen and micronucleus test and chromosome aberration assay were used to detect mitotic index,micronucleus ratio and chromosome aberration ratio of root tip cells in broad bean plant(Viciafaba).Results showed that water in different sections can decrease the mitotic index in Vicia faba root tip ceHs,induce higher raftos of either micronucleus or chromosome aberration and produce chromosomal segments,nuclear protuberances and fragments.Micronucleus ratio and chromosome aberration ratio in different sections were higher than those of the control group.Analysis of pollution index in 12 sections showed that water quality Was graded as heavy pollution in Fudedian River,moderate pollution in Dongliao River,Tiaozi River and Hongmiaozi River and light pollution in Zhaosutai River.

  19. Syntaxin of plant proteins SYP123 and SYP132 mediate root hair tip growth in Arabidopsis thaliana.

    Science.gov (United States)

    Ichikawa, Mie; Hirano, Tomoko; Enami, Kazuhiko; Fuselier, Taylor; Kato, Naohiro; Kwon, Chian; Voigt, Boris; Schulze-Lefert, Paul; Baluška, František; Sato, Masa H

    2014-04-01

    Root hairs are fast-growing tubular protrusions on root epidermal cells that play important roles in water and nutrient uptake in plants. The tip-focused polarized growth of root hairs is accomplished by the secretion of newly synthesized materials to the tip via the polarized membrane trafficking mechanism. Here, we report the function of two different types of plasma membrane (PM) Qa-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors), SYP123 and SYP132, in the growth of root hair in Arabidopsis. We found that SYP123, but not SYP132, localizes in the tip region of root hairs by recycling between the brefeldin A (BFA)-sensitive endosomes and the PM of the expanding tip in an F-actin-dependent manner. The vesicle-associated membrane proteins VAMP721/722/724 also exhibited tip-focused localization in root hairs and formed ternary SNARE complexes with both SYP123 and SYP132. These results demonstrate that SYP123 and SYP132 act in a coordinated fashion to mediate tip-focused membrane trafficking for root hair tip growth.

  20. Phytotoxic cyanamide affects maize (Zea mays) root growth and root tip function: from structure to gene expression.

    Science.gov (United States)

    Soltys, Dorota; Rudzińska-Langwald, Anna; Kurek, Wojciech; Szajko, Katarzyna; Sliwinska, Elwira; Bogatek, Renata; Gniazdowska, Agnieszka

    2014-05-01

    Cyanamide (CA) is a phytotoxic compound produced by four Fabaceae species: hairy vetch, bird vetch, purple vetch and black locust. Its toxicity is due to complex activity that involves the modification of both cellular structures and physiological processes. To date, CA has been investigated mainly in dicot plants. The goal of this study was to investigate the effects of CA in the restriction of the root growth of maize (Zea mays), representing the monocot species. CA (3mM) reduced the number of border cells in the root tips of maize seedlings and degraded their protoplasts. However, CA did not induce any significant changes in the organelle structure of other root cells, apart from increased vacuolization. CA toxicity was also demonstrated by its effect on cell cycle activity, endoreduplication intensity, and modifications of cyclins CycA2, CycD2, and histone HisH3 gene expression. In contrast, the arrangement of microtubules was not altered by CA. Treatment of maize seedlings with CA did not completely arrest mitotic activity, although the frequency of dividing cells was reduced. Furthermore, prolonged CA treatment increased the proportion of endopolyploid cells in the root tip. Cytological malformations were accompanied by an induction of oxidative stress in root cells, which manifested as enhanced accumulation of H2O2. Exposure of maize seedlings to CA resulted in an increased concentration of auxin and stimulated ethylene emission. Taken together, these findings suggested that the inhibition of root growth by CA may be a consequence of stress-induced morphogenic responses.

  1. Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

    Science.gov (United States)

    Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

    1987-01-01

    Calcium dependent protein phosphorylation was studied in corn (Zea mays L.) root tips. Prior to in vivo protein phosphorylation experiments, the effect of calcium, ethyleneglycol-bis-(beta-aminoethyl ether)-N-N' -tetraacetic acid (EGTA) and calcium ionophore (A-23187) on phosphorus uptake was studied. Calcium increased phosphorus uptake, whereas EGTA and A-23187 decreased it. Consequently, phosphorus concentration in the media was adjusted so as to attain similar uptake in different treatments. Phosphoproteins were analyzed by two-dimensional gel electrophoresis. Distinct changes in phosphorylation were observed following altered calcium levels. Calcium depletion in root tips with EGTA and A-23187 decreased protein phosphorylation. However, replenishment of calcium following EGTA and ionophore pretreatment enhanced phosphorylation of proteins. Preloading of the root tips with 32P in the presence of EGTA and A-23187 followed by a ten minute calcium treatment, resulted in increased phosphorylation indicating the involvement of calcium, calcium and calmodulin-dependent kinases. Calmodulin antagonist W-7 was effective in inhibiting calcium-promoted phosphorylation. These studies suggest a physiological role for calcium-dependent phosphorylation in calcium-mediated processes in plants.

  2. Macroautophagy occurs in distal TMV-uninfected root tip tissue of tomato taking place systemic PCD.

    Science.gov (United States)

    Zhou, Shumin; Hong, Qiang; Li, Yang; Li, Qi; Li, Ruisha; Zhang, Hongli; Wang, Mao; Yuan, Xiaojun

    2017-05-27

    Autophagy is an important mechanism for recycling cell materials upon encountering stress conditions. Our previous studies had shown that TMV infection could lead to systemic PCD in the distal uninfected tissues, including root tip and shoot tip tissues. But it is not clear whether there is autophagy in the distal apical meristem of TMV-induced plants. To better understand the autophagy process during systemic PCD, here we investigated the formation and type of autophagy in the root meristem cells occurring PCD. Transmission electron microscopy assay revealed that the autophagic structures formed by the fusion of vesicles, containing the sequestered cytoplasm, multilamellar bodies, and degraded mitochondria. In the PCD progress, many mitochondria appeared degradation with blurred inner membrane structure. And the endoplasmic reticulum was broke into small fragments. Finally, the damaged mitochodria were engulfed and degraded by the autophagosomes. These results indicated that during the systemic PCD process of root tip cells, the classical macroautophagy occurred, and the cell contents and damaged organelles (mitochondria) would be self-digested by autophagy.

  3. Rooting greenwood tip cuttings of several Populus clones hydroponically (hydroponic rooting of Populus cuttings)

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, H.M.; Hansen, E.A.; Tolsted, D.N.

    1980-01-01

    Greenwood cuttings of several Populus clones were successfully rooted with a relatively simple hydroponic method. Indolebutyric acid and naphthaleneacetic acid at concentrations of 500 to 5000 ppM applied as a quick dip to the cutting bases, a complete nutrient solution at 20 to 40% of full strength, and a solution temperature between 27 and 30/sup 0/C generally produced the best rooting performance of most clones. Cuttings propagated by the hydroponic procedure rooted faster and generally outgrew those produced by a standard method after being transplanted to pots and grown in the greenhouse.

  4. Specific accumulation and revised structures of acridone alkaloid glucosides in the tips of transformed roots of Ruta graveolens.

    Science.gov (United States)

    Kuzovkina, Inna; Al'terman, Irina; Schneider, Bernd

    2004-04-01

    The root tips of Ruta graveolens (common rue) show strong autofluorescence of acridone alkaloids, which are characteristic secondary metabolites of this plant. To study the specific distribution and accumulation of acridone alkaloids in various root segments of Ruta graveolens, root material was harvested from genetically transformed root cultures and extracts were investigated by chromatographic techniques and HPLC-(1)H NMR spectroscopy. The cells of the elongation and differentiation zones contained acridone glucosides and large amounts of acridone alkaloids, mainly rutacridone. Gravacridondiol glucoside was identified as the dominant secondary compound of the root tips and its structure revised by means of spectroscopic methods. In addition, minor acridones, including the structurally revised gravacridontriol glucoside and unknown natural products, were found in the root tip.

  5. A study of the genetic toxicological action of germinated Solanum tuberosum using micronuclei in Vicia faba root-tip test technique%用蚕豆根尖细胞微核技术研究发芽马铃薯的遗传毒理作用

    Institute of Scientific and Technical Information of China (English)

    蒋梅兰

    2001-01-01

    To explore the genetic toxicological action in germinated Solanum tuberosum, an experiment on the micronucleus frequence of maceration extract of germinated Solanum tuberosum had been carried out with the micronucleus test technique of Vicia faba root-tip cell. The results showed that when the concentrations of maceration extract are 25 g/L, 50 g/L, 100 g/L and 200 g/L, the micronucleus frequence of Vicia faba root-tip cell was 17.21‰, 23.53‰, 29.55‰, 39.40‰ separately. There existed significant differences when compared with negative control, but didn′t cause significant differences as for the non-germinated Solanum tuberosum′s maceration extract with the corresponding concentration to the formation of the micronucleus frequence of Vicia faba root-tip cell when compared with the negative control. Thus,the experiment showed that the formation of micronucleus might be induced greatly by the maceration extract in germination Solanum tuberosum. This technique can be used to test the genetic toxicological action of germinated Solanum tuberosum.%为探讨发芽马铃薯的遗传毒理作用,用蚕豆根尖细胞微核监测技术对发芽马铃薯浸渍液的微核率进行了测定,结果表明:发芽马铃薯浸渍液的质量浓度为25 g/L、50 g/L、100 g/L、200 g/L时,蚕豆根尖细胞微核率分别为17.21‰、23.53‰、29.55‰、39.40‰,与阴性对照组相比存在显著性差异;相应浓度的未发芽马铃薯浸渍液对蚕豆根尖细胞微核率的形成与阴性对照组相比无显著性差异.实验结果提示发芽马铃薯浸渍液能显著诱发蚕豆根尖细胞微核的形成,利用蚕豆根尖细胞微核技术可以监测发芽马铃薯的遗传毒理作用.

  6. Modeling halotropism: a key role for root tip architecture and reflux loop remodeling in redistributing auxin.

    Science.gov (United States)

    van den Berg, Thea; Korver, Ruud A; Testerink, Christa; Ten Tusscher, Kirsten H W J

    2016-09-15

    A key characteristic of plant development is its plasticity in response to various and dynamically changing environmental conditions. Tropisms contribute to this flexibility by allowing plant organs to grow from or towards environmental cues. Halotropism is a recently described tropism in which plant roots bend away from salt. During halotropism, as in most other tropisms, directional growth is generated through an asymmetric auxin distribution that generates differences in growth rate and hence induces bending. Here, we develop a detailed model of auxin transport in the Arabidopsis root tip and combine this with experiments to investigate the processes generating auxin asymmetry during halotropism. Our model points to the key role of root tip architecture in allowing the decrease in PIN2 at the salt-exposed side of the root to result in a re-routing of auxin to the opposite side. In addition, our model demonstrates how feedback of auxin on the auxin transporter AUX1 amplifies this auxin asymmetry, while a salt-induced transient increase in PIN1 levels increases the speed at which this occurs. Using AUX1-GFP imaging and pin1 mutants, we experimentally confirmed these model predictions, thus expanding our knowledge of the cellular basis of halotropism.

  7. Cytotoxicity and genotoxicity evaluation of urban surface waters using freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 and Vicia faba root tip

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan Ma; Xiaochang Wang; Yongjun Liu

    2012-01-01

    The freshwater luminescent bacteria Vibrio-qinghaiensis sp.-Q67 test and the Vicia faba root tip test associated with solid-phase extraction were applied for cytotoxicity and genotoxicity assessment of organic substances in three rivers,two lakes and effluent flows from two wastewater treatment plants (WWTPs) in Xi'an,China.Although the most seriously polluted river with high chemical oxygen demand (COD) and total organic carbon (TOC) showed high cytotoxicity (expressed as TH50,the toxicity impact index) and genotoxicity (expressed as RMCN,the relative frequency of micronucleus),no correlative relation was found between the ecotoxicity and organic content of the water samples.However,there was a linear correlative relation between TⅡ50 and RMCN for most water samples except that from the Zaohe River,which receives discharge from WWTP and untreated industrial wastewaters.The ecotoxicity of the organic toxicants in the Chanhe River and Zaohe River indicated that cytotoxic and genotoxic effects were related to the pollutant source.The TⅡ50 and RMCN were also found to correlate roughly to the dissolved oxygen concentration of the water.Sufficient dissolved oxygen in surface water is thus proved to be an indicator of a healthy water environmental condition.

  8. Exposure to 915 MHz radiation induces micronuclei in Vicia faba root tips.

    Science.gov (United States)

    Gustavino, Bianca; Carboni, Giovanni; Petrillo, Roberto; Paoluzzi, Giovanni; Santovetti, Emanuele; Rizzoni, Marco

    2016-03-01

    The increasing use of mobile phones and wireless networks raised a great debate about the real carcinogenic potential of radiofrequency-electromagnetic field (RF-EMF) exposure associated with these devices. Conflicting results are reported by the great majority of in vivo and in vitro studies on the capability of RF-EMF exposure to induce DNA damage and mutations in mammalian systems. Aimed at understanding whether less ambiguous responses to RF-EMF exposure might be evidenced in plant systems with respect to mammalian ones, in the present work the mutagenic effect of RF-EMF has been studied through the micronucleus (MN) test in secondary roots of Vicia faba seedlings exposed to mobile phone transmission in controlled conditions, inside a transverse electro magnetic (TEM) cell. Exposure of roots was carried out for 72h using a continuous wave (CW) of 915 MHz radiation at three values of equivalent plane wave power densities (23, 35 and 46W/m(2)). The specific absorption rate (SAR) was measured with a calorimetric method and the corresponding values were found to fall in the range of 0.4-1.5W/kg. Results of three independent experiments show the induction of a significant increase of MN frequency after exposure, ranging from a 2.3-fold increase above the sham value, at the lowest SAR level, up to a 7-fold increase at the highest SAR. These findings are in agreement with the limited number of data on cytogenetic effects detected in other plant systems exposed to mobile phone RF-EMF frequencies and clearly show the capability of radiofrequency exposure to induce DNA damage in this eukaryotic cell system.

  9. Gel-free/label-free proteomic analysis of root tip of soybean over time under flooding and drought stresses.

    Science.gov (United States)

    Wang, Xin; Oh, MyeongWon; Sakata, Katsumi; Komatsu, Setsuko

    2016-01-01

    Growth in the early stage of soybean is markedly inhibited under flooding and drought stresses. To explore the responsive mechanisms of soybean, temporal protein profiles of root tip under flooding and drought stresses were analyzed using gel-free/label-free proteomic technique. Root tip was analyzed because it was the most sensitive organ against flooding, and it was beneficial to root penetration under drought. UDP glucose: glycoprotein glucosyltransferase was decreased and increased in soybean root under flooding and drought, respectively. Temporal protein profiles indicated that fermentation and protein synthesis/degradation were essential in root tip under flooding and drought, respectively. In silico protein-protein interaction analysis revealed that the inductive and suppressive interactions between S-adenosylmethionine synthetase family protein and B-S glucosidase 44 under flooding and drought, respectively, which are related to carbohydrate metabolism. Furthermore, biotin/lipoyl attachment domain containing protein and Class II aminoacyl tRNA/biotin synthetases superfamily protein were repressed in the root tip during time-course stresses. These results suggest that biotin and biotinylation might be involved in energy management to cope with flooding and drought in early stage of soybean-root tip.

  10. Phloem-Mobile Aux/IAA Transcripts Target to the Root Tip and Modify Root Architecture

    Institute of Scientific and Technical Information of China (English)

    Michitaka Notaguchi; Shmuel Wolf; William J. Lucas

    2012-01-01

    In plants,the phloem is the component of the vascular system that delivers nutrients and transmits signals from mature leaves to developing sink tissues.Recent studies have identified proteins,mRNA,and small RNA within the phloem sap of several plant species.It is now of considerable interest to elucidate the biological functions of these potential long-distance signal agents,to further our understanding of how plants coordinate their developmental programs at the whole-plant level.In this study,we developed a strategy for the functional analysis of phloem-mobile mRNA by focusing on IAA transcripts,whose mobility has previously been reported in melon (Cucumis melo cv.Hale's Best Jumbo).Indoleacetic acid (IAA) proteins are key transcriptional regulators of auxin signaling,and are involved in a broad range of developmental processes including root development.We used a combination of vasculature-enriched sampling and hetero-grafting techniques to identify IAA18 and IAA28 as phloemmobile transcripts in the model plant Arabidopsis thaliana.Micro-grafting experiments were used to confirm that these IAA transcripts,which are generated in vascular tissues of mature leaves,are then transported into the root system where they negatively regulate lateral root formation.Based on these findings,we present a model in which auxin distribution,in combination with phloem-mobile AuxIIAA transcripts,can determine the sites of auxin action.

  11. Sunlight decreased genotoxicity of azadirachtin on root tip cells of Allium cepa and Eucrosia bicolor.

    Science.gov (United States)

    Kwankua, W; Sengsai, S; Kuleung, C; Euawong, N

    2010-07-01

    Utilization of neem plant (Azadirachta indica A. Juss) extract for pest control in agriculture has raised concerns over contamination by the residues to the environment. Such residues, particularly azadirachtin (Aza), may cause deleterious effect to non-target organisms. This investigation was conducted to find out if Aza could be inactivated through exposures to sunlight. Activity of Aza was assessed as its ability to cause cytotoxic and genotoxic effects in the forms of nuclei abnormality and chromosome aberration as measured by mitotic index (MI) and mitotic aberration (MA). Varying concentrations of Aza were tested on Allium cepa and Eucrosia bicolor. It was found that the MI of all root tip meristematic cells of A. cepa and E. bicolor treated with 0.00005%, 0.00010%, 0.00015%, and 0.00020% (w/v) Aza-containing neem extract for 24h, were significantly lower than the controls. Complementary to the lower levels of MI, the Aza-treated groups showed higher MA levels in all cases investigated. Furthermore, the decreasing levels of MI and the increasing levels of MA related well with the increasing concentration of Aza. Microscopic examination of root tip meristematic cells revealed that the anomaly found most often were mitotic disturbances and chromosomal bridges. Exposures of 0.00020% (w/v) Aza to sunlight for 3 days and 7 days decreased Aza ability to induce cytotoxicity and genotoxicity, both in terms of MI and MA, to root tip meristematic cells in A. cepa and E. bicolor. Photodegradation of Aza upon exposure to direct sunlight was confirmed by HPLC. The study implicates that Aza would unlikely cause long term deleterious effects to the environment since it would be inactivated by sunlight. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  12. Structural Sterols Are Involved in Both the Initiation and Tip Growth of Root Hairs in Arabidopsis thaliana[W

    Science.gov (United States)

    Ovečka, Miroslav; Berson, Tobias; Beck, Martina; Derksen, Jan; Šamaj, Jozef; Baluška, František; Lichtscheidl, Irene K.

    2010-01-01

    Structural sterols are abundant in the plasma membrane of root apex cells in Arabidopsis thaliana. They specifically accumulate in trichoblasts during the prebulging and bulge stages and show a polar accumulation in the tip during root hair elongation but are distributed evenly in mature root hairs. Thus, structural sterols may serve as a marker for root hair initiation and growth. In addition, they may predict branching events in mutants with branching root hairs. Structural sterols were detected using the sterol complexing fluorochrome filipin. Application of filipin caused a rapid, concentration-dependent decrease in tip growth. Filipin-complexed sterols accumulated in globular structures that fused to larger FM4-64–positive aggregates in the tip, so-called filipin-induced apical compartments, which were closely associated with the plasma membrane. The plasma membrane appeared malformed and the cytoarchitecture of the tip zone was affected. Trans-Golgi network/early endosomal compartments containing molecular markers, such as small Rab GTPase RabA1d and SNARE Wave line 13 (VTI12), locally accumulated in these filipin-induced apical compartments, while late endosomes, endoplasmic reticulum, mitochondria, plastids, and cytosol were excluded from them. These data suggest that the local distribution and apical accumulation of structural sterols may regulate vesicular trafficking and plasma membrane properties during both initiation and tip growth of root hairs in Arabidopsis. PMID:20841426

  13. Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of ammonium (NH+4- N ) and ni trate (NO-3- N ) Were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0-3 em)of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO-3 concentration in preculture solution). The results showed that Fe( II ) concentrations in root tip apoplast of maize were only 20-40 nmol/g FW which accounted for 7%-13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH+4 - N or NO-3 - N for 60 min led to an increase of Fe( II ) in root tip apoplast. NH+4 - N led to an increased concentration of Fe( II ) and exchangeable Fe (Fe( II ) and Fe (III)) in root tips, while NO-3 - N increased FeCN reductaseactivity. The relationship between pH and Fe fractions,FeCN reductase activity was also discussed.``

  14. Genotoxicity of five food preservatives tested on root tips of Allium cepa L.

    Science.gov (United States)

    Türkoğlu, Sifa

    2007-01-10

    The effects of the food preservatives sodium benzoate (SB), boric acid (BA), citric acid (CA), potassium citrate (PC) and sodium citrate (SC) have been studied on root tips of Allium cepa L. Roots of A. cepa were treated with a series of concentrations, ranging from 20 to 100 ppm for 5, 10 and 20 h. The results indicate that these food preservatives reduced mitotic division in A. cepa compared with the respective control. Mitotic index values were generally decreased with increasing concentrations and longer treatment times. Additionally, variations in the percentage of mitotic stages were observed. The total percentage of aberrations generally increased with increasing concentrations of these chemicals and the longer period of treatment. Different abnormal mitotic figures were observed in all mitotic phases. Among these abnormalities were anaphase bridges, C-mitosis, micronuclei, lagging, stickiness, breaks and unequal distribution.

  15. Root tip morphology, anatomy, chemistry and potential hydraulic conductivity vary with soil depth in three temperate hardwood species.

    Science.gov (United States)

    Wang, Yan; Dong, Xueyun; Wang, Hongfeng; Wang, Zhengquan; Gu, Jiacun

    2016-01-01

    Root traits in morphology, chemistry and anatomy are important to root physiological functions, but the differences between shallow and deep roots have rarely been studied in woody plants. Here, we selected three temperate hardwood species, Juglans mandshurica Maxim., Fraxinus mandschurica Rupr. and Phellodendron amurense Rupr., in plantations in northeastern China and measured morphological, anatomical and chemical traits of root tips (i.e., the first-order roots) at surface (0-10 cm) and subsurface (20-30 cm) soil layers. The objectives of this study were to identify how those traits changed with soil depth and to reveal potential functional differences. The results showed that root diameters in deep root tips were greater in J. mandshurica and F. mandschurica, but smaller in P. amurense. However, root stele diameter and the ratio of stele to root diameter in the subsurface layer were consistently greater in all three species, which may enhance their abilities to penetrate into soil. All deep roots exhibited lower tissue nitrogen concentration and respiration rate, which were possibly caused by lower nutrient availability in the subsurface soil layer. Significant differences between shallow and deep roots were observed in xylem structure, with deep roots having thicker stele, wider maximum conduit and greater number of conduits per stele. Compared with shallow roots, the theoretical hydraulic conductivities in deep roots were enhanced by 133% (J. mandshurica), 78% (F. mandschurica) and 217% (P. amurense), respectively, indicating higher efficiency of transportation. Our results suggest that trees' root tip anatomical structure and physiological activity vary substantially with soil environment.

  16. Protective role of Royal Jelly (honeybee) on genotoxicity and lipid peroxidation, induced by petroleum wastewater, in Allium cepa L. root tips.

    Science.gov (United States)

    Türkmen, Zafer; Cavuşoğlu, Kültiğin; Cavuşoğlu, Kürşat; Yapar, Kürşad; Yalçin, Emine

    2009-10-01

    In the present study, the protective effect of Royal Jelly (RJ) on genotoxicity and lipid peroxidation, induced by petroleum wastewater, in Allium cepa L. root-tip cells was investigated. For this purpose, we used the malondialdehyde (MDA) level, mitotic index (MI), frequency of micronucleus (MN) and chromosomal aberrations (CAs) as indicators of genotoxicity and lipid peroxidation, and correlated these data with statistical parameters. In additional to the genotoxic analysis, we examined changes in the root anatomy of A. cepa seeds treated with the wastewater. Heavy metal concentrations in the wastewater were measured by atomic absorption spectrophotometry. The seeds were divided into six groups as control, wastewater and RJ treatment groups. They were treated with the wastewater alone, RJ alone (25 and 50 microm doses) and RJ + wastewater for 10 consecutive days. As a result, the mean concentrations of heavy metals in the wastewater were observed to be in the order: Pb > Fe > Al > Ni > Cu > Zn > Cr > Cd. The results showed that there was a significant alteration in MI and in the frequency of MN and CAs in the seeds exposed to the wastewater when compared with the controls. The wastewater exposure resulted in a significant increase in CAs and MN formation (P Heavy metals in the petroleum wastewater significantly increased the MDA production, indicating lipid peroxidation. Moreover, light micrographs showed anatomical damages such as an accumulation of chemical compounds in cortex parenchyma, cell death, an unusual form of cell nucleus and unclear vascular tissue. However, the RJ treatment caused amelioration in the indices of lipid peroxidation and MI, and in the frequency of CAs and MN, when compared with the group treated with petroleum wastewater alone (P effect was observed at dose of 50 microm. In vivo results showed that RJ is a potential protector against toxicity induced by petroleum wastewater, and its protective role is dose-dependent.

  17. [TIPS

    Science.gov (United States)

    Brazzini, Augusto; Carrillo, Alvaro; Cantella, Raúl

    1998-01-01

    Esophageal hemorrage due to variceal bleeding in cirrhotic patients represents a serious problem for the physician in charge, especially in this country where liver transplants are inexistent; and also, it is a drama for the patient and its familly. We propose here the Transjugular Intrahepatic Portosystemic Shunt (TIPS). Twenty one patients were part of a study where 23 TIPS were placed, observing an immediate improval in 18 of them, a rebleeding in 2, within the first 24 and 48 hours. An embolization of the coronary veins was performed in the procedure in 15 patients, and a second intervention due to rebleeding in 2 of them. In the latter patients, the embolization of the coronary veins was rutinary.The survival of the patients has been outstanding.We conclude that this interventional procedure is a worldwide reality in the treatment of esophageal hemorrage by variceal bleeding due to portal hipertension, and it does not cut down the probability of liver transplant, unfortunately inexistent in our country. This procedure results in a low morbimortality with an adequate quality of life.

  18. Mitochondrial complex II-derived superoxide is the primary source of mercury toxicity in barley root tip.

    Science.gov (United States)

    Tamás, Ladislav; Zelinová, Veronika

    2017-02-01

    Enhanced superoxide generation and significant inhibition of succinate dehydrogenase (SDH) activity followed by a strong reduction of root growth were detected in barley seedlings exposed to a 5μM Hg concentration for 30min, which increased further in an Hg dose-dependent manner. While at a 25μM Hg concentration no cell death was detectable, a 50μM Hg treatment triggered cell death in the root meristematic zone, which was markedly intensified after the treatment of roots with 100μM Hg and was detectable in the whole root tips. Generation of superoxide and H2O2 was a very rapid response of root tips occurring even after 5min of exposure to Hg. Application of an NADPH oxidase inhibitor or the inhibition of electron flow in mitochondria by the inhibition of complex I did not influence the Hg-induced H2O2 production. Treatment of roots with thenoyltrifluoroacetone, a non-competitive inhibitor of SDH, markedly reduced root growth and induced both superoxide and H2O2 production in a dose dependent manner. Similar to results obtained in intact roots, Hg strongly inhibited SDH activity in the crude mitochondrial fraction and caused a considerable increase of superoxide production, which was markedly reduced by the competitive inhibitors of SDH. These results indicate that the mitochondrial complex II-derived superoxide is the primary source of Hg toxicity in the barley root tip.

  19. Co-regulation of root hair tip growth by ROP GTPases and nitrogen source modulated pH fluctuations.

    Science.gov (United States)

    Bloch, Daria; Monshausen, Gabriele; Gilroy, Simon; Yalovsky, Shaul

    2011-03-01

    Growth of plant cells involves tight regulation of the cytoskeleton and vesicle trafficking by processes including the action of the ROP small G proteins together with pH-modulated cell wall modifications. Yet, little is known on how these systems are coordinated. In a paper recently published in Plant Cell and Environment we show that ROPs/RACs function synergistically with NH4NO3-modulated pH fluctuations to regulate root hair growth. Root hairs expand exclusively at their apical end in a strictly polarized manner by a process known as tip growth. The highly polarized secretion at the apex is maintained by a complex network of factors including the spatial organization of the actin cytoskeleton, tip-focused ion gradients and by small G proteins. Expression of constitutively active ROP mutants disrupts polar growth, inducing the formation of swollen root hairs. Root hairs are also known to elongate in an oscillating manner, which is correlated with oscillatory H(+) fluxes at the tip. Our analysis shows that root hair elongation in wild type plants and swelling in transgenic plants expressing a constitutively active ROP11 (rop11(CA)) is sensitive to the presence of NH4(+) at concentrations higher than 1 mM and on NO3(-). The NH4(+) and NO3(-) ions did not affect the localization of ROP in the membrane but modulated pH fluctuations at the root hair tip. Actin organization and reactive oxygen species distribution were abnormal in rop11CA root hairs but were similar to wild type root hairs when seedlings were grown on medium lacking NH4(+) and / or NO3(-). These observations suggest that the nitrogen source-modulated pH fluctuations may function synergistically with ROP regulated signaling during root hair tip growth. Interestingly, under certain growth conditions, expression of rop11 (CA) suppressed ammonium toxicity, similar to auxin resistant mutants. In this Addendum article we discuss these findings and their implications.

  20. Mathematical modeling and experimental validation of the spatial distribution of boron in the root of Arabidopsis thaliana identify high boron accumulation in the tip and predict a distinct root tip uptake function.

    Science.gov (United States)

    Shimotohno, Akie; Sotta, Naoyuki; Sato, Takafumi; De Ruvo, Micol; Marée, Athanasius F M; Grieneisen, Verônica A; Fujiwara, Toru

    2015-04-01

    Boron, an essential micronutrient, is transported in roots of Arabidopsis thaliana mainly by two different types of transporters, BORs and NIPs (nodulin26-like intrinsic proteins). Both are plasma membrane localized, but have distinct transport properties and patterns of cell type-specific accumulation with different polar localizations, which are likely to affect boron distribution. Here, we used mathematical modeling and an experimental determination to address boron distributions in the root. A computational model of the root is created at the cellular level, describing the boron transporters as observed experimentally. Boron is allowed to diffuse into roots, in cells and cell walls, and to be transported over plasma membranes, reflecting the properties of the different transporters. The model predicts that a region around the quiescent center has a higher concentration of soluble boron than other portions. To evaluate this prediction experimentally, we determined the boron distribution in roots using laser ablation-inductivity coupled plasma-mass spectrometry. The analysis indicated that the boron concentration is highest near the tip and is lower in the more proximal region of the meristem zone, similar to the pattern of soluble boron distribution predicted by the model. Our model also predicts that upward boron flux does not continuously increase from the root tip toward the mature region, indicating that boron taken up in the root tip is not efficiently transported to shoots. This suggests that root tip-absorbed boron is probably used for local root growth, and that instead it is the more mature root regions which have a greater role in transporting boron toward the shoots.

  1. Cytogenetic studies of chromium (III) oxide nanoparticles on Allium cepa root tip cells.

    Science.gov (United States)

    Kumar, Deepak; Rajeshwari, A; Jadon, Pradeep Singh; Chaudhuri, Gouri; Mukherjee, Anita; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2015-12-01

    The current study evaluates the cytogenetic effects of chromium (III) oxide nanoparticles on the root cells of Allium cepa. The root tip cells of A. cepa were treated with the aqueous dispersions of Cr2O3 nanoparticles (NPs) at five different concentrations (0.01, 0.1, 1, 10, and 100μg/mL) for 4hr. The colloidal stability of the nanoparticle suspensions during the exposure period were ascertained by particle size analyses. After 4hr exposure to Cr2O3 NPs, a significant decrease in mitotic index (MI) from 35.56% (Control) to 35.26% (0.01μg/mL), 34.64% (0.1μg/mL), 32.73% (1μg/mL), 29.6% (10μg/mL) and 20.92% (100μg/mL) was noted. The optical, fluorescence and confocal laser scanning microscopic analyses demonstrated specific chromosomal aberrations such as-chromosome stickiness, chromosome breaks, laggard chromosome, clumped chromosome, multipolar phases, nuclear notch, and nuclear bud at different exposure concentrations. The concentration-dependent internalization/bio-uptake of Cr2O3 NPs may have contributed to the enhanced production of anti oxidant enzyme, superoxide dismutase to counteract the oxidative stress, which in turn resulted in observed chromosomal aberrations and cytogenetic effects. These results suggest that A. cepa root tip assay can be successfully applied for evaluating environmental risk of Cr2O3 NPs over a wide range of concentrations.

  2. Improvement of Vicia-micronucleus test for assessment of soil quality: a proposal for international standardization.

    Science.gov (United States)

    Foltête, Anne-Sophie; Dhyèvre, Adrien; Férard, Jean-François; Cotelle, Sylvie

    2011-11-01

    The Viciafaba root tip micronucleus test is one of the most employed plant genotoxicity assays, and has been used on various types of contaminated materials. This test has been standardized by AFNOR, the French member organization of ISO. However, this test is usually performed with a water extraction step but soil genotoxicity assessment would be more relevant when performed directly in the soil itself. In order to harmonize these protocols, an ISO standard for the V.faba micronucleus test in both liquid phase (exposure of plants to different liquid matrix, including soil water extracts) and solid phase (direct exposure of plants to the soil) would be very useful. In this context, we compared two exposure durations in the solid phase (48 h and 5 d) for the V.faba micronucleus test with two different well-known genotoxicants, maleic hydrazide and copper sulfate. We concluded that these two durations induced equivalent sensitivity: the micronucleus frequency was significantly increased with 5 μmol maleic hydrazide per kg dry soil and with 2 mmol copper sulfate per kg dry soil with both exposure durations. However, exposing roots to soil during 48 h is more practical. Moreover, organically and conventionally cultured seeds were employed to determine whether the seed provenance influenced the test sensitivity. Organic seeds were less sensitive to copper, possibly because copper-based treatments are permitted, and often applied, in organic farms. Therefore, in the absence of completely non-treated seeds, organically-cultured seeds did not appear to offer any advantages over conventional seeds.

  3. Ultrastructure of modified root-tip cells in Ficus carica, induced by the ectoparasitic nematode Xiphinema index.

    Science.gov (United States)

    Wyss, U; Lehmann, H; Jank-Ladwig, R

    1980-02-01

    The migratory ectoparasitic root nematode Xiphinema index, added to Ficus carica seedlings in sterile agar culture, fed exclusively on the tips of the roots. As a response the tips started to swell and became transformed into terminal galls as long as feeding was continued. When the cytology of swollen root-tips was examined 24 h after the first nematode attack, necrotic cells, scattered singly or in small groups within the root apex, were found in ultrathin sections. These cells, whose protoplasts showed features of a hypersensitive reaction, were most probably those fed upon by nematodes. Each necrotic cell was surrounded by several enlarged, mostly binucleate cells with dense cytoplasm. One day later the binucleate cells were multinucleate, containing 4 or even 8 nuclei. The clear-cut demarcation between necrotic and modified cells indicated that only the stimulus for the induction of modified cells but not the stimulus for cell necrosis passed into neighbouring cells. Root-tip galls that provided the appropriate food for egg production in nematodes contained greatly enlarged multinucleate cells between necrotic cells. The modified cells showed features of high metabolic activities, expressed in nuclear and nucleolar hypertrophy, invagination of the nuclear envelope, increased cytoplasmic density, abundance of mitochondria, plastids and rough endoplasmic reticulum. Wall ingrowths, typical of transfer cells, were rare and if present occurred only adjacent to necrotic cells. In older modified cells new cell plates, surrounded by phragmoplasts, were formed.

  4. Mitosis and microtubule organizational changes in rice root-tip cells

    Institute of Scientific and Technical Information of China (English)

    XUSHIXIONG(SYZEE); CHUNGUILI; CHENGZHU

    1993-01-01

    The pattern of change of the microtubule cytoskeleton of the root-tip cells of rice during mitosis was studied using immunofluorescence technic and confocal laser scanning microscopy. All the major stages of ceil division including preprophase, prophase, metaphase, anaphase and telophase were observed. The most significant finding was that in the preprophase cells microtubules radiating from the nuclear surface to the cortex were frequently seen. During development these microtubules became closely associated with the preprophase band and prophase spindie indicating that the microtubules radiating from the nuclear surface, the preprophase band and the prophazc spindle were structurally and functionally closely related to each other. Granule-like anchorage sites for the radiating microtubules at the muclear surface were often seen and the possibility that these gramle-like anchorage sites might represent the microtubule organizing centres was discussed.

  5. Effects of 5-fluorouracil on the mitotic activity of onion root tips apical meristem

    Directory of Open Access Journals (Sweden)

    Waldemar Lechowicz

    2015-01-01

    Full Text Available The effects of various concentrations of 5-FU on the mitotic activity of onion root tips apical meristem were investigated during 24-hour incubation in 5-FU and postincubation in water. The incubation in 5-FU caused a reversible inhibition of mitotic activity, and waves of the partially synchronised mitoses were observed during the period of postincubation. The most pronounced synchronisation of mitoses was obtained after incubation in 100 mg/l. 5-FU but the mitotic index of the resumed mitotic activity amounted to only one half of the control value. 5-FU was found to cause some cytological changes in meristematic cells such as enlargement of the nucleoli, change in the interphasic nuclei structure, appearance of subchromatid and chromatid aberrations and micronuclei. The effects of 5-FU on nucleic acids and the cell division cycle ace discussed and compared with the effects of 5-FUdR.

  6. Effects of cobalt (III) complexes of Schiff bases on root tip mitosis. [Allium cepa

    Energy Technology Data Exchange (ETDEWEB)

    Santanu, T.; Krishna, B.A.; Dhananjoy, K.; Satyabrata, R.; Kamalendu, D.

    1984-01-01

    Cytological effects of two newly synthesized Cobalt (III) complexes, namely, (Co(BSOP)(NH/sub 3/)/sub 2/)(NO/sub 3/), (1) and (Co(BSOP)(PY)/sub 2/)(NO/sub 3/), (2) (where, BSOP = dianion of N,N-orthophenylenebis (salicylaldimine), Py = pyridine) were studied on Allium cepa root tip cells. Many interesting abnormalities, including diplochromatic structure, grouping, stickiness, beadedness, erosion, fragmentation and bridge formation of chromosomes and granulation of the interphase nucleus were observed under the influence of these cobalt (III) complexes. The mitotic index had been simulated at threshold concentrations, but affected at higher concentrations and prolonged treatment. The inhibitory action in prolonged treatment may be due to an accumulation effect. Mechanisms of such effects have been discussed qualitatively and are described as a non-delayed type. 4 figures, 2 tables.

  7. [On the effect of Chinese lacquer upon the cell division of root tip of Allium cepa].

    Science.gov (United States)

    Xing, H; Liang, W

    1997-01-01

    Chinese Lacquer, as a fine coating, has been studied and applied for thousands years. The allergic reaction in Chinese Lacquer on the human skin has also been known early. The reaction of Chinese Lacquer on mitosis of cell in plant meristem have not been reported yet and was carefully studied in this paper. The result showed that Chinese Lacquer induced severe abnormality of mitotic division in Allium cepa root tips. This was more obvious in the anaphase and telophase, especially in the former phase laggard chromosomes, chromosome bridges, acentric fragments and polypolar distribution could be seen frequently. A lot of polynuclear bodies were observed in the telophase. Therefore, we think that the Chinese Lacquer can be used as a plant cell mutagen, and suggest geneticists and physiologists to do more researches on the effects of Chinese Lacquer at the genetic variation, metabolism etc.

  8. 蚕豆微核技术研究洋葱的抗突变作用%The Research of Anti-mutational Function of Allium cepa L. with the Micronucleus Test Technique

    Institute of Scientific and Technical Information of China (English)

    秦永燕; 王旭东; 刘瑞祥; 姚沁涛

    2013-01-01

    Vicia faba root tips micronucleus test to study on effect of water extract of Allium cepa L. on micronucleus rate of Vicia faba root tips induced by cyclophosphamide, which provided the experimental basis for exploiting the antimutation-function of Allium cepa L. When the concentration of water extract of Allium cepa L. was between 0.1 g/mL and 1.0 g/mL, it did not induce micronucleus rate increases, micronucleus index below 1.5. In addition, it could inhibit the micronucleus rate of Vicia faba root tip cells induced by cyclophosphamide, and the rate of inhibitation was between 19.79 % and 66.70 %, which was in some relationship with the concentration of water extract of Allium cepa L. r=0.974 5. The result of research indicated that the water extract of Allium cepa L. had some anti-mutation function.%  利用蚕豆根尖细胞微核试验方法研究洋葱提取液对环磷酰胺诱导蚕豆根尖微核率的影响.当洋葱提取液的浓度在0.1 g/mL~1.0 g/mL之间,不诱导蚕豆根尖微核率的增加,其微核指数均低于1.5;此外,洋葱提取液能够有效地抑制环磷酰胺诱导的蚕豆根尖微核率的增加,抑制率在19.59%~66.70%之间,与其浓度之间存在一定的相关性,r=0.9745.结果表明洋葱提取液具有一定的抗突变作用.

  9. A RAPID DNA EXTRACTION METHOD IS SUCCESSFULLY APPLIED TO ITS-RFLP ANALYSIS OF MYCORRHIZAL ROOT TIPS

    Science.gov (United States)

    A rapid method for extracting DNA from intact, single root tips using a Xanthine solution was developed to handle very large numbers of analyses of ectomycorrhizas. By using an extraction without grinding we have attempted to bias the extraction towards the fungal DNA in the man...

  10. Protonophore- and pH-insensitive glucose and sucrose accumulation detected by FRET nanosensors in Arabidopsis root tips.

    Science.gov (United States)

    Chaudhuri, Bhavna; Hörmann, Friederike; Lalonde, Sylvie; Brady, Siobhan M; Orlando, David A; Benfey, Philip; Frommer, Wolf B

    2008-12-01

    Although soil contains only traces of soluble carbohydrates, plant roots take up glucose and sucrose efficiently when supplied in artificial media. Soluble carbohydrates and other small metabolites found in soil are in part products from exudation from plant roots. The molecular nature of the transporters for uptake and exudation is unknown. Here, fluorescence resonance energy transfer (FRET) glucose and sucrose sensors were used to characterize accumulation and elimination of glucose and sucrose in Arabidopsis roots tips. Using an improved image acquisition set-up, FRET responses to perfusion with carbohydrates were detectable in roots within less than 10 sec and over a wide concentration range. Accumulation was fully reversible within 10-180 sec after glucose or sucrose had been withdrawn; elimination may be caused by metabolism and/or efflux. The rate of elimination was unaffected by pre-incubation with high concentrations of glucose, suggesting that elimination is not due to accumulation in a short-term buffer such as the vacuole. Glucose and sucrose accumulation was insensitive to protonophores, was comparable in media differing in potassium levels, and was similar at pH 5.8, 6.8 and 7.8, suggesting that both influx and efflux may be mediated by proton-independent transport systems. High-resolution expression mapping in root tips showed that only a few proton-dependent transport of the STP (Sugar Transport Protein) and SUT/SUC (Sucrose Transporter/Carrier) families are expressed in the external cell layers of root tips. The root expression maps may help to pinpoint candidate genes for uptake and release of carbohydrates from roots.

  11. Changes in the proteomic and metabolic profiles of Beta vulgaris root tips in response to iron deficiency and resupply

    Directory of Open Access Journals (Sweden)

    Álvarez-Fernández Ana

    2010-06-01

    Full Text Available Abstract Background Plants grown under iron deficiency show different morphological, biochemical and physiological changes. These changes include, among others, the elicitation of different strategies to improve the acquisition of Fe from the rhizosphere, the adjustment of Fe homeostasis processes and a reorganization of carbohydrate metabolism. The application of modern techniques that allow the simultaneous and untargeted analysis of multiple proteins and metabolites can provide insight into multiple processes taking place in plants under Fe deficiency. The objective of this study was to characterize the changes induced in the root tip proteome and metabolome of sugar beet plants in response to Fe deficiency and resupply. Results Root tip extract proteome maps were obtained by 2-D isoelectric focusing polyacrylamide gel electrophoresis, and approximately 140 spots were detected. Iron deficiency resulted in changes in the relative amounts of 61 polypeptides, and 22 of them were identified by mass spectrometry (MS. Metabolites in root tip extracts were analyzed by gas chromatography-MS, and more than 300 metabolites were resolved. Out of 77 identified metabolites, 26 changed significantly with Fe deficiency. Iron deficiency induced increases in the relative amounts of proteins and metabolites associated to glycolysis, tri-carboxylic acid cycle and anaerobic respiration, confirming previous studies. Furthermore, a protein not present in Fe-sufficient roots, dimethyl-8-ribityllumazine (DMRL synthase, was present in high amounts in root tips from Fe-deficient sugar beet plants and gene transcript levels were higher in Fe-deficient root tips. Also, a marked increase in the relative amounts of the raffinose family of oligosaccharides (RFOs was observed in Fe-deficient plants, and a further increase in these compounds occurred upon short term Fe resupply. Conclusions The increases in DMRL synthase and in RFO sugars were the major changes induced by Fe

  12. Effects of soil pH on the Vicia-micronucleus genotoxicity assay.

    Science.gov (United States)

    Dhyèvre, Adrien; Foltête, Anne Sophie; Aran, Delphine; Muller, Serge; Cotelle, Sylvie

    2014-11-01

    In the field of contaminated sites and soil management, chemical analyses only bring typological data about pollution. As far as bioavailability and effects on organisms are concerned, we need ecotoxicology tools. In this domain, among many existing tests, we chose to study genotoxicity because it is a short-term endpoint with long-term consequences. The aim of this study is to assess the effects of soil pH on the results of the Vicia faba root tip micronucleus test for the two following reasons: (i) to define the pH range within which the test can be performed without modifying the soil to be tested, within the framework of the ISO standard of the test and (ii) to provides information about the effects of the pH on the genotoxic potential of soils. In this context, we modified the pH of a standard soil with HCl or NaOH and we spiked the matrix with copper (2, 4 and 8 mmol kg(-1) dry soil) or with maleic hydrazide, an antigerminative chemical (5, 10 and 20 μmol kg(-1) dry soil). We concluded that the pH had no effect on the mitotic index or micronucleus frequency in the root cells of the negative controls: extreme pH values did not induce micronucleus formation in root cells. Moreover, according to our results, the Vicia-micronucleus test can be performed with pH values ranging between 3.2 and 9.0, but in the ISO 29200 "Soil quality--assessment of genotoxic effects on higher plants--V. faba micronucleus test" we recommended to use a control soil with a pH value ranging between 5 and 8 for a more accurate assessment of chemical genotoxicity. We also found that acid pH could increase the genotoxic potential of pollutants, especially heavy metals. With hydrazide maleic spiked soil, plants were placed in a situation of double stress, i.e. toxicity caused by extreme pH values and toxicity induced by the pollutant.

  13. Cytotoxicity of Spent Pot Liner on Allium cepa root tip cells: A comparative analysis in meristematic cell type on toxicity bioassays.

    Science.gov (United States)

    Palmieri, Marcel José; Andrade-Vieira, Larissa Fonseca; Campos, José Marcello Salabert; Dos Santos Gedraite, Leonardo; Davide, Lisete Chamma

    2016-11-01

    Spent Pot Liner (SPL) is a waste generated during the production of aluminum. It is comprised of a mixture of substances most of which, like cyanide, aluminum and fluoride, are toxic. Previous studies indicate the highly toxic nature of SPL. However studies using cells of the differentiation/elongation zone of the root meristem (referred as M2 cells in this study) after a proper recovery period in water were never considered. Using these cells could be useful to further understanding the toxicity mechanisms of SPL. A comparative approach between the effects on M2 cells and meristematic cells of the proximal meristem zone (referred as M1 cells in this study) could lead to understanding how DNA damage caused by SPL behaves on successive generations of cells. Allium cepa cells were exposed to 4 different concentrations of SPL (2.5, 5, 7.5 and 10gL(-1)) mixed with soil and diluted in a CaCl2 0.01M to simulate the ionic forces naturally encountered on the environment. A solution containing only soil diluted on CaCl2 0.01M was used as control. M1 and M2 cells were evaluated separately, taking into account four different parameters: (1) mitotic alterations (MA); (2) presence of condensed nuclei (CN); (3) mitotic index (MI); (4) presence of micronucleus (MCN). Significant differences were observed between M1 and M2 roots tip cells for these four parameters accessed. M1 cells was more prompt to reveal citogenotoxicity through the higher frequency of MA observed. Meanwhile, for M2 cells higher frequencies of MCN and CN was noticed, followed by a reduction of MI. Also, it was possible to detect significant differences between the tested treatments and the control on every case. These results indicate SPL toxic effects carries on to future cells generations. This emphasizes the need to properly manage this waste. Joint evaluation of cells from both M1 and M2 regions was proven valuable for the evaluation of a series of parameters on all toxicity tests.

  14. Effects of the plant steroidal hormone, 24-epibrassinolide, on the mitotic index and growth of onion (Allium cepa) root tips.

    Science.gov (United States)

    Howell, W M; Keller, G E; Kirkpatrick, J D; Jenkins, R L; Hunsinger, R N; McLaughlin, E W

    2007-02-15

    The purpose of the present study was to determine the effects of the steroidal plant hormone, 24-epibrassinolide (BL), on the mitotic index and growth of onion (Allium cepa) root tips. The classical Allium test was used to gather and quantify data on the rate of root growth, the stages of mitosis, and the number of mitoses in control and BL-treated groups of onions. Low doses of BL (0.005 ppm) nearly doubled the mean root length and the number of mitoses over that of controls. Intermediate doses of BL (0.05 ppm) also produced mean root lengths and number of mitoses that were significantly greater than those of the controls. The highest dose of BL (0.5 ppm) produced mean root lengths and number of mitoses that were less than control values, but the differences were not statistically significant. Examination of longitudinally sectioned root tips produced relatively similar results. This study confirms the suppositions of previous authors who have claimed that exogenously applied BL can increase the number of mitoses in plants, but failed to show cytogenetic data. This is the first report detailing the effects of BL on chromosomes and the cell cycle.

  15. Cytological conditions in root tip meristem after gross antagonism of phenylmercuric poisoning

    Energy Technology Data Exchange (ETDEWEB)

    MacFarlane, E.W.E.

    1953-01-01

    The dividing cells of onion root tips were protected by yeast extract, glutathione and cysteine in excess against PMOH 3.4 x 10/sup -5/ M which alone caused clumping of chromosomes in an hour's exposure. Spindle inhibition was not eliminated, but in concentrations of PMOH and of PMN near 10/sup -5/ M it was delayed or more rapidly overcome. The effect was similar to an 80 to 95% reduction in the concentration of the mercurials. A day after antagonism of PMOH 3.4 x 10/sup -5/ M with cysteine 8 x 10/sup -4/ M for an hour, a majority of dividing cells showed mitotic abnormalities characteristic of narcotic concentrations of PMOH. A few showed arrest of metaphase chromosomes on the equator as produced by cysteine alone. Successful antagonism of lethal concentrations of PMN in prolonged exposure was accompanied by accumulation of blocked metaphases. Spindle formation was renewed after return to tap water. In all experiments, even when gross effects were practically eliminated by antagonism with thiols, radiomimetic effects (chromosome fragments and chromatic bridges) appeared in dividing cells after exposure. Effective concentrations of all antagonists by themselves caused mitotic and chromosomal abnormalities. 17 references 2 tables.

  16. Auxin-Independent NAC Pathway Acts in Response to Explant-Specific Wounding and Promotes Root Tip Emergence during de Novo Root Organogenesis in Arabidopsis.

    Science.gov (United States)

    Chen, Xiaodong; Cheng, Jingfei; Chen, Lyuqin; Zhang, Guifang; Huang, Hai; Zhang, Yijing; Xu, Lin

    2016-04-01

    Plants have powerful regenerative abilities that allow them to recover from damage and survive in nature. De novo organogenesis is one type of plant regeneration in which adventitious roots and shoots are produced from wounded and detached organs. By studying de novo root organogenesis using leaf explants of Arabidopsis (Arabidopsis thaliana), we previously suggested that wounding is the first event that provides signals to trigger the whole regenerative process. However, our knowledge of the role of wounding in regeneration remains limited. In this study, we show that wounding not only triggers the auxin-mediated fate transition of regeneration-competent cells, but also induces the NAC pathway for root tip emergence. The NAC1 transcription factor gene was specifically expressed in response to wounding in the leaf explant, but not in the wounded leaf residue of the source plant. Inhibition of the NAC1 pathway severely affected the emergence of adventitious root tips. However, the NAC1 pathway functioned independently of auxin-mediated cell fate transition and regulates expression of CEP genes, which encode proteins that might have a role in degradation of extensin proteins in the cell wall. Overall, our results suggest that wounding has multiple roles in de novo root organogenesis and that NAC1 acts as one downstream branch in regulating the cellular environment for organ emergence.

  17. Lanthanum Prevents Salt Stress-induced Programmed Cell Death in Rice Root Tip Cells by Controlling Early Induction Events

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In a previous study, a salt stress-induced programmed cell death (PCD) model was established in rice root tip cells. Here,by using Wuyunjing 8th rice seedlings, the effects of lanthanum on salt stress-induced PCD early events were studied. The peroxidase (APX). Imidazole (20 mmol/L), the inhibitor of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase), could alleviate the occurrence of PCD obviously, and such alleviation could be enhanced by the addition of La3+,indicating the involvement of NADPH oxidase in the salt stress-induced PCD process. Taken together, lanthanum could prevent salt stress-induced PCD occurrence in the rice root tip cells by blocking the calcium influx under stress, which was followed by inhibiting calcium-dependent NADPH oxidase activity to prevent O2·-production and, enhancing the cytosolic antioxidative enzyme activities to scavenge the reactive oxygen species.

  18. Mutation Effects of Sodium Sulfite and Sodium Nitrite in Root TiP Cells of Vicia Faba%亚硫酸钠和亚硝酸钠对蚕豆根尖细胞致突变作用的研究

    Institute of Scientific and Technical Information of China (English)

    王虹; 王小娟; 高向丽

    2009-01-01

    BACKGROUND AND AIM: We studied the mutation effects of sodium sulfite and sodium nitrite in root tip cells of Vicia faba . MATERIALS AND METHODS: The root tips of Vicia faba were treated with different concentrations of sodium sulfite and sodium nitrite (in the concentrations of 25,50,100,200,400 mg/L) with distilled water as control for four hours.The root tips of Vicia faba were stained with carbol fuchsin and examined. The micronucleus rate and the rate of chromosome aberration were determined within root tip cells of Vicia faba . RESULTS: Different concentrations of sodium sulfite and sodium nitrite increased the micronucleus rate and the rate of chromosome aberration in root tip cells of Vicia faba . Both these rates increased with treatment concentration. The micronucleus rate of sodium nitrite was higher than that of sodium sulfite at the some concentration. Sodium sulfite and sodium nitrite induced chromosome to produce various types of chromosomal aberrations: free chromosome, chromosome fragments, chromosome adhesion, lagging chromosome, chromosome bridge, polarized chromosome and ring chromosome. CONCLUSION: Sodium sulfite and sodium nitrite revealed obvious mutation effects and caused certain genetic toxicity in root tip cells of Vicia faba . The effects of sodium nitrite were stronger than that of sodium nitritet.%背景与目的:研究亚硫酸钠和亚硝酸钠对蚕豆根尖细胞的致突变作用. 材料与方法:用不同浓度的亚硫酸钠和亚硝酸钠(25、50、100、200、400 mg/L)分别处理蚕豆根尖4 h,并以蒸馏水作为对照,用石炭酸品红染液染色,分别观察、测定蚕豆根尖细胞的微核率和染色体畸变率. 结果:与对照组相比,不同浓度的亚硫酸钠和亚硝酸钠均能诱导蚕豆根尖细胞微核率和染色体畸变率增加(P<0.05或P<0.01),且随处理浓度的增大而增加.在相同浓度下,亚硝酸钠诱导的微核率高于亚硫酸钠诱导的微核率.亚硫酸钠和亚硝酸钠诱

  19. 氯化钠对分蘖葱头根尖细胞有丝分裂的影响及其致畸效应%Effect of Sodium Chloride on Mitotic Index and Chromosome Aberration of Root Tip Cell of Allium cepa var. aggreatum

    Institute of Scientific and Technical Information of China (English)

    杨丽娟; 齐莹; 王晓伟; 李岩; 顾地周

    2013-01-01

    With the root tip as experimental materials, toxic effect of sodium chloride on Allium cepa var. aggreatum root tip was investigated. The Allium cepa var. aggreatum root tip cells were exposed to aqueous solution of sodium chloride with different concentration (0.05, 0.1, 0.2, 0.3 mol/L) for 12 h, 24 h and 48 h, respectively. And then the mitotic index, micronucleus rate and chromosome aberration of the Allium cepa var. aggreatum root tip cell were investigated. The experimental results indicated that with the elevated concentrations of sodium chloride aqueous and the increase of exposing time, the mitotic index decreased, chromosome aberration rate and micronucleus rate increased gradually. Moreover, the maximum value was reached when the concentration of sodium chloride aqueous was 0.3 mol/L and the exposure time was 48 h, which indicated that sodium chloride is a kind of stress factor.%以分蘖葱头根尖为试验材料,研究了氯化钠对分蘖葱头根尖的毒性效应.用不同浓度(0.05、0.1、0.2、0.3 mol/L)的氯化钠水溶液对分蘖葱头根尖细胞染毒12h、24 h、48 h,观察分蘖葱头根尖细胞有丝分裂指数、微核率以及染色体畸变情况.结果表明:在试验剂量范围内,随着氯化钠水溶液浓度的升高,染毒时间增长,分蘖葱头根尖细胞的有丝分裂指数逐渐降低,染色体畸变率和微核率逐渐升高,并且均在氯化钠水溶液浓度为0.3 mol/L、染毒时间为48 h时达到最大值,说明氯化钠是一种胁迫因子.

  20. Effects of lead on the morphology and structure of the nucleolus in the root tip meristematic cells of Allium cepa L

    National Research Council Canada - National Science Library

    Jiang, Ze; Zhang, Huaning; Qin, Rong; Zou, Jinhua; Wang, Junran; Shi, Qiuyue; Jiang, Wusheng; Liu, Donghua

    2014-01-01

    To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated...

  1. Heterologous Expression of Panax ginseng PgTIP1 Confers Enhanced Salt Tolerance of Soybean Cotyledon Hairy Roots, Composite, and Whole Plants

    Directory of Open Access Journals (Sweden)

    Jing An

    2017-07-01

    Full Text Available The Panax ginseng TIP gene PgTIP1 was previously demonstrated to have high water channel activity by its heterologous expression in Xenopus laevis oocytes and in yeast; it also plays a significant role in growth of PgTIP1-transgenic Arabidopsis plants under favorable conditions and has enhanced tolerance toward salt and drought treatment. In this work, we first investigated the physiological effects of heterologous PgTIP1 expression in soybean cotyledon hairy roots or composite plants mediated by Agrobacterium rhizogenes toward enhanced salt tolerance. The PgTIP1-transgenic soybean plants mediated by the pollen tube pathway, represented by the lines N and J11, were analyzed at the physiological and molecular levels for enhanced salt tolerance. The results showed that in terms of root-specific heterologous expression, the PgTIP1-transformed soybean cotyledon hairy roots or composite plants displayed superior salt tolerance compared to the empty vector-transformed ones according to the mitigatory effects of hairy root growth reduction, drop in leaf RWC, and rise in REL under salt stress. Additionally, declines in K+ content, increases in Na+ content and Na+/K+ ratios in the hairy roots, stems, or leaves were effectively alleviated by PgTIP1-transformation, particularly the stems and leaves of composite soybean plants. At the whole plant level, PgTIP1-trasgenic soybean lines were found to possess stronger root vigor, reduced root and leaf cell membrane damage, increased SOD, POD, CAT, and APX activities, steadily increased leaf Tr, RWC, and Pn values, and smaller declines in chlorophyll and carotenoid content when exposed to salt stress compared to wild type. Moreover, the distribution patterns of Na+, K+, and Cl- in the roots, stems, and leaves of salt-stressed transgenic plants were readjusted, in that the absorbed Na+ and Cl- were mainly restricted to the roots to reduce their transport to the shoots, and the transport of root-absorbed K+ to the

  2. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth

    NARCIS (Netherlands)

    Ivanchenko, Maria G.; den Os, Desiree; Monshausen, Gabriele B.; Dubrovsky, Joseph G.; Bednarova, Andrea; Krishnan, Natraj

    2013-01-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and auxi

  3. Auxin increases the hydrogen peroxide (H2O2) concentration in tomato (Solanum lycopersicum) root tips while inhibiting root growth

    NARCIS (Netherlands)

    Ivanchenko, Maria G.; den Os, Desiree; Monshausen, Gabriele B.; Dubrovsky, Joseph G.; Bednarova, Andrea; Krishnan, Natraj

    2013-01-01

    The hormone auxin and reactive oxygen species (ROS) regulate root elongation, but the interactions between the two pathways are not well understood. The aim of this study was to investigate how auxin interacts with ROS in regulating root elongation in tomato, Solanum lycopersicum. Wild-type and

  4. Assessment of median lethal dose and anti-mutagenic effects of Glycyrrhiza glabra root extract against chemically induced micronucleus formation in Swiss albino mice

    Directory of Open Access Journals (Sweden)

    Varsha Sharma

    2014-04-01

    Conclusion: Based on this study, it may be concluded that Glycyrrhiza glabra root extract possess anti-mutagenic behavior and this hydro-methanolic crude extract may be safe as per the LD50 was observed. [Int J Basic Clin Pharmacol 2014; 3(2.000: 292-297

  5. Micronucleus assays with Tradescantia pollen tetrads: an update.

    Science.gov (United States)

    Misík, M; Ma, T-H; Nersesyan, A; Monarca, S; Kim, J K; Knasmueller, S

    2011-01-01

    Micronucleus (MN) assays with early pollen tetrad cells of Tradescantia (Trad-MN assays) are at present the most widely used bioassays with plants for the detection of genotoxins in the environment. So far, ∼ 160 chemicals have been tested and ∼ 100 articles that concern complex environmental mixtures were published. This article summarises the results of Trad-MN studies, which have been carried out during the last 15 years with individual compounds and investigations concerning the pollution of environmental compartments (soil, water and air). The evaluation shows that the effects of certain genotoxins such as heavy metals, radionuclides, pesticides and air pollutants can be easily detected with this test. Comparisons with results obtained in MN studies with mitotic (root tip) cells indicate that meiotic tetrad cells are in general more sensitive. Important issues for future research concern the evaluation of the suitability of wildlife Tradescantia species that are sometimes used instead of specific clones (such as #4430 for which standardised protocols have been developed) as well as the assessment of the predictive value of Trad-MN results in regard to the prediction of cancer hazards in humans and adverse effects at the ecosystem level. The fact that the genotoxic effects of certain compound such as metals, which can be detected with plant bioassays, in particular with the Trad-MN assay but not in other commonly used bioassays (e.g. in bacterial tests) makes them an essential element in the batteries for environmental monitoring.

  6. Effects of Mg{sup 2+}, Co{sup 2+}, and Hg{sup 2+} on the nucleus and nucleolus in root tip cells of allium cepa

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D.; Jiang, W.; Wang, W. [Tianjin Normal Univ. (China); Zhai, L. [Xinhua High School, Tianjin (China)

    1995-11-01

    Metal toxicity in plants has been known for a long time. Much importance has increasingly been attached to the problems of metal pollution with the development of modern industry and agriculture. If metals in plants are accumulated to a large extent, it might seriously affect them. The cytological effects of cobalt and mercury have been studied in Allium cepa by documentation of c-mitosis. Also, the quantification of chromosome aberration in Vicia faba root-tip cells treated by magnesium sulphate and in Allium cepa by metyl mercury chloride and mercuric chloride has been reported. Cytological research on the poisoning effects of Mg, Co and Hg on the nuclei and nucleoli in root-tip cells of plants has hardly been reported. The aim of this study was to determine the effects of different concentrations of magnesium, cobalt and mercury ions on root growth, and on the nuclei and nucleoli of root tip cells of Allium-cepa. 20 refs., 3 figs.

  7. Toxicity of CuO Nanoparticles to Structure and Metabolic Activity of Allium cepa Root Tips.

    Science.gov (United States)

    Deng, Fei; Wang, Shuling; Xin, Hua

    2016-11-01

    Roots of Allium cepa were exposed to six CuO NPs suspensions (0, 5, 10, 20, 40, 80 mg L(-1)) in this study. Results revealed that with the increase of CuO NPs concentration, the Cu content in roots increased significantly. Compared to control, onion roots treated with CuO NPs (except 5 mg L(-1) suspension) grew slowly after 24 h. The surface of the root cap and meristematic zone were obviously damaged. The apical meristem of roots treated by 10 mg L(-1) and above concentrations stopped division. The nucleus of meristematic cells deformed, and nucleoli number increased. The plasmolysis occurred, and the cell membrane and nuclear membrane fractured. With the increase of CuO NPs concentration, the MDA content increased, and the root activity decreased. When dealt with 80 mg L(-1) CuO NPs for 72 h, onion roots appeared to be corroded.

  8. Effect of Er,Cr:YSGG Laser Irradiation with Radial Firing Tips on Candida albicans in Experimentally Infected Root Canals

    Directory of Open Access Journals (Sweden)

    Leman Ozkan

    2014-01-01

    Full Text Available Aim. To compare the disinfection effect of Er,Cr:YSGG laser using radial firing tips with NaOCI in root canals infected with C. albicans and to evaluate the irradiation effect on the dentinal surfaces. Material and Methods. In total seventy-six mandibular premolar teeth were used. In order to standardize the incubation and sterilization procedure, eight teeth were used. Sixty-eight of the root canals were incubated with C. albicans suspension for 72 hours. The specimens were divided into 5 experimental groups. Two groups were constituted as Group 1 was irradiated with 1.5 W laser (n=8 and group 2, which was irradiated with 2 W laser (n=8. Two more groups were formed as Group 3 (2 W laser (n=25 and Group 4 NaOCI (5% (n=25. Group 5 (n=2 did not receive any treatment. Mann-Whitney U and Kruskal-Wallis H tests were used to compare the different laser output powers. Wilcoxon Signed Ranks Test was used in order to compare the Candida cfu/ml levels according to treatment protocols (P<0.05. Results. Both 1.5 W and 2 W laser resulted in a major reduction of C. albicans without a significant difference. The comparison of the dentin surfaces irradiated with Er,Cr:YSGG laser at two power settings resulted in similar morphological changes. However, NaOCI was found to be more effective in reduction of C. albicans than 2 W laser application. Conclusion. According to the results of the present study, the Er,Cr:YSGG laser with radial firing tips presented less antifungal effects on C. albicans in root canals of infected teeth than NaOCl solution.

  9. Effects of ultrasonic root-end cavity preparation with different surgical-tips and at different power-settings on glucose-leakage of root-end filling material

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    Betul Gunes

    2014-01-01

    Full Text Available Aim: The aim of this in vitro study was to evaluate the effects of different ultrasonic surgical-tips and power-settings on micro-leakage of root-end filling material. Materials and Methods: The root canals were instrumented using rotary-files and were filled with tapered gutta-percha and root canal sealer using a single-cone technique. The apical 3 mm of each root was resected and the roots were divided into six experimental groups; negative and positive control groups. Root-end cavities were prepared with diamond-coated, zirconum-nitride-coated and stainless-steel ultrasonic retro-tips at half-power and high-power settings. The time required to prepare the root-end cavities for each group was recorded. Root-end cavities were filled with Super-EBA. Leakage values of all samples evaluated with glucose penetration method on 7, 14, 21 and 28 th days. The results were statistically analyzed with Kruskal-Wallis and Hollander-Wolfe tests. Results: The mean time required to prepare retro cavities using diamond-coated surgical tip at high-power setting was significantly less than other groups (P 0.01. Diamond-coated surgical tip showed the least leakage at high-power setting at 3 rd and 4 th weeks (P < 0.01. Conclusions: Under the conditions of this study, cavity preparation time was the shortest and the leakage of the root-end filling was the least when diamond-coated retro-tip used at high-power setting.

  10. Study on Organic Wastewater Monitoring of Laboratory Using MCN Test of Vicia Faba Root Tips%蚕豆根尖细胞微核技术监测实验室有机废水的污染研究

    Institute of Scientific and Technical Information of China (English)

    闫晶晶; 屈艾; 刘小燕; 贾蓉

    2011-01-01

    [ Objective] The genetic toxicity and pollution effects of biological and chemical organic wastewater were studied. [ Method] Organic wastewater which was formed during the preparation of cyclohexanone were diluted eight concentration gradients and detected using MCN test of Vicia faba root tips. [ Results] The results showed that different concentration gradients of organic wastewater had genetic toxicity. In certain concentration range, with the rising of organic wastewater treatment concentration, rate of micronucleus of Vicia faba root tip cells, pollution index and mitotic index gradually increased. However, beyond concentration gradient, organic wastewater restrained Viciafaba cell micro nuclear formation and mitosis. [ Conclusion] Organic wastewater has obvious genetic toxicity and environment pollution effect. VAMCN can be used to monitor and evaluate pollution effect of organic wastewater and the laboratory wastewater after reasonably diluted or eliminate heavy metals can be discharged.%[目的]对生物及化学类实验室的有机废水进行遗传毒性和污染效应的研究.[方法]将实验室条件下制备环已酮时所排有机废水逐级稀释成8个梯度浓度,采用蚕豆(Vicia faba)根尖细胞微核技术进行检测.[结果」不同浓度梯度的实验室有机废水对蚕豆根尖细胞有遗传毒性,在一定浓度范围内,随着废水处理浓度增大,蚕豆根尖细胞微核率、污染指数和有丝分裂指数逐渐增加;但浓度过高,反而会抑制蚕豆根尖细胞微核的形成和有丝分裂的进行.[结论]实验室有机废水有明显的遗传毒性和环境污染效应,可以利用蚕豆根尖细胞微核技术对其污染效应进行监测和评价,实验室废水必须进行合理的处理(稀释或吸附消除重金属)方能排出.

  11. Effect of phthalate esters on micronuclei rates in vicia faba root tip cells%邻苯二甲酸酯类物质对蚕豆根尖细胞微核率的影响

    Institute of Scientific and Technical Information of China (English)

    段丽菊; 王海雪; 高留闯; 唐智敏; 吉宗慧; 范清堂; 崔留欣

    2013-01-01

    OBJECTIVE:To study the mutagenicity of some kinds of phthalate esters. METHODS:Vicia faba root tips were exposed to different concentrations of phthalate esters including dimethyl phthalate,dibuthyl phthalate,bis(2-ethylhexyl) phthalate,diethyl phthalate and dipropyl phthalate for 24 hours. Number of micronuclei of vicia faba root tips cells was observed. RESULTS:Compared with the negative control group,while dimethyl phthalate at the concentration of 0.008,0.016,0.032 mg/L,phthalate dibutyl and phthalate dioctyl at the concentration of 0.016,0.032 mg/L,respectively, there were significant differences in micronucleus rate (P0.05). CONCLUSION:The present study demonstrats that dimethyl phthalate and dibutyl phthalate,dioctyl phthalate displayed genetic toxicity and low concentration of diethyl phthalate and phthalate dipropyl showed no genotoxicity.%目的:研究几种邻苯二甲酸酯类物质的遗传毒性。方法:用不同浓度邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丙酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基己基)酯对蚕豆根尖染毒24 h后,观察蚕豆根尖细胞的微核数。结果:邻苯二甲酸二甲酯在浓度为0.008、0.016和0.032 mg/L,邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基己基)酯在浓度为0.016和0.032 mg/L时,所致蚕豆根尖细胞微核率均显著高于阴性对照组(P0.05)。结论:在本实验条件下,邻苯二甲酸二甲酯、邻苯二甲酸二丁酯、邻苯二甲酸二(2-乙基己基)酯对蚕豆根尖具有遗传毒性,低浓度邻苯二甲酸二乙酯和邻苯二甲酸二丙酯对蚕豆根尖不具有遗传毒性。

  12. Systemic control of cell division and endoreduplication by NAA and BAP by modulating CDKs in root tip cells of Allium cepa.

    Science.gov (United States)

    Tank, Jigna G; Thaker, Vrinda S

    2014-01-01

    Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP) treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed.

  13. Systemic Control of Cell Division and Endoreduplication by NAA and BAP by Modulating CDKs in Root Tip Cells of Allium cepa

    Directory of Open Access Journals (Sweden)

    Jigna G. Tank

    2014-01-01

    Full Text Available Molecular mechanism regulated by auxin and cytokinin during endoreduplication, cell division, and elongation process is studied by using Allium cepa roots as a model system. The activity of CDK genes modulated by auxin and cytokinin during cell division, elongation, and endoreduplication process is explained in this research work. To study the significance of auxin and cytokinin in the management of cell division and endoreduplication process in plant meristematic cells at molecular level endoreduplication was developed in root tips of Allium cepa by giving colchicine treatment. There were inhibition of vegetative growth, formation of c-tumor at root tip, and development of endoreduplicated cells after colchicine treatment. This c-tumor was further treated with NAA and BAP to reinitiate vegetative growth in roots. BAP gave positive response in reinitiation of vegetative growth of roots from center of c-tumor. However, NAA gave negative response in reinitiation of vegetative growth of roots from c-tumor. Further, CDKs gene expression analysis from normal, endoreduplicated, and phytohormone (NAA or BAP treated root tip was done and remarkable changes in transcription level of CDK genes in normal, endoreduplicated, and phytohormones treated cells were observed.

  14. Nuclear changes induced by the nematodes Xiphinema diversicaudatum and Longidorus elongatus in root-tips of perennial ryegrass, Lolium perenne.

    Science.gov (United States)

    Griffiths, B S; Robertson, W M; Trudgill, D L

    1982-09-01

    The DNA content and size of individual nuclei from galls of perennial ryegrass root-tips induced by X. diversicaudatum and L. elongatus were measured. Feeding by X. diversicaudatum increased the DNA content of the nuclei by varying amounts. No regular doubling pattern of the DNA content was discernible. The DNA values varied up to between 32-64C. Generally the size of the nuclei was not increased, although some were larger than control nuclei. The modified nuclei probably have an altered metabolic function, which increases the food value of the gall to the nematode. Some bi-nucleate cells were also observed, which probably result from mitosis without cytokinesis. A preliminary examination of nuclei from galls induced by L. elongatus revealed similar nuclear changes, but no bi-nucleate cells were found.

  15. Induction of micronuclei in Vicia faba root tips treated with heavy metals (cadmium and chromium) in the presence of NTA.

    Science.gov (United States)

    De Marco, A; Paglialunga, S; Rizzoni, M; Testa, A; Trinca, S

    1988-11-01

    Soluble metal compounds (CdCl2, K2Cr2O7) significantly increase the frequency of micronucleated cells in Vicia faba root tips with a clear dose-effect relationship. The addition of NTA (nitrilotriacetic acid) does not enhance the induction of micronucleated cells. Conversely, insoluble metal compounds (CdCO3, PbCRO4) significantly enhance the frequency of micronucleated cells only in the presence of NTA. Since some genotoxic metals are diffused in the environment and are often sequestered as insoluble precipitates in water sediments and sludges, the introduction of NTA is likely to increase the risk of environmental pollution because of its ability to solubilize and make those metals reactive.

  16. Enzymatic adaptations to arsenic-induced oxidative stress in Zea mays and genotoxic effect of arsenic in root tips of Vicia faba and Zea mays.

    Science.gov (United States)

    Duquesnoy, Isabelle; Champeau, Gabrielle Marie; Evray, Germaine; Ledoigt, Gérard; Piquet-Pissaloux, Agnès

    2010-01-01

    Agronomic plant species may display physiological and biochemical responses to oxidative stress caused by heavy metals and metalloids. Zea mays plants were grown hydroponically for eight days at different concentrations of As (0, 134 and 668 μM) and at different pH (4, 7 and 9). Metabolic variations in response to As toxicity were measured using physiological parameters and antioxidant enzymatic activities. A significant decrease in SOD activity was observed in the leaves and roots of Z. mays with the majority of As treatments. As decreased G-POX activity less in leaves than in roots. An increase in the concentration of As increased APX activity in leaves and roots, except As(V) at pH 4 and pH 9 in the leaves and As(III) at pH 9 in the roots, when there was a significant decrease in APX activity at low As concentrations. After exposure to As(V), CAT activity was the same as in the control. As(III) led to an increase in CAT activity in leaves and to a decrease in roots. With increasing concentrations of As(III), CAT activity increased in both leaves and roots whatever the pH. To obtain more detailed knowledge on the effects of arsenate and arsenite exposure on Vicia faba and Z. mays, root meristems were also examined. Roots were fed hydroponically with 134, 334, 534 and 668 μM arsenate or arsenite and 4 × 10(-3)M of maleic hydrazide as positive control, at three different pH. Physiological parameters, the mitotic index and micronuclei frequencies were evaluated in root meristems. At all three pH, the highest As(V) and As(III) concentrations induced a substantial modification in root colour, increased root thickness with stiffening, and reduced root length. High concentrations also caused a significant decrease in the mitotic index, and micronucleus chromosomic aberrations were observed in the root meristems of both species. 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  17. An innovative approach for rubber dam isolation of root end tip: A case report

    Directory of Open Access Journals (Sweden)

    Sunandan Mittal

    2015-01-01

    Full Text Available The success of an apicoectomy with a retrofilling is dependent upon obtaining an acceptable apical seal. The placement of the variously approved retrograde materials requires adequate access, visibility, lighting, and a sterile dry environment. There are instances, however, in which it is difficult to use the rubber dam. One such instance is during retrograde filling. This case report highlights an innovative technique for rubber dam isolation of root end retrograde filling.

  18. Endophytic Microbiota Associated with the Root Tips and Leaves of Baccharis dracunculifolia

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    Raiana S. M. Santana

    Full Text Available ABSTRACT Although endophytic bacteria impact the health, and ultimately the fitness, of their hosts, our understanding of the diversity of endophytic species remains limited. Here we report on the endophytic microbiota inhabiting the roots, healthy leaves and leaves attacked by a gall-inducing insect of Baccharis dracunculifolia, a species of major economic relevance in South America, using 16S rRNA gene new generation sequencing. Rhodoplanes and Nitrospira were well represented in the communities of roots and leaves; known to be important for nitrogen cycling. The difference in bacterial diversity between healthy and galled leaves was not pronounced. The leaves seem to harbor specialized bacteria with high tolerances to abiotic stresses such as wide variation in temperature, low humidity, shallow and nutrient-poor soils and high solar irradiation. These findings suggest taxon-specific ecological niches in the leaves and roots, which may be the result of different physicochemical characteristics between these structures. This study provides a basis for further investigations and adds significant new information to the current knowledge of the endophytic bacterial composition in B. dracunculifolia.

  19. Study of Micronucleus Phenomenon of Vicia faba Induced by Four lnvorment Pollution Reagent%4种环境污染试剂诱导蚕豆微核现象的研究

    Institute of Scientific and Technical Information of China (English)

    杨蓓; 许守明; 赵丽芸; 苏思

    2011-01-01

    [目的]检测4种试剂处理后蚕豆的微核情况,以此评估一些污染物的危害性.[方法]通过蚕豆根尖微核试验,根据微核出现的频率来评价环境诱变因子对蚕豆微核的损害程度,镜捡计数后计算微核率.[结果]甲醛、丙烯酰胺、硝酸铅、O2衍生物可导致蚕豆根尖细胞间期细胞微核频率明显升高,但每种污染物在不同浓度会有不同程度的微核现象,且在一定浓度范围内微核率上升,浓度达到一定值时下降.[结论]丙烯酰胺、甲醛对蚕豆根尖细胞具有明显的遗传毒性效应;硝酸铅对蚕豆根尖细胞不具有明显的遗传毒性效应;SO2衍生物低浓度时对蚕豆根尖细胞有一定遗传毒性效应,高浓度效应明显.%[Objective] The aim was to study micronucleus phenomenon of Vicia faba induced by four invorment pollution reagent in order to assess some of the dangers of pollution. [ Method] By the mature root tip cells of Vicia faba micronucleus in substantial progress in water pollution monitoring, micronucleus phenomenon of Vicia faba induced by four invorment pollution reagent was studied. [Result] It was found that a representative of the environmental pollutants such as formaldehyde, acrylamide, lead nitrate, SO, derivatives could result in root tip cells of Vicia faba micronucleus frequency of interphase cells to increase significantly, but different pollutants at different concentrations varied degrees of micro-nuclear phenomenon, and in a certain range of concentration would increase the micronucleus rate, but would decline. [ Conclusion] Formaldehyde and acrylamide had evident genotoxic effects on root tip cells of Vicia faba, lead nitrate had not evident genotoxic effects, and S02 derivatives had a certain genotoxic effect at low concentration, and had evident genotoxic effects at high concentration.

  20. Cadmium Disrupts the Balance between Hydrogen Peroxide and Superoxide Radical by Regulating Endogenous Hydrogen Sulfide in the Root Tip of Brassica rapa

    Science.gov (United States)

    Lv, Wenjing; Yang, Lifei; Xu, Cunfa; Shi, Zhiqi; Shao, Jinsong; Xian, Ming; Chen, Jian

    2017-01-01

    Cd (cadmium) stress always alters the homeostasis of ROS (reactive oxygen species) including H2O2 (hydrogen sulfide) and O2•– (superoxide radical), leading to the oxidative injury and growth inhibition in plants. In addition to triggering oxidative injury, ROS has been suggested as important regulators modulating root elongation. However, whether and how Cd stress induces the inhibition of root elongation by differentially regulating endogenous H2O2 and O2•–, rather than by inducing oxidative injury, remains elusive. To address these gaps, histochemical, physiological, and biochemical approaches were applied to investigate the mechanism for Cd to fine-tune the balance between H2O2 and O2•– in the root tip of Brassica rapa. Treatment with Cd at 4 and 16 μM significantly inhibited root elongation, while only 16 μM but not 4 μM of Cd induced oxidative injury and cell death in root tip. Fluorescent and pharmaceutical tests suggested that H2O2 and O2•– played negative and positive roles, respectively, in the regulation of root elongation in the presence of Cd (4 μM) or not. Treatment with Cd at 4 μM led to the increase in H2O2 and the decrease in O2•– in root tip, which may be attributed to the up-regulation of Br_UPB1s and the down-regulation of their predicted targets (four peroxidase genes). Cd at 4 μM resulted in the increase in endogenous H2S in root tip by inducing the up-regulation of LCDs and DCDs. Treatment with H2S biosynthesis inhibitor or H2S scavenger significantly blocked Cd (4 μM)-induced increase in endogenous H2S level, coinciding with the recovery of root elongation, the altered balance between H2O2 and O2•–, and the expression of Br_UPB1s and two peroxidase genes. Taken together, it can be proposed that endogenous H2S mediated the phytotoxicity of Cd at low concentration by regulating Br_UPB1s-modulated balance between H2O2 and O2•– in root tip. Such findings shed new light on the regulatory role of endogenous H2S in

  1. Clastogenicity of pentachlorophenol, 2,4-D and butachlor evaluated by Allium root tip test.

    Science.gov (United States)

    Ateeq, Bushra; Abul Farah, M; Niamat Ali, M; Ahmad, Waseem

    2002-02-15

    The meristematic mitotic cells of Allium cepa is an efficient cytogenetic material for chromosome aberration assay on environmental pollutants. For assessing genotoxicity of pentachlorophenol (PCP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-chloro-2,6-diethyl-N-(butoxymethyl) acetanilide (butachlor), 50% effective concentration (EC(50)), c-mitosis, stickiness, chromosome breaks and mitotic index (MI) were used as endpoints of genotoxicity. EC(50) values for PCP and butachlor are 0.73 and 5.13 ppm, respectively. 2,4-D evidently induced morphological changes at higher concentrations. Some changes like crochet hooks, c-tumours and broken roots were unique to 2,4-D at 5-20 ppm. No such abnormalities were found in PCP and butachlor treated groups, however, root deteriorated and degenerated at higher concentrations (butachlor it was recorded 71.6%, which is near to the control value. All chemicals induced chromosome aberrations at statistically significant level. The highest chromosome aberration frequency (11.90%) was recorded in PCP at 3 ppm. Large number of c-mitotic anaphases indicated that butachlor acts as potent spindle inhibitor, whereas, breaks, bridges, stickiness and laggards were most frequently found in PCP showing that it is a potent clastogen.

  2. Cytotoxic Effects of (5 Medicinal Plants on Mitosis in Allium cepa Root Tips

    Directory of Open Access Journals (Sweden)

    I.J. Udo

    2014-03-01

    Full Text Available The study was conducted to investigate the effects that plant extracts from 5 medicinal plants may have on mitosis in Allium cepa. Root of A .cepa were immersed in alcoholic extracts at the concentrations of 0, 25, 50, 75 and 100 mg/mL, respectively for each of the following plants: Gnetum africanum Welw., Lasianther aafricana P. Beauv, Ocimum gratissimum Linn., Telfairia occidentalis Hook F. and Vernonia amygdalina Del. Leafy vegetable which are commonly used in herbal medicine. Results obtained show that the various concentrations of the extracts from test plants had toxic effects on the cells, which caused significant reduction (p<0.05 in the mitotic index when compared with the control. Other effects were prophase inhibition, the delay of mitosis and nuclear lesion. The cytotoxic effect makes a case for a precaution in the use of the leafy extracts in herbal medicine practice.

  3. Novel roles of hydrogen peroxide (H₂O₂) in regulating pectin synthesis and demethylesterification in the cell wall of rice (Oryza sativa) root tips.

    Science.gov (United States)

    Xiong, Jie; Yang, Yongjie; Fu, Guanfu; Tao, Longxing

    2015-04-01

    Hydrogen peroxide (H₂O₂) has been reported to increase lignin formation, enhance cell wall rigidification, restrict cell expansion and inhibit root elongation. However, our results showed that it not only inhibited rice (Oryza sativa) root elongation, but also increased root diameter. No study has reported how and why H₂O₂ increases cell expansion and root diameter. Exogenous H₂O₂ and its scavenger 4-hydroxy-Tempo were applied to confirm the roles of H₂O₂. Immunofluorescence, fluorescence probe, ruthenium red staining, histological section and spectrophotometry were used to monitor changes in the degree of pectin methylesterification, pectin content, pectin methylesterase (PME) activity and H₂O₂ content. Exogenous H₂O₂ inhibited root elongation, but increased cell expansion and root diameter significantly. H₂O₂ not only increased the region of pectin synthesis and pectin content in root tips, but also increased PME activity and pectin demethylesterification. The scavenger 4-hydroxy-Tempo reduced root H₂O₂ content and recovered H₂O₂-induced increases in cell expansion and root diameter by inhibiting pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ plays a novel role in the regulation of pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ increases cell expansion and root diameter by increasing pectin content and demethylesterification.

  4. Effects of Jatropha curcas oil in Lactuca sativa root tip bioassays.

    Science.gov (United States)

    Andrade-Vieira, Larissa F; Botelho, Carolina M; Laviola, Bruno G; Palmieri, Marcel J; Praça-Fontes, Milene M

    2014-03-01

    Jatropha curcas L. (Euphorbiaceae) is important for biofuel production and as a feed ingredient for animal. However, the presence of phorbol esters in the oil and cake renders the seeds toxic. The toxicity of J. curcas oil is currently assessed by testing in animals, leading to their death. The identification of toxic and nontoxic improved varieties is important for the safe use of J. curcas seeds and byproducts to avoid their environmental toxicity. Hence, the aim of this study was to propose a short-term bioassay using a plant as a model to screen the toxicity of J. curcas oil without the need to sacrifice any animals. The toxicity of J. curcas oil was evident in germination, root elongation and chromosomal aberration tests in Lactuca sativa. It was demonstrated that J. curcas seeds contain natural compounds that exert phyto-, cyto- and genotoxic effects on lettuce, and that phorbol esters act as aneugenic agents, leading to the formation of sticky chromosomes and c-metaphase cells. In conclusion, the tests applied have shown reproducibility, which is important to verify the extent of detoxification and to determine toxic doses, thus reducing the numbers of animals that would be used for toxicity tests.

  5. Effects of Jatropha curcas oil in Lactuca sativa root tip bioassays

    Directory of Open Access Journals (Sweden)

    LARISSA F. ANDRADE-VIEIRA

    2014-03-01

    Full Text Available Jatropha curcas L. (Euphorbiaceae is important for biofuel production and as a feed ingredient for animal. However, the presence of phorbol esters in the oil and cake renders the seeds toxic. The toxicity of J. curcas oil is currently assessed by testing in animals, leading to their death. The identification of toxic and nontoxic improved varieties is important for the safe use of J. curcas seeds and byproducts to avoid their environmental toxicity. Hence, the aim of this study was to propose a short-term bioassay using a plant as a model to screen the toxicity of J. curcas oil without the need to sacrifice any animals. The toxicity of J. curcas oil was evident in germination, root elongation and chromosomal aberration tests in Lactuca sativa. It was demonstrated that J. curcas seeds contain natural compounds that exert phyto-, cyto- and genotoxic effects on lettuce, and that phorbol esters act as aneugenic agents, leading to the formation of sticky chromosomes and c-metaphase cells. In conclusion, the tests applied have shown reproducibility, which is important to verify the extent of detoxification and to determine toxic doses, thus reducing the numbers of animals that would be used for toxicity tests.

  6. Wake development behind paired wings with tip and root trailing vortices: consequences for animal flight force estimates.

    Directory of Open Access Journals (Sweden)

    Jan T Horstmann

    Full Text Available Recent experiments on flapping flight in animals have shown that a variety of unrelated species shed a wake behind left and right wings consisting of both tip and root vortices. Here we present an investigation using Particle Image Velocimetry (PIV of the behaviour and interaction of trailing vortices shed by paired, fixed wings that simplify and mimic the wake of a flying animal with a non-lifting body. We measured flow velocities at five positions downstream of two adjacent NACA 0012 aerofoils and systematically varied aspect ratio, the gap between the wings (corresponding to the width of a non-lifting body, angle of attack, and the Reynolds number. The range of aspect ratios and Reynolds number where chosen to be relevant to natural fliers and swimmers, and insect flight in particular. We show that the wake behind the paired wings deformed as a consequence of the induced flow distribution such that the wingtip vortices convected downwards while the root vortices twist around each other. Vortex interaction and wake deformation became more pronounced further downstream of the wing, so the positioning of PIV measurement planes in experiments on flying animals has an important effect on subsequent force estimates due to rotating induced flow vectors. Wake deformation was most severe behind wings with lower aspect ratios and when the distance between the wings was small, suggesting that animals that match this description constitute high-risk groups in terms of measurement error. Our results, therefore, have significant implications for experimental design where wake measurements are used to estimate forces generated in animal flight. In particular, the downstream distance of the measurement plane should be minimised, notwithstanding the animal welfare constraints when measuring the wake behind flying animals.

  7. A maize root tip system to study DNA replication programmes in somatic and endocycling nuclei during plant development.

    Science.gov (United States)

    Bass, Hank W; Wear, Emily E; Lee, Tae-Jin; Hoffman, Gregg G; Gumber, Hardeep K; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

    2014-06-01

    The progress of nuclear DNA replication is complex in both time and space, and may reflect several levels of chromatin structure and 3-dimensional organization within the nucleus. To understand the relationship between DNA replication and developmental programmes, it is important to examine replication and nuclear substructure in different developmental contexts including natural cell-cycle progressions in situ. Plant meristems offer an ideal opportunity to analyse such processes in the context of normal growth of an organism. Our current understanding of large-scale chromosomal DNA replication has been limited by the lack of appropriate tools to visualize DNA replication with high resolution at defined points within S phase. In this perspective, we discuss a promising new system that can be used to visualize DNA replication in isolated maize (Zea mays L.) root tip nuclei after in planta pulse labelling with the thymidine analogue, 5-ethynyl-2'-deoxyuridine (EdU). Mixed populations of EdU-labelled nuclei are then separated by flow cytometry into sequential stages of S phase and examined directly using 3-dimensional deconvolution microscopy to characterize spatial patterns of plant DNA replication. Combining spatiotemporal analyses with studies of replication and epigenetic inheritance at the molecular level enables an integrated experimental approach to problems of mitotic inheritance and cellular differentiation.

  8. Assessment of cytotoxic and genotoxic potential of pyracarbolid by Allium test and micronucleus assay.

    Science.gov (United States)

    Özkara, Arzu; Akyıl, Dilek; Eren, Yasin; Erdoğmuş, S Feyza; Konuk, Muhsin; Sağlam, Esra

    2015-01-01

    The present study evaluates the cytotoxic and genotoxic potential of pyracarbolid using both micronuleus (MN) assay, in human lymphocytes, and Allium cepa assay, in the root meristem cells. In Allium test, EC50 value was determined in order to selecting the test concentrations for the assay and the root tips were treated with 25 ppm (EC50/2), 50 ppm (EC50) and 100 ppm (EC50 × 2) concentrations of pyracarbolid. One percent of dimethyl sulphoxide (DMSO) and methyl methane sulfonate (MMS) were used as negative and positive controls, respectively. In the micronucleus assay, the cultures were treated with four concentrations (250, 500, 750 and 1000 µg/ml) of pyracarbolid for 24 and 48 h, negative and positive controls were also used in the experiment parallely. The results showed that mitotic index (MI) significantly reduced with increasing the pyracarbolid concentration at each exposure time. It was also obtained that prophase and metaphase index decreased significantly in all concentration at each exposure time. Anaphase index decreased as well and results were found to be statistically significant, except 24 h. A significant increase was observed in MN frequency in all concentrations and both treatment periods when compared with the controls. Pyracarbolid also caused a significant reduction in the cytokinesis block proliferation index (CBPI) in all concentration and both exposure time.

  9. Effects of Lead on the Morphology and Structure of the Nucleolus in the Root Tip Meristematic Cells of Allium cepa L.

    OpenAIRE

    Ze Jiang; Huaning Zhang; Rong Qin; Jinhua Zou; Junran Wang; Qiuyue Shi; Wusheng Jiang; Donghua Liu

    2014-01-01

    To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1–1...

  10. Advances in Research of Auxin Signaling in the Root Tip%植物根尖生长素信号研究进展

    Institute of Scientific and Technical Information of China (English)

    沈燕霞; 倪君

    2012-01-01

    Auxin signaling regulates many aspects of plant development. In this article, we gave a brief review of advances in research of auxin signaling in the root tip. We summarized recent progress from three aspects, auxin transport and distribution in root tip, the influences of auxin signaling in root tip cell identities, and auxin signaling in the quiescent center. In addition, we provided prospective views of this field in the end of this article.%生长素信号调控植物生长发育的各个方面.该文综述了生长素信号在植物根尖的研究进展概况,从生长素在根尖的运输与分布、生长素信号对根尖细胞命运的影响及静止中心细胞的生长素信号研究三个方面进行了阐述,并对未来该领域的研究方向进行了展望.

  11. Studies on the endoplasmic reticulum. IV. Its form and distribution during mitosis in cells of onion root tip.

    Science.gov (United States)

    PORTER, K R; MACHADO, R D

    1960-02-01

    Cells of onion and garlic root tips were examined under the electron and phase contrast microscopes after fixation in KMnO(4). Special attention was focused on the distribution and behavior of the endoplasmic reticulum (ER) during the several phases of mitosis. Slender profiles, recognized as sections through thin lamellar units of the ER (most prominent in KMnO(4)-fixed material), are distributed more or less uniformly in the cytoplasm of interphase cells and show occasional continuity with the nuclear envelope. In late prophase the nuclear envelope breaks down and its remnants plus cytoplasmic elements of the ER, which are morphologically identical, surround the spindle in a zone from which mitochondria, etc., are excluded. During metaphase these ER elements persist and concentrate as two separate systems in the polar caps or zones of the spindle. At about this same time they begin to proliferate and to invade the ends of the spindle. The invading lamellar units form drape-like partitions between the anaphase chromosomes. In late anaphase, their advancing margins reach the middle zone of the spindle and begin to fray out. Finally, in telophase, while elements of the ER in the poles of the spindle coalesce around the chromosomes to form the new envelope, the advancing edges of those in the middle zone reticulate at the level of the equator to form a close lattice of tubular elements. Within this, which is identified as the phragmoplast, the earliest signs of the cell plate appear in the form of small vesicles. These subsequently grow and fuse to complete the separation of the two protoplasts. Other morphological units apparently participating in mitosis are described. Speculation is provided on the equal division or not of the nuclear envelope and the contribution the envelope fragments make to the ER of the new cell.

  12. Comparison of the Distances between the Maxillary Sinus Floor and Root-Tips of the First and Second Maxillary Molar Teeth Using Panoramic Radiography among Dolichocephalic and Brachycephalic and Mesocephalic Individuals

    Directory of Open Access Journals (Sweden)

    Hamidreza Arabion

    2015-06-01

    Full Text Available Introduction: Comparison of the relationships and distance between maxillary root tips and   the maxillary sinus floor using oral panoramic in the dolichocephalic and brachycephalic compared to mesocephalic individuals. Methods: Oral panoramic images from 300 individuals were analyzed and the relationships and distance between the maxillary root tips and the sinus floor was assessed by qualitative and quantitative variables. Results: The distance was significantly higher in the brachycephalic groups than that of the mesocephalic, and the mesocephalic group showed longer distance in comparison to dolichocephalic individuals. Qualitative comparison showed that type 1 relationship was the dominant position in the brachycephalic individuals while most of dolichocephalic individuals demonstrated type 2 and 3 relationships of the molar root tips and the maxillary sinus floor. Conclusion: Higher distances between the molar root tips and the maxillary sinus floor could be expected in the brachycephalic than mesocephalic and dolichocephalic individuals

  13. Sealing ability of three root-end filling materials prepared using an erbium: Yttrium aluminium garnet laser and endosonic tip evaluated by confocal laser scanning microscopy

    Science.gov (United States)

    Nanjappa, A Salin; Ponnappa, KC; Nanjamma, KK; Ponappa, MC; Girish, Sabari; Nitin, Anita

    2015-01-01

    Aims: (1) To compare the sealing ability of mineral trioxide aggregate (MTA), Biodentine, and Chitra-calcium phosphate cement (CPC) when used as root-end filling, evaluated under confocal laser scanning microscope using Rhodamine B dye. (2) To evaluate effect of ultrasonic retroprep tip and an erbium:yttrium aluminium garnet (Er:YAG) laser on the integrity of three different root-end filling materials. Materials and Methods: The root canals of 80 extracted teeth were instrumented and obturated with gutta-percha. The apical 3 mm of each tooth was resected and 3 mm root-end preparation was made using ultrasonic tip (n = 30) and Er:YAG laser (n = 30). MTA, Biodentine, and Chitra-CPC were used to restore 10 teeth each. The samples were coated with varnish and after drying, they were immersed in Rhodamine B dye for 24 h. The teeth were then rinsed, sectioned longitudinally, and observed under confocal laser scanning microscope. Statistical Analysis Used: Data were analyzed using one-way analysis of variance (ANOVA) and a post-hoc Tukey's test at P ultrasonics, the difference was found to be statistically significant (P ultrasonics. PMID:26180420

  14. A 3D digital atlas of the Nicotiana tabacum root tip and its use to investigate changes in the root apical meristem induced by the Agrobacterium 6b oncogene.

    Science.gov (United States)

    Pasternak, Taras; Haser, Thomas; Falk, Thorsten; Ronneberger, Olaf; Palme, Klaus; Otten, Léon

    2017-10-01

    Using the intrinsic Root Coordinate System (iRoCS) Toolbox, a digital atlas at cellular resolution has been constructed for Nicotiana tabacum roots. Mitotic cells and cells labeled for DNA replication with 5-ethynyl-2'-deoxyuridine (EdU) were mapped. The results demonstrate that iRoCS analysis can be applied to roots that are thicker than those of Arabidopsis thaliana without histological sectioning. A three-dimensional (3-D) analysis of the root tip showed that tobacco roots undergo several irregular periclinal and tangential divisions. Irrespective of cell type, rapid cell elongation starts at the same distance from the quiescent center, however, boundaries between cell proliferation and transition domains are cell-type specific. The data support the existence of a transition domain in tobacco roots. Cell endoreduplication starts in the transition domain and continues into the elongation zone. The tobacco root map was subsequently used to analyse root organization changes caused by the inducible expression of the Agrobacterium 6b oncogene. In tobacco roots that express the 6b gene, the root apical meristem was shorter and radial cell growth was reduced, but the mitotic and DNA replication indexes were not affected. The epidermis of 6b-expressing roots produced less files and underwent abnormal periclinal divisions. The periclinal division leading to mature endodermis and cortex3 cell files was delayed. These findings define additional targets for future studies on the mode of action of the Agrobacterium 6b oncogene. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  15. Root canal treatment the research status of root tip penetration effect factors%根管治疗造成根尖微渗漏影响因素的研究现状

    Institute of Scientific and Technical Information of China (English)

    张海龙; 董青; 杨光; 苏哲君; 王敬; 张兴乐

    2014-01-01

    根管治疗是现在治疗牙髓病及根尖周病的主要治疗手段。对与根尖周炎的病变,非手术治疗是首选,所以根管治疗的术后微渗漏是根管治疗成败的关键。本研究从根管预备,根管充填,根管糊剂等多方面阐述根尖微渗漏的原因,以及猜想。%Root canal therapy is now main treatment of dental pulp diseases and periapical disease treatment.Lesions of periarthritis with the apex,non-operative treatment is first selection,so the root canal therapy of postoperative micro leakage is the key to a successful root canal treatment.This study from the root canal preparation,root canal fil ing,root canal paste and so on many aspects in this paper, the causes of leakage of root tip micro and guess.

  16. Replicon properties of chromosomal DNA fibers and the duration of DNA synthesis of sunflower root-tip meristem cells at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Van' t Hof, J.; Bjerknes, C.A.; Clinton, J.H.

    1978-01-01

    Chromosomal DNA fiber autoradiography was used to examine the replicon properties of root-tip meristem cells of Helianthus annuus intact seedlings grown at temperatures from 10 to 38/sup 0/C and those of root-tip cells grown in vitro at 23/sup 0/. The average replicon size was approximately 22 ..mu..m and it did not change with temperature nor when the roots were grown in culture. The average fork rate was 6 ..mu..m/h at 10/sup 0/ and it rose gradually to 12 ..mu..m/h at 38/sup 0/. The responses of replication fork movement and of the duration of S to temperature were of three types: those in which change in fork rate was primarily (more than 90%) responsible for change in the duration of S, those in which the fork rate remained constant while S increased nearly twofold, and those in which the duration of S increased even though the replication forks were moving faster. The first type of response listed was observed at temperatures from 20 to 35/sup 0/, the second type listed was observed at 10 to 15/sup 0/, and the third, was produced at 38/sup 0/.

  17. Three major nucleolar proteins migrate from nucleolus to nucleoplasm and cytoplasm in root tip cells of Vicia faba L. exposed to aluminum.

    Science.gov (United States)

    Qin, Rong; Zhang, Huaning; Li, Shaoshan; Jiang, Wusheng; Liu, Donghua

    2014-09-01

    Results from our previous investigation indicated that Al could affect the nucleolus and induce extrusion of silver-staining nucleolar particles containing argyrophilic proteins from the nucleolus into the cytoplasm in root tip cells of Vicia faba L. So far, the nucleolar proteins involved have not been identified. It is well known that nucleophosmin (B23), nucleolin (C23), and fibrillarin are three major and multifunctional nucleolar proteins. Therefore, effects of Al on B23, C23, and fibrillarin in root tip cells of V. faba exposed to 100 μM Al for 48 h were observed and analyzed using indirect immunofluorescence microscopy and Western blotting. The results from this work demonstrated that after 100 μM of Al treatment for 48 h, B23 and C23 migrated from the nucleolus to the cytoplasm and fibrillarin from the nucleolus to the nucleoplasm. In some cells, fibrillarin was present only in the cytoplasm. Western blotting data revealed higher expression of the three major nucleolar proteins in Al-treated roots compared with the control and that the B23 content increased markedly. These findings confirmed our previous observations.

  18. Facilitated transport of Mn2+ in sycamore (Acer pseudoplatanus) cells and excised maize root tips. A comparative 31P n.m.r. study in vivo.

    Science.gov (United States)

    Roby, C; Bligny, R; Douce, R; Tu, S I; Pfeffer, P E

    1988-06-01

    Movement of paramagnetic Mn2+ into sycamore (Acer pseudoplatanus) cells has been indirectly examined by observing the line broadening exhibited in its 31P n.m.r. spectra. Mn2+ was observed to pass into the vacuole, while exhibiting a very minor accumulation in the cytoplasm. With time, gradual leakage of phosphate from the vacuole to the cytoplasm was observed along with an increase in glucose-6-phosphate. Anoxia did not appear to affect the relative distribution of Mn2+ in the cytoplasm and vacuole. Under hypoxic conditions restriction of almost all movement of Mn2+ across the plasmalemma as well as the tonoplast was observed. In contrast, maize root tips showed entry and complete complexation of nucleotide triphosphate by Mn2+ during hypoxia. The rate of passage of Mn2+ across the tonoplast in both sycamore and maize root cells is approximately the same. However, the rates of facilitated movement across the respective plasma membranes appear to differ. More rapid movement of Mn2+ across the plasmalemma in maize root tip cells allows a gradual build-up of metal ion in the cytoplasm prior to its diffusion across the tonoplast. Sycamore cells undergo a slower uptake of Mn2+ into their cytoplasms (comparable with the rate of diffusion through the tonoplast), so little or no observable accumulation of Mn2+ is observed in this compartment.

  19. Promutagen activation of triazine herbicides metribuzin and ametryn through Vicia faba metabolism inducing sister chromatid exchanges in human lymphocytes in vitro and in V. faba root tip meristems.

    Science.gov (United States)

    Flores-Maya, Saúl; Gómez-Arroyo, Sandra; Calderón-Segura, María Elena; Villalobos-Pietrini, Rafael; Waliszewski, Stefan M; de la Cruz, Leticia Gómez

    2005-03-01

    The aim of our study was the induction of sister chromatid exchanges (SCE) in human lymphocytes in vitro and in root tip meristems of Vicia faba to evaluate the genotoxic effects of metribuzin and ametryn. Direct treatments of these herbicides on human lymphocytes in vitro applied 24 h after the beginning of culture did not induce SCE; however, they showed a cytotoxic effect in the cultures expressed as cellular death. On the contrary, when extracts of V. faba roots, treated for 4 h with metribuzin and ametryn (in vivo activation), were added to the lymphocyte cultures, SCEs were significantly induced with an asymptotic response. Negative responses appeared with the in vitro assays, in which metribuzin and ametryn were added directly to the 48 h lymphocyte cultures for 4 h. Nevertheless, in treatments in which the S10 metabolic mix was added, the SCE frequencies were significantly different to the control, although a concentration-response relationship was only observed with metribuzin. The results showed that both herbicides needed the V. faba metabolism to produce SCE in human lymphocyte cultures. Metribuzin and ametryn applied to V. faba root tip meristems for 4 h increased SCE frequency significantly, and a concentration-response relationship was observed with both herbicides.

  20. Border Cells Alleviating Ferrous Toxicity in Rice Root Tips%水稻根尖边缘细胞对铁胁迫的缓解效应

    Institute of Scientific and Technical Information of China (English)

    宋金敏; 刘鹏; 徐根娣; 蔡妙珍; 章艺; 蔡慧姝

    2009-01-01

    A Fe~(2+) tolerant rice variety (Xieyou 9308) and a Fe~(2+) sensitive variety (IR64) screened from 20 rice varieties were used to study the function of border cells in alleviating ferrous toxicity in rice root tips. The relative elongation rates, water content, activities of peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and content of Fe in rice root were measured at 0 (CK) and 200 μmol/L Fe~(2+) for 6 h, 12 h and 24 h respectively, under static culture (to maintain border cells adhered to the root tips) and shaking culture (to remove border cells from root tips completely). The results showed that the relative elongation rates and water content of rice root were reduced by ferrous iron, especially under shaking culture. With the increase of Fe~(2+) treatment time, the relative elongation rates and water content of rice root declined. At the same time, POD, SOD and CAT activities decreased in 200 mg/L Fe~(2+) treatment except the POD activity of Xieyou 9308 under the static culture. The restraining rates of POD, SOD and CAT activities were higher in rice root under the shaking culture. The content of Fe in rice root increased heavily and had a significant difference between CK and Fe~+ stress treatment group. The content of Fe in section of rice root from 0-2 mm to 8-10 mm was increased gradually under the static culture, but had no significant difference in rice root under the shaking culture except the section of 8-10 mm rice root. These results indicate that root border cells play a significant role in resistance to ferrous toxicity of rice.%从20个水稻品种中筛选出较耐亚铁的水稻品种协优9308和敏感品种IR64,采用静置培养(使边缘细胞附于根尖)和摇床培养(移除根尖边缘细胞),测定根相对伸长率、含水量、根尖保护酶(POD、SOD、CAT)活性以及各根段铁含量,研究边缘细胞对水稻根尖铁胁迫的缓解效应.结果表明,铁毒处理抑制根的伸长、降低幼根的含水

  1. Mutagenic Effects of Pesticides Detected by Micronucleus on Different Vicia faba Linn%用微核技术检测农药对不同蚕豆的诱变效应

    Institute of Scientific and Technical Information of China (English)

    孙雁霞; 王跃华; 苟兴华; 苟小军; 邬晓勇; 李文娴

    2011-01-01

    根据发芽率、微核率参数从3种蚕豆种子中筛选最佳的微核实验材料,采用微核技术研究4种农药对蚕豆根尖细胞的诱变效应.结果表明:广元蚕豆种子是最佳的微核实验材料.4种农药单独使用时,农药浓度与微核率呈剂量-效应关系,敌敌畏的诱变效应最大,除它杀虫剂的诱变效应最小.4种农药的最佳使用浓度为:敌敌畏1.9 mg/L,敌杀死-溴氰菊酯2.5mg/L,甲氨基阿维菌素苯甲酸盐1.4 mg/L,除它强力广谱高效杀虫剂2.3 mg/L.%To screen the best Vicia faba for the micronucleus experiment,three broad bean seeds were selected according to the germination rate and the micronucleus rate parameters. Four kinds of pesticides were used to inducce the Vicia faba root-tip by the technology of micronucleus. The results showed that: Cuangyuan bean seed was the best Micronucleus test material. When each of the four pesticides was used alone,the pesticide concentration and micronuclei in a dose-response relationship. The maximum mutagenic effect was the dichlorvos and Chuta was the minimum. The best concentrations of four kinds of pesticides were: dichlorvos 1.9 mg/L,deitamethrin 2. 5 mg/L,dyloxvolaton 1.4 mg/L and ememectin benzoate 2.3 mg/L.

  2. [The role of panoramic radiography in assessing the risk of injury to the inferior alveolar nerve before the extraction of mandibular wisdom teeth. The effect of the extent of root curvature and inferior alveolar canal-root tip overlap on the risk assessment].

    Science.gov (United States)

    Szalma, József; Lempel, Edina; Csuta, Tamás; Bártfai, Dóra; Jeges, Sára; Olasz, Lajos

    2010-06-01

    The aim of the present study was to determine on panoramic radiographic images the effect of the distance between the root curvatures and inferior alveolar canal (IAC) root tip overlap on the surgeon's risk assessment predicting inferior alveolar nerve (IAN) paresthesia after lower third molar removal. In this case-control study 41 cases with postoperative IAN paresthesia and 359 controls without any postoperative complications were involved. Demographic data, root curvatures and the extent of IAC-root tip overlap were registered. The cases of major curvature--larger than 90 degrees (P=0.015; odds ratio [OR]=2.65), the "deepest" superimposition (Pparesthesia. Assessing root curvatures and the extent of IAC-root tip overlap for predicting IAN paresthesia after mandibular third molar removal should help to improve risk assessment.

  3. 40 CFR 79.64 - In vivo micronucleus assay.

    Science.gov (United States)

    2010-07-01

    ... micronucleus assay. (a) Purpose. The micronucleus assay is an in vivo cytogenetic test which uses erythrocytes...) Test evaluation. (i) Positive results in the micronucleus test provide information on the ability of a..., Mammalian Bone Marrow Cytogenetics Tests: Micronucleus Assay. (2) Cihak, R. “Evaluation of Benzidine by...

  4. [Micronucleus test: cytome assay and health biomarker].

    Science.gov (United States)

    García Sagredo, José Miguel

    2012-01-01

    Micronuclei are structures similar to a nucleus but small size and localized in the cytoplasm. A micronucleus contents chromosome fragments or whole chromosomes. The micronucleus test is considered a biomarker for early induced genetic damage. Micronucleus test with cytochalasin B (CBMN test) is used to evaluate genotoxic effects induced by physical and chemical environmental agents, and to estimate the genetic damage induced in population groups exposed to such agents. After the study of large groups of control population, it is estimated that CBMN test can be used as a marker of health status with ability to establish a cancer risk. Finally, recent studies about the onset of cancer, based on single catastrophic events able to originate a cancer, such as chromothripsis or chromoanagenesis, are going to understand through an anomalous replication of DNA within the micronucleus.

  5. Thermal effects from modified endodontic laser tips used in the apical third of root canals with erbium-doped yttrium aluminium garnet and erbium, chromium-doped yttrium scandium gallium garnet lasers.

    Science.gov (United States)

    George, Roy; Walsh, Laurence J

    2010-04-01

    To evaluate the temperature changes occurring on the apical third of root surfaces when erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped yttrium scandium gallium garnet (Er,Cr:YSGG) laser energy was delivered with a tube etched, laterally emitting conical tip and a conventional bare design optical fiber tip. Thermal effects of root canal laser treatments on periodontal ligament cells and alveolar bone are of concern in terms of safety. A total of 64 single-rooted extracted teeth were prepared 1 mm short of the working length using rotary nickel-titanium Pro-Taper files to an apical size corresponding to a F5 Pro-Taper instrument. A thermocouple located 2 mm from the apex was used to record temperature changes arising from delivery of laser energy through laterally emitting conical tips or plain tips, using an Er:YAG or Er,Cr:YSGG laser. For the Er:YAG and Er,Cr:YSGG systems, conical fibers showed greater lateral emissions (452 + 69% and 443 + 64%) and corresponding lower forward emissions (48 + 5% and 49 + 5%) than conventional plain-fiber tips. All four combinations of laser system and fiber design elicited temperature increases less than 2.5 degrees C during lasing. The use of water irrigation attenuated completely the thermal effects of individual lasing cycles. Laterally emitting conical fiber tips can be used safely under defined conditions for intracanal irradiation without harmful thermal effects on the periodontal apparatus.

  6. Modeling wave-like dynamics of oligotrophic and copiotrophic bacteria along wheat roots in response to nutrient input from a growing root tip

    NARCIS (Netherlands)

    Zelenev, V.V.; Bruggen, van A.H.C.; Semenov, A.M.

    2005-01-01

    Dynamics of oligotrophic bacteria (OB) have not been modeled in soil nor along roots. We extended a spatial¿temporal model ¿BACWAVE¿, describing wave-like dynamics of copiotrophic bacteria (CB) isolated on C-rich media to include dynamics of OB isolated on C-poor media and broad-range bacteria (BRB)

  7. Effects of aluminum on nucleoli in root tip cells and selected physiological and biochemical characters in Allium cepa var. agrogarum L

    Directory of Open Access Journals (Sweden)

    Jiang Wusheng

    2010-10-01

    Full Text Available Abstract Background Increased Al concentration causes reduction of mitotic activity, induction of nucleolar alteration, increase of the production of ROS and alteration of several antioxidant enzyme activities in plant cells. Allium cepa is an excellent plant and a useful biomarker for environmental monitoring. Limited information is available about the effects of Al on nucleoli, antioxidant enzyme system, contents of MDA and soluble protein in A. cepa. Therefore, we carried out the investigation in order to better understand the effects of Al on the growth, nucleoli in root tip cells and selected physiological and biochemical characters. Results The results showed that the root growth exposed to 50 μM Al was inhibited significantly. 50 μM Al could induce some particles of argyrophilic proteins scattered in the nuclei and extruded from the nucleoli into the cytoplasm. The nucleolus did not disaggregate normally and still remained its characteristic structure during metaphase. Nucleolar reconstruction was inhibited. 50 μM Al induced high activities of SOD and POD in leaves and roots significantly (P P P th day and in roots increased (P P th day and increased with prolonging the treatment time. Conclusions We suggest that variations in nucleoli and the alterations of antioxidant enzyme activities, MDA and soluble protein contents in Allium cepa can serve as useful biomarkers, which can provide valuable information for monitoring and forecasting effects of exposure to Al in real scenarios conditions. Among the antioxidant enzymes SOD and POD appear to play a key role in the antioxidant defense mechanism under Al toxicity condition. Data from MDA concentration show that Al indirectly produces superoxide radicals, resulting in increased lipid peroxidative products and oxidative stress.

  8. Effects of Fermentative Fluid of Lyophyllum decastes on Mitosis of Root Tip Cells of Allium cepa L. Under NaCl Stress%荷叶离褶伞发酵液对NaCl胁迫下洋葱根尖细胞有丝分裂的影响

    Institute of Scientific and Technical Information of China (English)

    王兴珍; 沈昱彤; 魏生龙; 卯旭辉; 贾秀苹; 梁根生; 王晓琴

    2016-01-01

    The root tip of Allium cepa L is treated with different concentrations of NaCl for 24 hours and 48 hours. The results shows that low concentrations of NaCl significantly promoted the growth of Allium cepa L, but higher concentrations(≥0.1 mol/L) played a poisoned role on the growth of Allium cepa L and have a dose-effect relationship. while we cultured the different NaCl treated Allium cepa L using diluted Fermentative Fluid of Lyophyllum decastes for 24 hours, the result shows that diluted Fermentative Fluid of Lyophyllum decastes can repair the genetic damage and promote the growth of a short period of time NaCl treated Allium cepa L (24 h), such as decreased micronucleus rate and chromosome aberration rate, increased mitotic index, but have a weak role for a long period of time treated NaCl Allium cepa L(48 h).%研究了荷叶离褶伞发酵液对NaCl胁迫下洋葱根尖细胞有丝分裂的影响。结果表明:低浓度NaCl (0.05 mol/L)对洋葱根的生长有促进作用,高浓度NaCl(≥0.10 mol/L)对洋葱根的生长有抑制作用,根尖细胞有丝分裂出现异常,且随着NaCl浓度增高和NaCl处理时间延长抑制作用越明显。荷叶离褶伞发酵液对低浓度NaCl (≤0.10 mol/L)短时间处理(24 h)导致的洋葱根尖细胞遗传损伤有一定的修复作用。

  9. The Cytogenetic Effects of Sodium Metabisulfite, a Food Preservative in Root Tip Cells of Allium cepa L.

    OpenAIRE

    RENCÜZOĞULLARI, Eyyüp

    2001-01-01

    The effects of sodium metabisulfite (SMB) on mitosis were investigated in Allium cepa L. The roots of A. cepa were treated with SMB concentrations of 7.5 mg/lt, 15 mg/lt and 30 mg/lt for 10- and 20-hour treatment periods. SMB significantly decreased the mitotic index (MI) at all concentrations and treatment periods. While the decreasing of the MI was dose-dependent at 10 hours treatment time, SMB increased the mitotic abnormalities dose dependently.

  10. 甘蔗根尖染色体制片技术研究%Studies on Technique of Chromosome Squashing of Root-tip in Sugarcane

    Institute of Scientific and Technical Information of China (English)

    林秀琴; 蔡青; 陆鑫; 应雄美; 毛钧; 苏火生

    2011-01-01

    甘蔗是异源多倍体植物,染色体数目多、体积小,染色体制片困难,导致细胞遗传学研究进展缓慢.以分裂旺盛的甘蔗根尖为材料,对不同采样时间、预处理方法、解离时间、染色方法等各技术环节进行实验研究.结果表明:在冬季气温较低的条件下,于15:00进行采样,饱和对二氯苯与0.002 mol/L 8-羟基喹啉等体积混合液室温预处理4~4.5 h,1 mol/L HCl与45%乙酸等体积混合液于60℃水浴锅解离8min后,用改良苯酚卡宝品红进行涂片滴染,所获得的染色体制片效果最好.%Sugarcane belongs to the allopolyploid plant which contains large number of chromosome with small size. The cytological research on sugarcane may hence be influenced by its difficulties to obtain chromosome products successful. In this paper, the root-tips of sugarcane were used to study the effects of the sampling time, the pretreatment chemical solution, hydrolysing time and staining on the chromosome squashing. The results showed that the optimal sampling time of roots was 15:00 pm under the lower temperature condition in winter. Among the four pretreatment of chemical solutions, the solution mixed with equal volume of saturated p-dichlorobenzene and 0.002 mol/L 8-hydroxyquinoline, was pretreated at room temperature for 4-4.5 h got best result. Root tips were then hydrolysed with the solution mixed by equal volume of 1 mol/L HC1 and 45% acetic acid, for 8 min at 60℃, and stained with modified Carbol fuchsin solution. With this method a very good effect of chromosome squashing could be obtained.

  11. Establishment of the in vitro CottonRoot Tip Culture System%棉花离体根尖培养体系的建立

    Institute of Scientific and Technical Information of China (English)

    祝水金; 季道藩

    2000-01-01

    从培养基成分着手,研究了影响棉花离体根尖培养的各种因素,以建立棉花离体根尖培养体系。研究结果表明,棉花根尖培养的培养基为:MS大量元素+1/2 MS微量元素+100mg·L。肌醇+1.0mg·L。烟酸+10.0mg·L。盐酸硫胺素+L 0mg·L。盐酸吡哆辛+20mg·L。蔗糖+0.125mg·L。吲哚丁酸,用0.8%的琼脂为支撑物,调节pH值为6.4。培养温度为(28±2)℃,每天光照14 h,光照强度为2000 Lx。用此方法进行棉花根尖培养,离体根系可在培养基中生长达2个月而不影响其生活力。该棉花根尖培养体系适用于陆地棉和海岛棉,但基因型之间培养效果存在一定差异。%Conditions of cotton root tip culture invitro were studied in this paper. The recom-mended medium for cotton root tip culture invitro was macronutrients and iron salt of MS ba-sic medium, 1/2 micronutruents of MS basicmedium, vitamins and organic materials of B6basic medium containing 100mg · L-1 of inositol,1.0 mg· L1 of nicotonic acid, 10.0 mg· L-1 ofvitamin B1, 1.0 mg· L4 of vitamin B6, 20 mg ·L-1 of saccharose as the carbon resource and 0. 125 mg · L-t of IBA, using 0. 8% of agar asthe solid material and adjusting pH to 6.4. Thecotton root tips were cultured at a photoperiodof 14 hours daily with a light intensity of 2000Lx and temperature of (28±2)C . The excitedcotton roots could grow very well in the mediumfor more than two months with this culturemethod. This culture system was suitable forthe materials of both G. hirsutum and G. bar-badense, though some differences were presentamong the genotypes.

  12. Sodium chloride stress induces nitric oxide accumulation in root tips and oil body surface accompanying slower oleosin degradation in sunflower seedlings.

    Science.gov (United States)

    David, Anisha; Yadav, Sunita; Bhatla, Satish C

    2010-12-01

    Present work highlights the involvement of endogenous nitric oxide (NO) in sodium chloride (NaCl)-induced biochemical regulation of seedling growth in sunflower (Helianthus annuus L., cv. Morden). The growth response is dependent on NaCl concentration to which seedlings are exposed, they being tolerant to 40 mM NaCl and showing a reduction in extension growth at 120 mM NaCl. NaCl sensitivity of sunflower seedlings accompanies a fourfold increase in Na(+) /K(+) ratio in roots (as compared to that in cotyledons) and rapid transport of Na(+) to the cotyledons, thereby enhancing Na(+) /K(+) ratio in cotyledons as well. A transient increase in endogenous NO content, primarily contributed by putative NOS activity in roots of 4-day-old seedlings subjected to NaCl stress and the relative reduction in Na(+) /K(+) ratio after 4 days, indicates that NO regulates Na(+) accumulation, probably by affecting the associated transporter proteins. Root tips exhibit an early and transient enhanced expression of 4,5-diaminofluorescein diacetate (DAF-2DA) positive NO signal in the presence of 120 mM NaCl. Oil bodies from 2-day-old seedling cotyledons exhibit enhanced localization of NO signal in response to 120 mM NaCl treatment, coinciding with a greater retention of the principal oil body membrane proteins, i.e. oleosins. Abolition of DAF positive fluorescence by the application of specific NO scavenger [2-phenyl-4,4,5,5-tetramethyllimidazoline-1-oxyl-3-oxide (PTIO)] authenticates the presence of endogenous NO. These novel findings provide evidence for a possible protective role of NO during proteolytic degradation of oleosins prior to/accompanying lipolysis.

  13. Macromolecular differentiation of Golgi stacks in root tips of Arabidopsis and Nicotiana seedlings as visualized in high pressure frozen and freeze-substituted samples

    Science.gov (United States)

    Staehelin, L. A.; Giddings, T. H. Jr; Kiss, J. Z.; Sack, F. D.

    1990-01-01

    The plant root tip represents a fascinating model system for studying changes in Golgi stack architecture associated with the developmental progression of meristematic cells to gravity sensing columella cells, and finally to "young" and "old", polysaccharide-slime secreting peripheral cells. To this end we have used high pressure freezing in conjunction with freeze-substitution techniques to follow developmental changes in the macromolecular organization of Golgi stacks in root tips of Arabidopsis and Nicotiana. Due to the much improved structural preservation of all cells under investigation, our electron micrographs reveal both several novel structural features common to all Golgi stacks, as well as characteristic differences in morphology between Golgi stacks of different cell types. Common to all Golgi stacks are clear and discrete differences in staining patterns and width of cis, medial and trans cisternae. Cis cisternae have the widest lumina (approximately 30 nm) and are the least stained. Medial cisternae are narrower (approximately 20 nm) and filled with more darkly staining products. Most trans cisternae possess a completely collapsed lumen in their central domain, giving rise to a 4-6 nm wide dark line in cross-sectional views. Numerous vesicles associated with the cisternal margins carry a non-clathrin type of coat. A trans Golgi network with clathrin coated vesicles is associated with all Golgi stacks except those of old peripheral cells. It is easily distinguished from trans cisternae by its blebbing morphology and staining pattern. The zone of ribosome exclusion includes both the Golgi stack and the trans Golgi network. Intercisternal elements are located exclusively between trans cisternae of columella and peripheral cells, but not meristematic cells. In older peripheral cells only trans cisternae exhibit slime-related staining. Golgi stacks possessing intercisternal elements also contain parallel rows of freeze-fracture particles in their trans

  14. PI3K is involved in nucleolar structure and function on root-tip meristematic cells of Triticum aestivum L.

    Science.gov (United States)

    Ni, Xiaolin; Zhang, Feixiong

    2014-06-01

    In this study, wheat (Triticum aestivum L.) seeds were used to detect the effect of wortmannin, a specific inhibitor of PI3K, on the nucleolar structure and function. When the germinated seeds were treated with wortmannin, it was shown that the root growth was suppressed and the mitotic index was decreased. The inhibition effects were positively correlated with the concentrations of the drug. The observations of light and transmission electron microscopy revealed that the nucleolar morphology became irregular and their fine structure disappeared. Some granules with a size range of 0.05-0.30 μm diffused from the nucleoli and gradually moved to the nucleoplasm between or around the chromatin. Indirect immunofluorescence staining indicated that B23 shuttled from the nucleoli to the nucleoplasm, or even, to the cytoplasm. RT-PCR technique demonstrated that the expression of C23 was severely down-regulated. Our results suggest, for the first time, that wortmannin treatment can not only damage nucleolar structure, but also inhibit its function, implying that PI3K is involved in nucleolar structure and function.

  15. Involvement of PME activity in regulation of Al toxic sensitivity in the root tips of barley%果胶甲基酯酶PME参与调控大麦根尖铝毒敏感性

    Institute of Scientific and Technical Information of China (English)

    潘伟槐; 郑仲仲; 郭天荣; 王超; 寿建昕; 潘建伟

    2011-01-01

    It has been proposed that Aluminum(Al) accumulation on cell walls of root tips is the primary prerequisite of toxic effects of Al on root tips in plants. In this study, pectin methylesterase(PME) regulation of Al toxicity sensitivity and Al accumulation on cell walls were investigated in the root tips of two barley cultivars significantly different in Al resistance. Morin fluorescent staining showed that the fluorescence signal of root tips was much stronger in Al-sensitive cultivar 2000-2 than in Al-resistant Humai 16 after Al treatments, indicating that more Al was accumulated on the root tip of cv. 2000-2 than cv. Humai 16. Aluminon spectrophotometric assay further confirmed that the Al content in primary root tips was significantly higher in the Al-sensitive cultivar than in the Al-resistant one (ttest, p<0.05 or 0.01). Compared with individual controls, a significant increase of PME activity in root tips was observed in cv. 2000-2 after 4 h Al treatments, but after 24 h Al treatments, its PME activity significantly decreased. However, in cv. Humai 16, the significant alteration of PME activity was not observed over A1 treatments. These data together demonstrate that there exists a close correlation between Al accumulation and the change in PME activity on cell walls of the root tip, and therefore PME activity is involved in the regulation of Al sensitivity in the root tips of barley.%利用大麦耐铝品种和敏感品种来分析根尖果胶甲基酯酶(PME)在大麦铝毒敏感性中的调控作用.通过对耐铝性差异极其显著的2个大麦明品种2000-2与沪麦16经铝处理后的Morin荧光检测,观察到2000-2根尖荧光明显比沪麦16强,铝试剂比色法测定结果进一步表明,敏感品种根尖细胞壁上铝积累量比耐铝品种高,达到极显著差异(p<0.05或0.01).对根尖PME活性分析结果表明,与对照相比,铝处理4 h的2000-2根尖PME活性显著上升,但处理24 h后PME活性又显著下降;而沪麦16

  16. The COW1 locus of arabidopsis acts after RHD2, and in parallel with RHD3 and TIP1, to determine the shape, rate of elongation, and number of root hairs produced from each site of hair formation.

    Science.gov (United States)

    Grierson, C S; Roberts, K; Feldmann, K A; Dolan, L

    1997-11-01

    Two recessive mutant alleles at CAN OF WORMS1 (COW1), a new locus involved in root hair morphogenesis, have been identified in Arabidopsis thaliana L. Heynh. Root hairs on Cow1- mutants are short and wide and occasionally formed as pairs at a single site of hair formation. The COW1 locus maps to chromosome 4. Root hairs on Cow1- plants form in the usual positions, suggesting that the phenotype is not the result of abnormal positional signals. Root hairs on Cow1- roots begin hair formation normally, forming a small bulge, or root hair initiation site, of normal size and shape and in the usual position on the hair-forming cell. However, when Cow1- root hairs start to elongate by tip growth, abnormalities in the shape and elongation rate of the hairs become apparent. Genetic evidence from double-mutant analysis of cow1-1 and other loci involved in root hair development supports our conclusion that COW1 is required during root hair elongation.

  17. Effects of Lead on the Morphology and Structure of the Nucleolus in the Root Tip Meristematic Cells of Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Ze Jiang

    2014-07-01

    Full Text Available To study the toxic mechanisms of lead (Pb in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1–10 μM there were persistent nucleoli in some cells during mitosis, and at high concentration (100 μM many of the nucleolar organizing regions were localized on sticky chromosomes in metaphase and anaphase cells. Pb induced the release of particles containing argyrophilic proteins to be released from the nucleus into the cytoplasm. These proteins contained nucleophosmin and nucleolin. Pb also caused the extrusion of fibrillarin from the nucleus into the cytoplasm. Western blotting demonstrated the increased expression of these three major nucleolar proteins under Pb stress.

  18. Defining multiple, distinct, and shared spatiotemporal patterns of DNA replication and endoreduplication from 3D image analysis of developing maize (Zea mays L.) root tip nuclei.

    Science.gov (United States)

    Bass, Hank W; Hoffman, Gregg G; Lee, Tae-Jin; Wear, Emily E; Joseph, Stacey R; Allen, George C; Hanley-Bowdoin, Linda; Thompson, William F

    2015-11-01

    Spatiotemporal patterns of DNA replication have been described for yeast and many types of cultured animal cells, frequently after cell cycle arrest to aid in synchronization. However, patterns of DNA replication in nuclei from plants or naturally developing organs remain largely uncharacterized. Here we report findings from 3D quantitative analysis of DNA replication and endoreduplication in nuclei from pulse-labeled developing maize root tips. In both early and middle S phase nuclei, flow-sorted on the basis of DNA content, replicative labeling was widely distributed across euchromatic regions of the nucleoplasm. We did not observe the perinuclear or perinucleolar replicative labeling patterns characteristic of middle S phase in mammals. Instead, the early versus middle S phase patterns in maize could be distinguished cytologically by correlating two quantitative, continuous variables, replicative labeling and DAPI staining. Early S nuclei exhibited widely distributed euchromatic labeling preferentially localized to regions with weak DAPI signals. Middle S nuclei also exhibited widely distributed euchromatic labeling, but the label was preferentially localized to regions with strong DAPI signals. Highly condensed heterochromatin, including knobs, replicated during late S phase as previously reported. Similar spatiotemporal replication patterns were observed for both mitotic and endocycling maize nuclei. These results revealed that maize euchromatin exists as an intermingled mixture of two components distinguished by their condensation state and replication timing. These different patterns might reflect a previously described genome organization pattern, with "gene islands" mostly replicating during early S phase followed by most of the intergenic repetitive regions replicating during middle S phase.

  19. Effects of lead on the morphology and structure of the nucleolus in the root tip meristematic cells of Allium cepa L.

    Science.gov (United States)

    Jiang, Ze; Zhang, Huaning; Qin, Rong; Zou, Jinhua; Wang, Junran; Shi, Qiuyue; Jiang, Wusheng; Liu, Donghua

    2014-07-31

    To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1-10 μM) there were persistent nucleoli in some cells during mitosis, and at high concentration (100 μM) many of the nucleolar organizing regions were localized on sticky chromosomes in metaphase and anaphase cells. Pb induced the release of particles containing argyrophilic proteins to be released from the nucleus into the cytoplasm. These proteins contained nucleophosmin and nucleolin. Pb also caused the extrusion of fibrillarin from the nucleus into the cytoplasm. Western blotting demonstrated the increased expression of these three major nucleolar proteins under Pb stress.

  20. A Root Tip Squash Technique for Camellia semiserrata%广宁红花油茶根尖压片制作技术

    Institute of Scientific and Technical Information of China (English)

    李永泉; 陈清凤; 张应中; 丁晓纲; 蔡坚; 刘喻娟

    2012-01-01

    It is easier to acquire high yield of Camellia semiserrata if they are cultivated in their natural distribution area, such as Guangdong and Guangxi province. The yield character had a well potential of genetic improvement. The article summarizes a root tip squash technique for C. semiserrata. This technique could be applied on fluorescence in situ hybridization ( FISH) study and it is easy to carry out, time saving and has better effect than traditional technique. It could also be applied on cytological studies, chromosome engineering and analysis of plant genome as a basic technique.%广宁红花油茶在广东、广西等原生地种植容易获得高产,具有良好的遗传改良潜力.文章以广宁红花油茶为对象,探索了适用于荧光原位杂交技术中的染色体制片技术,并与传统的染色体压片制作技术进行比较,总结了一套节省时间、技术要求较低和效果较好的染色体根尖压片制作技术,可用于广宁红花油茶的细胞学研究,为开展分子染色体工程育种以及基因组分析奠定技术基础.

  1. On Applying the Micronucleus Technology of the Root Point of Broad Beans to Monitor the Water Quality in Duyun Rivers%蚕豆根尖微核技术监测剑江都匀市区河段水质

    Institute of Scientific and Technical Information of China (English)

    马媛; 龙俊; 吴莉莉

    2012-01-01

    本文利用蚕豆根尖微核技术监测剑江都匀市区河段水质的污染状况,测定6个断面水样的蚕豆根尖细胞微核千分率(MCN‰)及污染指数(PI),并进行F检测,结果表明,各断面水样均能引起微核率升高,桃溪园、枣园、水厂、彩虹桥、百子桥和文峰园断面的微核千分率分别为6.92%0、6.00‰、9.53%0、11.36‰、6.63%o、5.57%0,P1分别为2.06、1.79、2.83、3.38、1.97、1.66。按照污染指数划分标准,枣园、百子桥和文峰园断面的水质为轻度污染,桃溪园、水厂、彩虹桥断面水质为中度污染。%In this paper, the micronucleus of the root point of brand beans is applied to monitor the pollution situation of water quality in Duyun rivers. On the basis of a mensuration of the MCN%0 and PI of the cell in the root point of brand beans in six water sections and detection of F, the results show that water sample in each water section can cause the rise of MCN%0. The MCN%0 of the water section in Taoxiyuan, Zaoyuan, Water Factory, Rainbow Bridge, Baizi Bridge and Wenfengyuan section are as follows: 6.92 %0, 6.00 %0, 9.53 %0, 11.36 %0, 6.63 %0, 5.57 %0; PI are as follows: 2.06, 1.79, 2.83, 3.38, 1.97, 1.66. According to the PI standards, the water in Zaoyuan, Baizi Bridge and Wen- fengyuan sections is slightly polluted; that in Taoxiyuan, Water Factory and Rainbow Bridge sections is polluted moderately.

  2. Relative biological effectiveness of fission neutrons for producing micronuclei in the root-tip cells of onion seedlings after irradiation as dry seeds

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, W.; Ishikawa, Masayori; Hoshi, Masaharu [Hiroshima Univ. (Japan). Research Inst. for Radiation Biology and Medicine; Endo, Satoru [Hiroshima Univ., Higashi-Hiroshima (Japan). Graduate School of Engineering; Ikeda, Hideo [Hiroshima Univ., Higashi-Hiroshima (Japan). Faculty of Education

    2002-12-01

    The relative biological effectiveness (RBE) of mixed neutron and gamma-ray radiation emitted at a {sup 252}Cf source at the Research Institute for Radiation Biology and Medicine, Hiroshima University, compared with {sup 60}Co gamma-ray radiation was determined. The tissue-absorbed dose contribution of the accompanying gamma radiation was about 35.7% to the total tissue-absorbed dose from the {sup 252}Cf mixed radiation. The {sup 252}Cf mixed radiation and {sup 60}Co gamma rays produced approximate linear changes in the frequency of micronuclei induced in root-tip cells of Allium cepa L. onion seedlings after irradiation as dry dormant seeds with varying absorbed doses in onion seeds. Therefore, the RBE for radiation-induced micronuclei was calculated as the ratio of the slopes for the {sup 252}Cf mixed radiation and the {sup 60}Co gamma rays. The deduced RBE value of {sup 252}Cf mixed radiation of {sup 60}Co gamma rays to induce micronuclei in dry dormant onion seed cells was about 90.5{+-}3.6 ({+-}1{sigma}); the RBE of neutrons from the {sup 252}Cf mixed radiation was about 150{+-}6 ({+-}1{sigma}). Furthermore, the sensitivity ratio of the induction rate of micronuclei in dry dormant seeds to that in seedlings by neutrons from {sup 252}Cf mixed radiation was significantly different from that by {sup 60}Co gamma rays. From these results, we concluded that the repair efficiency of DNA damage induced by neutrons may be different from that by gamma rays. (author)

  3. 45S rDNA regions are chromosome fragile sites expressed as gaps in vitro on metaphase chromosomes of root-tip meristematic cells in Lolium spp.

    Directory of Open Access Journals (Sweden)

    Jing Huang

    Full Text Available BACKGROUND: In humans, chromosome fragile sites are regions that are especially prone to forming non-staining gaps, constrictions or breaks in one or both of the chromatids on metaphase chromosomes either spontaneously or following partial inhibition of DNA synthesis and have been well identified. So far, no plant chromosome fragile sites similar to those in human chromosomes have been reported. METHODS AND RESULTS: During the course of cytological mapping of rDNA on ryegrass chromosomes, we found that the number of chromosomes plus chromosome fragments was often more than the expected 14 in most cells for Lolium perenne L. cv. Player by close cytological examination using a routine chromosome preparation procedure. Further fluorescent in situ hybridization (FISH using 45S rDNA as a probe indicated that the root-tip cells having more than a 14-chromosome plus chromosome fragment count were a result of chromosome breakage or gap formation in vitro (referred to as chromosome lesions at 45S rDNA sites, and 86% of the cells exhibited chromosome breaks or gaps and all occurred at the sites of 45S rDNA in Lolium perenne L. cv. Player, as well as in L. multiflorum Lam. cv. Top One. Chromatin depletion or decondensation occurred at various locations within the 45S rDNA regions, suggesting heterogeneity of lesions of 45S rDNA sites with respect to their position within the rDNA region. CONCLUSIONS: The chromosome lesions observed in this study are very similar cytologically to that of fragile sites observed in human chromosomes, and thus we conclude that the high frequency of chromosome lesions in vitro in Lolium species is the result of the expression of 45S rDNA fragile sites. Possible causes for the spontaneous expression of fragile sites and their potential biological significance are discussed.

  4. 铝胁迫对豇豆幼苗根尖抗氧化系统的影响%Antioxidant Enzyme Activities in Root Tips of Vigna unguiculata L.Seedlings under Aluminum Stress

    Institute of Scientific and Technical Information of China (English)

    于力; 孙锦; 郭世荣; 阎君; 朱为民

    2012-01-01

    The ROS metabolize and root growth of Vigna unguiculata L. cultivar 'T6' (Al-tolerant) and 'S3'(Al-sensitive) root tip was measured to analyze the relative between Al tolerance and ROS metabolize. The results show that: (1) The root length of ' T6 ' and ' S3 ' was inhibited with the increase of Al, the decrease of 'S3' was larger than that of 'T6'. (2)The superoxide anion radical (O2- ),H2O2 content,MDA content and plasma-membrane permeability of ' T6' and 'S3' root tip increase significantly by Al increase from 0 to 500 μmol · L1,but 'S3' made more increase than that of 'T6' (3)The SOD,POD,CAT,APX, GR, AsA,GSH of 'T6' and 'S3' root tip increased after exposure to 0 to 500 μmol · L-1 Al. The increase range of SOD of 'S3' root tip was higher than that of 'T6' ,but increase range of POD,CAT,APX of 'S3' root tip were lower than that of 'T6'. We presume that 'S3' root tip accumulated more ROS and increased the oxidative stress,then result in the inhibition of root growth.%选用豇豆铝敏感品种‘S3’和耐铝品种‘T6’为试验材料,研究不同耐铝性豇豆根系伸长和根尖活性氧代谢变化的差异,探讨铝胁迫下不同耐铝性豇豆在活性氧代谢上的差异及其与豇豆耐铝性的关系.结果表明:(1)随着铝处理浓度的增加,2个品种根系伸长均受到抑制,且‘S3’受到的抑制程度大于‘T6’.(2)随着处理铝浓度的升高,2个豇豆品种的根尖O2-·产生速率、H2O2含量、MDA含量及质膜透性都显著增加,且‘S3,的增加幅度大于‘T6’.(3)铝胁迫处理下,2个豇豆品种幼苗根尖超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性都有所上升,其中铝敏感品种‘S3’的SOD活性上升幅度比耐铝品种‘T6’高,而POD、CAT、APX的上升幅度比耐铝品种‘T6’低.研究认为,铝胁迫下铝敏感品种‘S3,内活性氧物质过量积累

  5. CPAP Tips

    Science.gov (United States)

    ... Queue Queue __count__/__total__ Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Subscribe Subscribed Unsubscribe 15, ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

  6. Melatonin promotes adventitious root regeneration in in vitro shoot tip explants of the commercial sweet cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and MxM 60 (P. avium × P. mahaleb).

    Science.gov (United States)

    Sarropoulou, Virginia N; Therios, Ioannis N; Dimassi-Theriou, Kortessa N

    2012-01-01

    The objectives of this study were to test the effects of melatonin (N-acetyl-5-methoxytryptamine), a natural compound of edible plants on the rooting of certain commercial sweet cherry rootstocks. Shoot tip explants from previous in vitro cultures of the cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and M × M 60 (P. avium × P. mahaleb) were included in the experiment. The effect of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) alone or in combination with melatonin was tested concerning their rooting potential. Seven concentrations of melatonin (0, 0.05, 0.1, 0.5, 1, 5, and 10 μM) alone or in combination with 5.71 μM of IAA or 4.92 μM of IBA were tested. For each rootstock, 21 treatments were included. The explants were grown in glass tubes containing 10 mL of substrate. The parameters measured include rooting percentage, number of roots per rooted explant, root length, and callus formation. The data presented in this study show that melatonin has a rooting promoting effect at a low concentration but a growth inhibitory effect at high concentrations. In the absence of auxin, 1 μM melatonin had auxinic response concerning the number and length of roots, but 10 μM melatonin was inhibitory to rooting in all the tested rootstocks. The final conclusion of this experiment is that exogenously applied melatonin acted as a rooting promoter and its action was similar to that of IAA.

  7. Numerical Simulation on the Effect of Tip Clearance Size on Unsteadiness in Tip Clearance Flow

    Institute of Scientific and Technical Information of China (English)

    Juan Du; Feng Lin; Hongwu Zhang; Jingyi Chen

    2008-01-01

    Unsteadiness of tip clearance flow with three different tip clearance sizes is numerically investigated in this paper. NASA Rotor 67 is chosen as the computational model. It is found that among all the simulated cases, the un-steadiness exists when the size of the tip clearance is equal to or larger than design tip clearance size. The relative total pressure coefficient contours indicate that region of influence by tip leakage flow augments with the increase of tip clearance size at a fixed mass flow rate. Root Mean Square contours of static pressure distribution in the rotor tip region are provided to illustrate that for design tip clearance (1.1% tip chord) the strongest fluctuating region is located on pressure side of blade near leading edge, while for the larger tip clearance (2.2% tip chord), it is in the region of the interaction between the shock wave and the tip leakage flow.

  8. Investigations of Interaction of the Main Flow with Root and Tip Leakage Flows in an Axial Turbine Stage by Means of a Source/Sink Approach for a 3D Navier-Stokes Solver

    Institute of Scientific and Technical Information of China (English)

    Piotr Lampart; Andrzej Gardzilewicz; Sergey Yershov; Andrey Rusanov

    2001-01-01

    The effect of interaction of the main flow with root and tip leakage flows on the performance of an high pressure (HP) stage of an impulse turbine is studied numerically. The flow in blade-to-blade channels and axial gaps is computed with the aid of a 3D Navier-Stokes solver FlowER. The numerical scheme is modified to include the some/sink-type boundary conditions in places at the endwalls referring to design locations of injection of leakage and windage flows into, or extract from, the blade-to-blade passage. The turbine stage is computed in three configurations. First, computations are made without tip leakage and windage flows with source/sink slots closed.Second, tip leakage slots are open. Third, both tip leakage and windage flow slots are open, and the obtained flow characteristics including kinetic energy losses in the stage are compared so as to estimate the interaction of the main and leakage flows.

  9. Effect of water deficiency on anatomical structure of codex in root hair zone of maize root tip%水分亏缺对玉米根毛区皮层解剖结构的影响

    Institute of Scientific and Technical Information of China (English)

    于涛; 李万春; 汪李宏; 岳文俊; 马旭凤; 姚雅琴; 张富仓

    2011-01-01

    【Objective】 The research was to study the effect of water deficiency on anatomical structure of codex in maize root hair zone for drought resistance mechanism.【Method】 Taking Gaonong 901 maize which has certain drought resistance in a pot experiment as four groups named control,light deficiency,moderate deficiency,severe deficiency with water treatments:75%-85% of field capacity(CK),65%-75% of field capacity(LS),55%-65% of field capacity(MS),and 45%-55% of field capacity(SS).Tissues of roots which were 10 cm distance from root tips prepared emgedded in epoxy resins were cut into half thin section for optical microscope.With green and the counterstain safranin,armour aniline blue and fluorescent dyes,the changes of cortical cell and casparian band were found through observation under Olympus BX51 microscope and calculation by image pro plus 6.0.【Result】 With increasing water deficiency,codex parenchyma cells were irregularly arranged and width of codex in root hair zone of maize seedling and jointing got thinner.Both in seedling and jointing stage,the length of endodermis in root hair zone decreased unconspicuously,and the width of endodermis changed obviously.Comparatively,the endodermis in seedling changed more obviously than that in jointing,which caused by mature casparian band enhanced mechanical strength of endodermis.Fluorescence observations showed that casparian band of axial walls of endodermis thickened on seedling stage with light deficiency.Both axial and inner tangential walls of casparian band of endodermis thickened more obviously at jointing stage with light and moderate deficiency.Endodermis which had less modified structure deformated obviously with severe deficiency.【Conclusion】 The structure of codex in root hair zone of maize at seedling was more sensitive than at jointing with water deficiency.The tolerance of roots to proper water deficit may be increased by changes such as width of codex and ligno

  10. Hairy roots are more sensitive to auxin than normal roots

    OpenAIRE

    Shen, Wen Hui; Petit, Annik; Guern, Jean; Tempé, Jacques

    1988-01-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exo...

  11. Genotoxic effects and induction of phytochelatins in the presence of cadmium in Vicia faba roots.

    Science.gov (United States)

    Béraud, Eric; Cotelle, Sylvie; Leroy, Pierre; Férard, Jean-François

    2007-10-01

    This study investigates different effects in roots of Vicia faba (broad bean) after exposure to cadmium. Genotoxic effects were assessed by use of the well-known Vicia root tip micronucleus assay. Cytotoxic effects were evaluated by determining the mitotic index in root tip cells. Finally, molecular induction mechanisms were evaluated by measuring phytochelatins with HPLC. After hydroponical exposure of V. faba roots to a range of cadmium concentrations and during different exposure times, the results of this approach showed large variations, according to the endpoint measured: after 48 h of exposure, genotoxic effects were found between 7.5 x 10(-8) and 5 x 10(-7)M CdCl(2), and cytotoxic effects were observed between 2.5 x 10(-7) and 5 x 10(-7)M CdCl(2). Statistically significant phytochelatin (PC) concentrations were measured at >or=10(-6)M CdCl(2) for PC(2), and at >or=10(-5)M CdCl(2) for PC3 and PC4.

  12. Copper-induced root growth inhibition of Allium cepa var. agrogarum L. involves disturbances in cell division and DNA damage.

    Science.gov (United States)

    Qin, Rong; Wang, Congyue; Chen, Da; Björn, Lars O; Li, Shaoshan

    2015-05-01

    Copper (Cu) is considered to be an indispensable microelement for plants. Excessive Cu, however, is toxic and disturbs several processes in the plant. The present study addressed the effects of ionic Cu (2.0 µM and 8.0 µM) on mitosis, the microtubule cytoskeleton, and DNA in root tip cells of Allium cepa var. agrogarum L. to better understand Cu toxicity on plant root systems. The results indicated that Cu accumulated in roots and that root growth was inhibited dramatically in Cu treatment groups. Chromosomal aberrations (for example, C-mitosis, chromosome bridges, chromosome stickiness, and micronucleus) were observed, and the mitotic index decreased during Cu treatments at different concentrations. Microtubules were one of the target sites of Cu toxicity in root tip meristematic cells, and Cu exposure substantially impaired microtubule arrangements. The content of α-tubulin decreased following 36 h of exposure to 2.0 µM or 8.0 µM of Cu in comparison with the control group. Copper increased DNA damage and suppressed cell cycle progression. The above toxic effects became more serious with increasing Cu concentration and prolonged exposure time.

  13. Hairy roots are more sensitive to auxin than normal roots

    Science.gov (United States)

    Shen, Wen Hui; Petit, Annik; Guern, Jean; Tempé, Jacques

    1988-01-01

    Responses to auxin of Lotus corniculatus root tips or protoplasts transformed by Agrobacterium rhizogenes strains 15834 and 8196 were compared to those of their normal counterparts. Three different types of experiments were performed, involving long-term, medium-term, or short-term responses to a synthetic auxin, 1-naphthaleneacetic acid. Root tip elongation, proton excretion by root tips, and transmembrane electrical potential difference of root protoplasts were measured as a function of exogenous auxin concentration. The sensitivity of hairy root tips or protoplasts to exogenous auxin was found to be 100-1000 times higher than that of untransformed material. PMID:16593928

  14. Tipping Point

    Medline Plus

    Full Text Available ... OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point ... 24 hours a day. For young children whose home is a playground, it’s the best way to ...

  15. Tipping Point

    Medline Plus

    Full Text Available ... Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head ... see news reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The ...

  16. CPAP Tips

    Medline Plus

    Full Text Available ... navigation Sign in Search Loading... Close Yeah, keep it Undo Close This video is unavailable. Watch Queue ... trial of YouTube Red. Working... No thanks Try it free Find out why Close CPAP Tips from ...

  17. Tipping Point

    Medline Plus

    Full Text Available ... of a large television falling from tipping furniture can be staggering. A 50 lb. TV falls with ... story of a building. That kind of impact can kill a child or cause severe injuries. About ...

  18. Base to Tip and Long-Distance Transport of Sodium in the Root of Common Reed [Phragmites australis (Cav.) Trin. ex Steud.] at Steady State Under Constant High-Salt Conditions.

    Science.gov (United States)

    Fujimaki, Shu; Maruyama, Teppei; Suzui, Nobuo; Kawachi, Naoki; Miwa, Eitaro; Higuchi, Kyoko

    2015-05-01

    We analyzed the directions and rates of translocation of sodium ions (Na(+)) within tissues of a salt-tolerant plant, common reed [Phragmites australis (Cav.) Trin. ex Steud.], and a salt-sensitive plant, rice (Oryza sativa L.), under constant high-salt conditions using radioactive (22)Na tracer and a positron-emitting tracer imaging system (PETIS). First, the test plants were incubated in a nutrient solution containing 50 mM NaCl and a trace level of (22)Na for 24 h (feeding step). Then the original solution was replaced with a fresh solution containing 50 mM NaCl but no (22)Na, in which the test plants remained for >48 h (chase step). Non-invasive dynamic visualization of (22)Na distribution in the test plants was conducted during feeding and chase steps with PETIS. Our results revealed that (22)Na was absorbed in the roots of common reed, but not transported to the upper shoot beyond the shoot base. During the chase step, a basal to distal movement of (22)Na was detected within the root tissue over >5 cm with a velocity of approximately 0.5 cm h(-1). On the other hand, (22)Na that was absorbed in the roots of rice was continuously translocated to and accumulated in the whole shoot. We concluded that the basal roots and the shoot base of common reed have constitutive functions of Na(+) exclusion only in the direction of root tips, even under constant high-salt conditions. This function apparently may contribute to the low Na(+) concentration in the upper shoot and high salt tolerance of common reed.

  19. Allelopathic potential of the invasive plant Ageratum conyzoides with Vicia-micronucleus test%利用蚕豆根尖微核试验研究入侵植物胜红蓟的化感作用潜力

    Institute of Scientific and Technical Information of China (English)

    吴亚娟; 何兴金

    2012-01-01

    [Objective]To study the allelopathic potential of the invasive plant Ageratum conyzoides Linn. [Method] The allopathic effects of aqueous extracts of leaf, stem, flower and ground part of A. Conyzoides were studied by using View-micronucleus test. [Result]The results showed that the aqueous extracts had genetic toxicity to Vi-cia faba root tip cells. The aqueous extracts of leaf, stem, flower and ground part had the mitotic index decreased, the micronucleus frequency increased, and aberrant chromosomes such as micronucleus, chromosome bridge and chromosome ring. These effects were concentration-dependent. The allelopathic effects of aqueous extracts increased in the following order: flower, stem, leaf and ground part. Compared with the ground part, the allelopathic potential of the three parts did not increase simply, but the role of leaf was strongest. [Conclusion] The leaf had the highest allelopathic potential.%[目的]研究入侵植物胜红蓟(Ageratum conyzoides Linn.)的化感作用潜力.[方法]运用蚕豆(Vicia fabaL)根尖细胞微核试验研究入侵植物胜红蓟叶、茎、花以及地上部分(除去根以外的植物体,下同)水浸提液的化感效应.[结果]胜红蓟水浸提液具有较强的遗传毒性.在叶、茎、花和地上部分水浸提液作用下,蚕豆根尖细胞有丝分裂指数下降,微核率升高,细胞中出现了微核、染色体桥、染色体环等多种染色体畸变,胜红蓟水浸提液对蚕豆根尖的影响存在显著的浓度效应.胜红蓟叶、茎、花和地上部分的整体效应为叶>茎>花>地上部分,与地上部分相比三部位之间的化感作用潜力不存在简单加和作用,但仍以叶片效应最强.[结论]叶片具有最高的化感作用潜力.

  20. Role of micronucleus in oral exfoliative cytology.

    Science.gov (United States)

    Shashikala, R; Indira, A P; Manjunath, G S; Rao, K Arathi; Akshatha, B K

    2015-08-01

    In the last few years, the interest for oral cytology as a diagnostic and prognostic methodology, for monitoring patients in oral potentially malignant disorders and oral cancer has re-emerged substantially. In 1983, buccal mucosal micronuclei assay was first proposed to evaluate genetic instability. There are biomarkers that predict if a potentially malignant disorder is likely to develop into an aggressive tumor. These genotoxic and carcinogenic chemicals have been reported to be potent clastogenic and mutagenic agents which are thought to be responsible for the induction of chromatid/chromosomal aberrations resulting in the production of micronuclei. Various studies have concluded that the gradual increase in micronucleus (MN) counts from normal oral mucosa to potentially malignant disorders to oral carcinoma suggested a link of this biomarker with neoplastic progression. MN scoring can be used as a biomarker to identify different preneoplastic conditions much earlier than the manifestations of clinical features and might specifically be exploited in the screening of high-risk population for a specific cancer. Hence, it can be used as a screening prognostic and educational tool in community centers of oral cancer.

  1. CPAP Tips

    Medline Plus

    Full Text Available ... Published on Dec 12, 2012 Do you have sleep apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely and effectively ...

  2. CPAP Tips

    Medline Plus

    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ... Duration: 3:42. Southern California Pulmonary and Sleep Disorders Medical Center 72,447 views 3:42 The ...

  3. Prevention Tips

    Science.gov (United States)

    ... Prevention Tips Post-Exposure Treatment  Blood Tests and Diagnosis Hepatitis B Blood Tests Understanding Your Hepatitis B Test Results ... acupuncture Home About Us Quick Links What Is Hepatitis B? Prevention & Diagnosis Treatment & Management Resources & Support Research & Programs News & Events ...

  4. CPAP Tips

    Medline Plus

    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ... Copyright Creators Advertise Developers +YouTube Terms Privacy Policy & Safety Send feedback Test new features Loading... Working... Sign ...

  5. The clinical effect of MTA in root tip reverse filling treatment for external apical root resorption of permanent anterior teeth%MTA用于根尖倒充填治疗恒前牙根尖外吸收的临床疗效观察

    Institute of Scientific and Technical Information of China (English)

    马列娜; 杨丽

    2016-01-01

    Objective:To explore the clinical effect of MTA in root tip reverse filling treatment for external apical root resorption of permanent anterior teeth.Methods:78 patients with periapical disease were selected.They were randomly divided into the experimental group and the control group with 39 cases in each.The experimental group was treated by MTA in root tip reverse filling.The control group was treated with silver mercury.We compared the treatment effect of two groups.Results:In the experimental group,the apical closure and repair of lesions were significantly better than the control group(P<0.05).The treatment effective rate of the experimental group of 97.4% was significantly higher than 89.7% of the control group(P<0.05).Conclusion:The clinical effect of MTA in root tip reverse filling treatment for external apical root resorption of permanent anterior teeth was significant.%目的:探讨矿物三氧化物凝聚体(MTA)用于根尖倒充填治疗恒前牙根尖外吸收的临床效果。方法:收治根尖周病患者78例,随机分为试验组和对照组各39例,试验组行MTA术进行根尖倒充填,对照组给予银汞合金治疗,比较两组的治疗效果。结果:试验组根尖封闭状况及病损区修复情况明显优于对照组(P<0.05)。试验组治疗有效率97.4%,明显高于对照组的89.7%(P<0.05)。结论:MTA用于根尖倒充填治疗恒前牙根尖外吸收的临床疗效显著。

  6. Spatial and temporal regulation of nucleating sites for arrays of cortical microtubules in root tip cells of the water fern Azolla pinnata.

    Science.gov (United States)

    Gunning, B S

    1980-12-01

    Root primordia of the water fern Azolla pinnata were examined by conventional and high voltage electron microscopy to extend previous evidence concerning the existence and behaviour of nucleating sites (NS) for microtubule arrays in the cortex of plant cells. Putative NS are visible as foci consisting of clusters of microtubules, a population of particles or vesicles and associated dense material. They are concentrated along the edges of the cells but become conspicuous only when cortical arrays are being generated, i.e. at the early post-cytokinesis phase when interphase arrays are being reinstated and when pre-prophase bands are forming. Examples of temporal regulation during the cell cycle are documented. The predictable anatomy of the Azolla root allows specified edges of cells to be examined in successive cell cycles. The NS first appear at a newly generated edge (where one of the walls that meet at the edge is derived from a new cell plate) and reappear after cytokinesis at that same edge in later cycles, irrespective of the plane of division, when it is no longer newly formed but one, two or more cell cycles old. All of the edges of a cell, whether radial, longitudinal, or tangential, have the potential to develop NS but a strong element of selectivity appears to be imposed. The possible role of the system of NS in microtubule development and overall morphogenesis in the root is discussed.

  7. The effects of nano-TiO{sub 2} on seed germination, development and mitosis of root tip cells of Vicia narbonensis L. and Zea mays L

    Energy Technology Data Exchange (ETDEWEB)

    Ruffini Castiglione, Monica, E-mail: mruffini@biologia.unipi.it [University of Pisa, Department of Biology (Italy); Giorgetti, Lucia; Geri, Chiara [Institute of Agricultural Biology and Biotechnology (IBBA/CNR), UOS Pisa (Italy); Cremonini, Roberto [University of Pisa, Department of Biology (Italy)

    2011-06-15

    This study aimed to provide new information about phyto-toxicology of nano-TiO{sub 2} on plant systems. To contribute to the evaluation of the potential harmful effects of the nanoparticles on monocots and dicots we considered their effects on seed germination and root elongation applying a concentration range from 0.2 to 4.0 Per-Mille-Sign in the plants Zea mays L. and Vicia narbonensis L. Moreover, we achieved a genotoxicity study at cytological level in root meristems by means of traditional cytogenetic approach, to evidence possible alterations in mitotic activity, chromosomal aberrations, and micronuclei release. From these analyses it comes out that nano-TiO{sub 2} particles, after short-term exposure and under our experimental conditions, delayed germination progression for the first 24 h in both materials. Root elongation was affected only after treatment with the higher nano-TiO{sub 2} concentration. Further significant effects were detected showing mitotic index reduction and concentration-dependent increase in the aberration emergence that evidenced a nano-TiO{sub 2}-induced genotoxic effect for both species.

  8. NO和H2O2诱导大豆根尖和边缘细胞耐铝反应的作用%Effects of nitric oxide and hydrogen peroxide on induction of a defense response in the root tips and root border cells of soybean plants to Al toxicity

    Institute of Scientific and Technical Information of China (English)

    王芳妹; 蔡妙珍; 张淑娜; 王宁; 李华飞; 胡雪娜; 虞舒航

    2011-01-01

    Aims Nitric oxide (NO) and hydrogen peroxide (H2O2) function as signaling molecules in plants. A role for NO and H2O2 in the regulation of many abiotic stress responses, including drought, salt, heat, heavy metal and Al stresses, has been proposed. Our objective was to investigate (a) the Al-dependent accumulation of endogenous NO and H2O2 in root tips and (b) the role of exogenous NO and H2O2 in alleviating Al toxicity in root tips and root border cells (RBCs).Methods Seedlings of soybean (Glycine max) 'Zhechun No. 3' were divided into two groups for hydroponic and aeroponic cultured experiments. In order to investigate the response of endogenous NO and H2O2 in root tips to 50 umol·L-1Al, we determined root elongation, Al content in root apexes, endogenous NO and H2O2 content and their location in hydroponic cultured experiments. In the aeroponic culture experiments, seedlings were pretreated with exogenous NO and H2O2, then RBCs viability as well as the indicators in hydroponic cultured experiments were tested to clarify the role of exogenous NO and H2O2 on alleviating Al toxicity in root tips and RBCs. Important findings Al inhibited root elongation, increased Al content in root apexes and induced endogenous NO and H2O2 accumulation with the hydroponic culture. Results of the aeroponic experiments demonstrated that both 0.25 mmol·L-1 NO donor sodium nitroprusside (SNP) and 0.1 mmol·L-1 H2O2 alleviated the inhibitory effect of Al, decreased Al accumulation in root tips and enhanced RBCs viability. The 0.05 mmol·L-1 NO scavenger cPTIO (carboxy-PTIO) and 150 U·mL-1 H2O2 scavenger CAT (catalase) reversed the alleviating effect. Furthermore, the results indicated that exogenous NO promoted the accumulation of H2O2 in root apexes, while exogenous H2O2 did not significantly affect NO content in root apexes. All of these results suggested that the rise of NO and H2O2 were in accordance with defense response in root apexes and RBCs to Al toxicity in soybean, and

  9. Validation of the micronucleus-centromere assay for biological dosimetry

    Directory of Open Access Journals (Sweden)

    Wojcik A.

    2000-01-01

    Full Text Available The micronucleus assay is frequently used for purposes of biological dosimetry. Due to high interindividual variability in the spontaneous frequency of micronuclei, its sensitivity in the low dose region is poor. It has been suggested that this problem can be mitigated by selectively analyzing the frequency of those micronuclei which contain only acentric fragments. Using a pan-centromeric FISH probe we have studied the dose dependence of micronuclei with centromeres in peripheral lymphocytes of human donors. In contrast to previous publications, our approach is based on determining the relative frequency of micronuclei with and without centromeric signals. Our results confirm previous observations that in the low dose range of ionizing radiation, the micronucleus-centromere assay is more sensitive than the conventional micronucleus test.

  10. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  11. A nonsymbiotic root hair tip growth phenotype in NORK-mutated legumes: implications for nodulation factor-induced signaling and formation of a multifaceted root hair pocket for bacteria

    NARCIS (Netherlands)

    Esseling, J.J.; Lhuissier, F.G.P.; Emons, A.M.C.

    2004-01-01

    The Medicago truncatula Does not Make Infections (DMI2) mutant is mutated in the nodulation receptor-like kinase, NORK. Here, we report that NORK-mutated legumes of three species show an enhanced touch response to experimental handling, which results in a nonsymbiotic root hair phenotype. When care

  12. Tonoplast aquaporins facilitate lateral root emergence

    DEFF Research Database (Denmark)

    Reinhardt, Hagen; Hachez, Charles; Bienert, Manuela Désirée

    2016-01-01

    that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip...... could be fully rescued by expressing AtTIP2;1 under its native promoter. We conclude that TIP isoforms allow the spatial and temporal fine-tuning of cellular water transport, which is critically required during the highly regulated process of LRP morphogenesis and emergence....

  13. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Science.gov (United States)

    2010-07-01

    ... cytogenetics tests: Micronucleus assay. 798.5395 Section 798.5395 Protection of Environment ENVIRONMENTAL... Genetic Toxicity § 798.5395 In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay. (a) Purpose. The micronucleus test is a mammalian in vivo test which detects damage of the chromosomes...

  14. Elevated CO2 and O3 effects on ectomycorrhizal fungal root tip communities in consideration of a post-agricultural soil nutrient gradient legacy.

    Science.gov (United States)

    Andrew, Carrie; Lilleskov, Erik A

    2014-11-01

    Despite the critical role of EMF in nutrient and carbon (C) dynamics, combined effects of global atmospheric pollutants on ectomycorrhizal fungi (EMF) are unclear. Here, we present research on EMF root-level community responses to elevated CO2 and O3. We discovered that belowground EMF community richness and similarity were both negatively affected by CO2 and O3, but the effects of CO2 and O3 on EMF communities were contingent on a site soil pH and cation availability gradient. These results contrast with our previous work showing a strong direct effect of CO2 and O3 on sporocarp community dynamics and production. We discuss the possible role of carbon demand and allocation by EMF taxa in the discrepancy of these results. EMF communities were structured by a legacy of spatially defined soil properties, changing atmospheric chemistry and temporal dynamics. It is therefore necessary to understand global change impacts across multiple environmental gradients and spatiotemporal scales.

  15. Genotoxic effects of the carbamate insecticide Pirimor-50® in Vicia faba root tip meristems and human lymphocyte culture after direct application and treatment with its metabolic extracts.

    Science.gov (United States)

    Valencia-Quintana, Rafael; Gómez-Arroyo, Sandra; Sánchez-Alarcón, Juana; Milić, Mirta; Olivares, José Luis Gómez; Waliszewski, Stefan M; Cortés-Eslava, Josefina; Villalobos-Pietrini, Rafael; Calderón-Segura, María Elena

    2016-12-01

    The aim of the study was to evaluate genotoxic effects of Pirimor-50®, a pirimicarb-based formulation (50 % active ingredient), in human lymphocyte cultures and Vicia faba root meristems. Furthermore, the objective was to examine a combined influence of insecticide treatment with mammalian microsomal S9 and vegetal S10 metabolic fractions or S10 mix metabolic transformation extracts (after Vicia faba primary roots treatment with Pirimor-50®). We used sister chromatid exchange assay-SCE and measured cell cycle progression and proliferation (proportion of M1-M3 metaphases and replication index ratio-RI). Two processes were used for plant promutagen activation: in vivo activation-Pirimor-50® was applied for 4 h to the plant and then S10 mix was added to lymphocytes; and, in vitro activation-lymphocytes were treated with Pirimor-50® and S10 or S9 for 2 h. Direct treatment induced significantly higher SCE frequencies in meristems at 0.01 mg mL-1. In lymphocytes, significantly higher SCE was at 1 mg mL-1 with decrease in RI and M1-M3 metaphase proportions at 0.5 mg mL-1 and cell division stop at 2.5 mg mL1. S10 mix lymphocyte treatment showed significantly elevated SCE values at 2-2.5 mg mL-1, with cell death at 3 mg mL-1. Lymphocyte treatment with Pirimor-50® together with S9 or S10 showed slightly elevated SCE frequency but had a significant influence on RI decrease, with lowest values in S9 treatment. Since no data are available on the genotoxicity of Pirimor-50®, this study is one of the first to evaluate and compare its direct effect in two bioassays, animal and vegetal, and also the effect of plant and animal metabolism on its genotoxic potential.

  16. What Can a Micronucleus Teach? Learning about Environmental Mutagenesis

    Science.gov (United States)

    Linde, Ana R.; Garcia-Vazquez, Eva

    2009-01-01

    The micronucleus test is widely employed in environmental health research. It can also be an excellent tool for learning important concepts in environmental health. In this article we present an inquiry-based laboratory exercise where students explore several theoretical and practical aspects of environmental mutagenesis employing the micronucleus…

  17. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true TSCA mammalian erythrocyte micronucleus test. 799.9539 Section 799.9539 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... strains of young healthy animals should be employed. At the commencement of the study, the...

  18. Role of the micronucleus in stomatogenesis in sexual reproduction of Paramecium tetraurelia: laser microbeam irradiation of the micronucleus

    Energy Technology Data Exchange (ETDEWEB)

    Tam Laiwa; Ng, S.F.

    1986-12-01

    Fifteen amicronucleate cell lines and 22 cell lines with defective micronuclei were obtained following selective laser microbeam irradiation of the micronucleus. The amicronucleate cell lines showed reduced growth rate and formed abnormal oral apparatuses in asexual reproduction, and failed to produce any oral apparatus in autogamy. The 22 cell lines with defective micronucleus exhibited various abnormalities of the oral apparatus newly formed during autogamy. These abnormalities included the arrest of membranelle assembly, reduction in the length of the buccal cavity and oral membranelles, disruption of the organization of the membranelles, quadrulation of the dorsal peniculus, and failure of addition of membranellar basal body rows. Hence the micronucleus plays multiple roles in sexual stomatogenesis. Our results agree with the notion that the micronucleus acts during a critical period between the second meiotic division and up to the formation of the zygotic nucleus to control the early stage of oral membranelle assembly. Laser microbeam irradiation might have created recessive mutations and/or chromosomal aberrations, which were expressed during this critical period with the formation of abnormal postmeiotic nuclei.

  19. Rodent Bone Marrow Micronucleus Assay. Test Substance: Solvent Yellow 33 2-(2-Quinolyl)-1,3-indandione

    Science.gov (United States)

    2011-01-18

    COVERED 4. TITLE AND SUBTITLE Rodent Bone Marrow Micronucleus Assay Test Substance, Solvent Yellow 33 2-(2-Quinolyl)-1,3-indandione 5a. CONTRACT...Assay (Negative Control) 48 hours: Body Weights, Dosing Data, Clinical Observations, and Micronucleus Scoring Data Micronucleus Assay ( Test Substance...2000 mg/kg Body Weight) 24 hours: Body Weights, Dosing Data, Clinical Observations, and Micronucleus Scoring Data Micronucleus Assay ( Test Substance

  20. Low dose genotoxicity of 4-bromo-n,n-diethyl-5,5- dimethyl-2,5-dihydro-1,2-oxaphosphol-2-amine 2-oxide in mice bone marrow cells and Allium cepa L. root tip cells

    Directory of Open Access Journals (Sweden)

    Kalcheva Vanya

    2009-01-01

    Full Text Available The chemistry of organophosphorus compounds is a subject of increasing interest and different new compounds have been synthesized. There are data that some known organophosphates are mutagens. Oxaphosphole derivatives possess biological activity and might influence proliferating cells. Bioassays are currently used in ecotoxicology to investigate the effects and mechanisms of action of new chemicals. To provide a broad coverage of the mutagenic potential of a chemical, information on different experimental test-systems is required. Genotoxicity assays are usually performed at high doses, but humans are exposed to most environmental chemicals at low doses. The objective of this study was to determine the genotoxicity of low doses (2.82x10-6 µg/kg and 2.82x10-9 µg/kg, corresponding to concentrations 10-12M and 10-15M of 4-bromo-N,N-diethyl- 5,5-dimethyl-2,5-dihydro-1,2-oxaphosphol-2-amine 2-oxide (Br-oxph in ICR mice bone marrow cells and Allium cepa L. root tip cells. Treatment with Br-oxph for 3 h produced alterations in the mitotic index in Allium cepa cells and induced chromosome aberrations in both test systems. These effects remained 48 h after the treatment. The data from the study showed the existence of cytotoxic and genotoxic effects of Br-oxph at tested doses.

  1. Micronucleus formation induced by dielectric barrier discharge plasma exposure in brain cancer cells

    Science.gov (United States)

    Kaushik, Nagendra K.; Uhm, Hansup; Ha Choi, Eun

    2012-02-01

    Induction of micronucleus formation (cytogenetic damage) in brain cancer cells upon exposure of dielectric barrier discharge plasma has been investigated. We have investigated the influence of exposure and incubation times on T98G brain cancer cells by using growth kinetic, clonogenic, and micronucleus formation assay. We found that micronucleus formation rate directly depends on the plasma exposure time. It is also shown that colony formation capacity of cells has been inhibited by the treatment of plasma at all doses. Cell death and micronucleus formation are shown to be significantly elevated by 120 and 240 s exposure of dielectric barrier discharge plasma.

  2. Probe tip heating assembly

    Science.gov (United States)

    Schmitz, Roger William; Oh, Yunje

    2016-10-25

    A heating assembly configured for use in mechanical testing at a scale of microns or less. The heating assembly includes a probe tip assembly configured for coupling with a transducer of the mechanical testing system. The probe tip assembly includes a probe tip heater system having a heating element, a probe tip coupled with the probe tip heater system, and a heater socket assembly. The heater socket assembly, in one example, includes a yoke and a heater interface that form a socket within the heater socket assembly. The probe tip heater system, coupled with the probe tip, is slidably received and clamped within the socket.

  3. Characterizing pathways by which gravitropic effectors could move from the root cap to the root of primary roots of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1989-01-01

    Plasmodesmata linking the root cap and root in primary roots Zea mays are restricted to approx. 400 protodermal cells bordering approx. 110000 microns2 of the calyptrogen of the root cap. This area is less than 10% of the cross-sectional area of the root-tip at the cap junction. Therefore, gravitropic effectors moving from the root cap to the root can move symplastically only through a relatively small area in the centre of the root. Decapped roots are non-responsive to gravity. However, decapped roots whose caps are replaced immediately after decapping are strongly graviresponsive. Thus, gravicurvature occurs only when the root cap contacts the root, and symplastic continuity between the cap and root is not required for gravicurvature. Completely removing mucilage from the root tip renders the root non-responsive to gravity. Taken together, these data suggest that gravitropic effectors move apoplastically through mucilage from the cap to the root.

  4. ECVAM retrospective validation of in vitro micronucleus test (MNT).

    Science.gov (United States)

    Corvi, Raffaella; Albertini, Silvio; Hartung, Thomas; Hoffmann, Sebastian; Maurici, Daniela; Pfuhler, Stefan; van Benthem, Jan; Vanparys, Philippe

    2008-07-01

    In the past decade several studies comparing the in vitro chromosome aberration test (CAT) and the in vitro micronucleus test (MNT) were performed. A high correlation was observed in each of the studies (>85%); however, no formal validation for the micronucleus in vitro assay had been carried out. Therefore, a working group was established by the European Centre for the Validation of Alternative Methods (ECVAM) to perform a retrospective validation of the existing data, in order to evaluate the validity of the in vitro MNT on the basis of the modular validation approach. The primary focus of this retrospective validation was on the evaluation of the potential of the in vitro MNT as alternative to the standard in vitro CAT. The working group evaluated, in a first step, the available published data and came to the conclusion that two studies [German ring trial, von der Hude, W., Kalweit, S., Engelhardt, G. et al. (2000) In-vitro micronucleus assay with Chinese hamster V79 cells: results of a collaborative study with 26 chemicals. Mutat. Res., 468, 137-163, and SFTG International Collaborative Study, Lorge, E., Thybaud, V., Aardema, M., Oliver, J., Wataka, A., Lorenzon, G. and Marzin, D. (2006) SFTG International Collaborative Study on in-vitro micronucleus test I. General conditions and overall conclusions of the study. Mutat. Res., 607, 13-36] met the criteria for a retrospective validation according to the criteria previously defined by the working group. These two studies were evaluated in depth (including the reanalysis of raw data) and provided the information required for assessing the reliability (reproducibility) of the test. For the assessment of the concordance between the in vitro MNT and the in vitro CAT, additional published data were considered. Based on this retrospective validation, the ECVAM Validation Management Team concluded that the in vitro MNT is reliable and relevant and can therefore be used as an alternative method to the in vitro CAT

  5. 饮用水中过量铁和锰对蚕豆根尖细胞微核率的影响%Mutagenicity of Fe and Mn in drinking water on Vicia faba root tip cells detected by micronucleus test

    Institute of Scientific and Technical Information of China (English)

    张加玲; 张瑞莲; 尚晓虹; 董丽芳; 侯文静

    2003-01-01

    目的探讨饮用水中过量的铁和锰的致突变作用.方法采用蚕豆根尖细胞微核技术.结果当水中铁含量超过饮用水卫生标准3~10倍时,蚕豆根尖细胞微核率升高,且微核率与铁剂量间存在着明显的剂量-反应关系.锰对蚕豆根尖细胞微核率升高的作用不明显,只有在剂量高达卫生标准1 000倍时,才会使蚕豆根尖细胞微核率有所增加.结论过量的铁有致突变作用.

  6. Repeated-dose liver micronucleus assay: an investigation with 2-nitropropane, a hepatocarcinogen.

    Science.gov (United States)

    Kawakami, Satoru; Araki, Tetsuro; Nakajima, Mikio; Kusuoka, Osamu; Uchida, Keisuke; Sato, Norihiro; Tanabe, Yoko; Takahashi, Kaori; Wako, Yumi; Kawasako, Kazufumi; Tsurui, Kazuyuki

    2015-03-01

    The utility of the repeated-dose liver micronucleus (RDLMN) assay in the detection of a genotoxic hepatocarcinogen was evaluated. In this paper, a rat hepatocarcinogen, 2-nitropropane (2-NP), was administered orally to young adult rats for 14 and 28 days without a partial hepatectomy or a mitogen, and the micronucleus induction in liver was examined using a simple method to isolate hepatocytes. In addition, a bone marrow micronucleus assay was conducted concomitantly. The frequency of micronucleated hepatocytes induced by 2-NP increased significantly in both the 14- and 28-day repeated-dose studies, while the bone marrow micronucleus assays were negative in each study. These results indicate that the RDLMN assay is useful for detecting a genotoxic hepatocarcinogen that is negative in bone marrow micronucleus assays and is a suitable in vivo genotoxicity test method for integration into a repeated-dose general toxicity study.

  7. Healthy Vision Tips

    Science.gov (United States)

    ... NEI for Kids > Healthy Vision Tips All About Vision About the Eye Ask a Scientist Video Series ... Links to More Information Optical Illusions Printables Healthy Vision Tips Healthy vision starts with you! Use these ...

  8. Diabetes: Dental Tips

    Science.gov (United States)

    ... Diabetes and Oral Health > Diabetes: Dental Tips Diabetes: Dental Tips Main Content Diabetes can cause serious problems ... FOIA Web Policies Privacy Policy National Institute of Dental and Craniofacial Research National Institutes of Health Bethesda, ...

  9. [Effects nutrients on the seedlings root hair development and root growth of Poncirus trifoliata under hydroponics condition].

    Science.gov (United States)

    Cao, Xiu; Xia, Ren-Xue; Zhang, De-Jian; Shu, Bo

    2013-06-01

    Ahydroponics experiment was conducted to study the effects of nutrients (N, P, K, Ca, Mg, Fe, and Mn) deficiency on the length of primary root, the number of lateral roots, and the root hair density, length, and diameter on the primary root and lateral roots of Poncirus trifoliata seedlings. Under the deficiency of each test nutrient, root hair could generate, but was mainly concentrated on the root base and fewer on the root tip. The root hair density on lateral roots was significantly larger than that on primary root, but the root hair length was in adverse. The deficiency of each test nutrient had greater effects on the growth and development of root hairs, with the root hair density on primary root varied from 55.0 to 174.3 mm(-2). As compared with the control, Ca deficiency induced the significant increase of root hair density and length on primary root, P deficiency promoted the root hair density and length on the base and middle part of primary root and on the lateral roots significantly, Fe deficiency increased the root hair density but decreased the root hair length on the tip of primary root significantly, K deficiency significantly decreased the root hair density, length, and diameter on primary root and lateral roots, whereas Mg deficiency increased the root hair length of primary root significantly. In all treatments of nutrient deficiency, the primary root had the similar growth rate, but, with the exceptions of N and Mg deficiency, the lateral roots exhibited shedding and regeneration.

  10. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, lik...

  11. Arabidopsis plasma membrane H+-ATPase genes AHA2 and AHA7 have distinct and overlapping roles in the modulation of root tip H+ efflux in response to low-phosphorus stress.

    Science.gov (United States)

    Yuan, Wei; Zhang, Dongping; Song, Tao; Xu, Feiyun; Lin, Sheng; Xu, Weifeng; Li, Qianfeng; Zhu, Yiyong; Liang, Jiansheng; Zhang, Jianhua

    2017-03-01

    Phosphorus deficiency in soil is one of the major limiting factors for plant growth. Plasma membrane H+-ATPase (PM H+-ATPase) plays an important role in the plant response to low-phosphorus stress (LP). However, few details are known regarding the action of PM H+-ATPase in mediating root proton (H+) flux and root growth under LP. In this study, we investigated the involvement and function of different Arabidopsis PM H+-ATPase genes in root H+ flux in response to LP. First, we examined the expressions of all Arabidopsis PM H+-ATPase gene family members (AHA1-AHA11) under LP. Expression of AHA2 and AHA7 in roots was enhanced under this condition. When the two genes were deficient in their respective Arabidopsis mutant plants, root growth and responses of the mutants to LP were highly inhibited compared with the wild-type plant. AHA2-deficient plants exhibited reduced primary root elongation and lower H+ efflux in the root elongation zone. AHA7-deficient plants exhibited reduced root hair density and lower H+ efflux in the root hair zone. The modulation of H+ efflux by AHA2 or AHA7 was affected by the action of 14-3-3 proteins and/or auxin regulatory pathways in the context of root growth and response to LP. Our results suggest that under LP conditions, AHA2 acts mainly to modulate primary root elongation by mediating H+ efflux in the root elongation zone, whereas AHA7 plays an important role in root hair formation by mediating H+ efflux in the root hair zone. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  12. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  13. Absence of antimutagenicity of Cochlospermum regium (Mart. and Schr. Pilger 1924 by micronucleus test in mice

    Directory of Open Access Journals (Sweden)

    LS. Andrade

    Full Text Available Cochlospermum regium (Mart. and Schr. Pilger, popularly known as "algodãozinho do campo", is a medicinal plant that grows in the Cerrado of Brazil. This plant has been used in traditional medicine against various diseases such as leucorrhoea, gastritis and ulcers. It has also been effective in treating skin problems like pimples, boils and blotches. In the present study, the in vivo antimutagenicity of aqueous extract of C. regium was evaluated. The Micronucleus Test was performed in polychromatic erythrocytes from Swiss male mice treated with one of the four doses of extract of the plant (19, 38, 76 and 114 mg.kg-1 body weight, administered by intraperitonial injection (i.p. simultaneously with cyclophosphamide (24 mg.kg-1 b.w. or mitomycin C (4 mg.kg-1 b.w.. The cytotoxicity was evaluated by polychromatic and normochromatic erythrocytes ratio (PCE/NCE. The results showed no significant reduction of the micronucleated polychromatic erythrocytes frequency (P > 0.05. In conclusion, the data indicate that C. regium roots aqueous extract, for the conditions used, did not exhibit the antimutagenic effect.

  14. 微核技术在蚕豆氯化钠胁迫和碳酸钠胁迫中的应用研究%Application of Micronucleus Test Technology to Vicia faba L.Under the Stress of NaCl or Na2CO3

    Institute of Scientific and Technical Information of China (English)

    闫秋洁; 罗明华; 唐倩; 陈嫚

    2012-01-01

    The aim was is explore the application approach of applying the micronuclear testing technology to NaCl stress and Na2CO3 stress in Vicia faba L.. The seeds were soaked under the concentration of 0.5%-4.0% NaCl and 0.5%-3.0% Na2CO3 respectively, for contrast with distilled water treatment. And then, the germination rate, the micronucleus frequency, the relative salinity-injury rate and salt-sensitivity index of the seeds were calculated. And the variance analysis and multiple comparisons were used to study relation in treatments. The results showed that: (1) the germination rate and the relative salinity-injury rate of Vicia faba were reduced with the increasing concentration of NaCl and Na2CO3, while the micronucleus rate of Vicia faba root-tip cell increased firstly and then decreased, the peak value appeared in 2% NaCl and 2% Na2CO3 respectively. (2)There were significant differences {P<0.05) and very significant differences (P<0.01) in germination and micronucleus rate among different treatments of NaCl concentration and Na2CO3 concentration. (3) Under the same concentration value of NaCl and Na2CO3, the treatment of Na2CO3 stress showed higher influence in the germination rate, the relative salinity- injury rate, the micronucleus rate and the relative salinity-injury rate compare to the treatment of NaCl stress. Therefore, the suitable concentrate range of applying the micronuclear testing technology to NaCl stress or Na2CO3 stress in Vicia faba L. Both was 0.5%-2%.%为探索微核技术在蚕豆耐盐胁迫中的应用途径.以蒸馏水处理为对照,测定在浓度为0.5%~4.0%的NaCl和0.5%~3.0%的Na2CO3溶液处理下蚕豆种子的发芽率和微核率,计算相对盐害率和盐敏指数,通过方差分析和多重比较对比其变化趋势.结果表明:(1)蚕豆种子的发芽率和相对盐害率随盐胁迫浓度的升高而降低,而微核率和盐敏指数随盐胁迫浓度的升高先增大后减小,峰值时的浓度为2%;(2)发

  15. Micronucleus frequency in exfoliated buccal cells from hairdresser who expose to hair products

    Directory of Open Access Journals (Sweden)

    Koh Hui Yee

    2015-06-01

    Full Text Available Background: Hairdresser is one of the fastest growing occupations in today’s society. Hairdresser help styling, cutting, colouring, perming, curling, straightening hair and various treatment to customer. Somehow, hairdresser are constantly exposed to chemical substances such as aromatic amines, hydrogen peroxide, thioglycolic acid, formaldehyde in hair products which can cause damage to human’s genome. Micronucleus is one of the effective biomarker for processes associated with the induction of DNA damage. Purpose: The aim of this study was to determine the micronucleus frequencies in buccal mucosa epithelial cells of hairdresser who were exposed to chemical of hair products. Method: This study was conducted on twenty female subjects, who were divided into 2 groups: exposed and non-exposed (control group. All subjects recruited were working in the same beauty salon. Buccal cells were obtained from each individual by using cytobrush. The cells were stained with modified Feulgen-Ronssenback method and counting of micronucleus per 1000 cell was done under light microscope. The data were analyzed using independent t-test and one-way Anova (p<0.05. Result: The result showed a significant difference in micronucleus frequency between 2 groups. There were a significantly increase of micronucleus frequency in hairdressers and increase of  micronucleus frequency with the longer duration of exposure. Conclusion: It concluded that the chemical substances of hair products had affected the micronucleus frequency ofthe epithelial cells in buccal mucosa of hairdressers.

  16. Successful micronucleus testing with the EPI/001 3D reconstructed epidermis model: preliminary findings.

    Science.gov (United States)

    Andres, E; Molinari, J; Remoué, N; Sá-Rocha, V M; Barrichello, C; Hurtado, S P

    2012-03-18

    Currently, the cosmetics industry relies on the results of in vitro genotoxicity tests to assess the safety of chemicals. Although the cytokinesis-block micronucleus (CBMN) test for the detection of cells that have divided once is routinely used and currently accepted by regulatory agencies, it has some limitations. Reconstituted human epidermis (RHE) is widely used in safety assessments because its physiological properties resemble those of the skin, and because it allows testing of substances such as hydrophobic compounds. Thus, the micronucleus test is being adapted for application in RHE-reconstructed tissues. Here we investigated whether two different reconstructed epidermis models (EPI/001 from Straticell, and RHE/S/17 from Skinethic) are suitable for application of the micronucleus test. We found that acetone does not modify micronucleus frequency, cell viability, and model structure, compared with non-treated RHE. Treatment of the EPI/001 model with mitomycin C and vinblastine resulted in a dose-dependent increase of micronucleus frequency as well as a decrease of tissue viability and of binucleated cell rate, while no changes of the epidermal structure were observed. The number of binucleated cells obtained with the RHE/S/17 model was too small to permit micronucleus testing. These results indicate that the proliferative rate of the tissue used is a critical parameter in performing the micronucleus test on a 3D model.

  17. clinical analysis of 60 cases with Root tip and root osteotomies correction between babbling at ashdod slot before deformity%牙根尖下及根间截骨矫正前牙牙槽突前突畸形60例临床分析

    Institute of Scientific and Technical Information of China (English)

    孙雪玉; 陈菲

    2012-01-01

    目的 对牙根尖下及根间截骨矫正前牙牙槽突前突畸形60例进行临床分析.方法 本组共60例求诊者.男性22例,女性38例;年龄20~49岁.其中,上、下颌牙槽突前突者37例,单纯上颌牙槽突前突者18例,单纯下颌牙槽突前突者5例.所有患者均未接受过正畸治疗.结果 本组共60例患者,共移动前牙380颗,拔牙108颗,截为96个牙骨段,平均每牙槽截骨1.6段,术后随访1~14年.术后无感染、严重出血、牙髓坏死及牙变色等.结论 本手术操作简单,并发症少,美容效果迅速,疗效满意,值得在美容口腔科中推广应用.%OBJECTIVE To analyze 60 cases with root tip and root osteotomies correction between babbling at ashdod slot before deformity. METHODS 60 cases were included with 22 males and 38 females (age: 20-49 years old). Among them, 37 cases showed upper teeth before the alveolar ashdod, and 18 cases showed pure maxillary teeth at the trough before dash forward, 5 cases showed pure mandible alveolar axon. All of the patients did not receive the orthodontic treatment. RESULTS A-mong 60 patients, 380 front teeth of tooth were moved, 108 teeth were extracted, and they were cut into 96 teeth with bone segments. The average alveolar bone section was 1.6 section. The follow-up was 1-14 years. There were no postoperative infection, serious bleeding, pulp necrosis and teeth discoloration. CONCLUSION The operation was simple, less complications, hairdressing effect quickly, and the results were satisfactory, which is worth in the beauty of the dental application.

  18. [Bacterial reverse mutation test and micronucleus test of fucoxanthin oil from microalgae].

    Science.gov (United States)

    Iio, Kumiko; Okada, Yumika; Ishikura, Masaharu

    2011-01-01

    Fucoxanthin-containing oil extracted from microalga, Chaetoseros sp., was subjected to genotoxicity studies, the bacterial reverse mutation test and the micronucleus test in mice. The number of revertant colonies in fucoxanthin oil-treated plates of all strains tested was less than twice the number of colonies in the negative control, regardless of the presence of the metabolic activator in the bacterial reverse mutation test. In the micronucleus test, 500, 1,000, 2,000 mg/kg body weight of fucoxanthin oil was administered orally to mice. There was no significant increase in micronucleus frequency in bone marrow cells. These results suggest that fucoxanthin oil does not exhibit genotoxicity.

  19. Assessment of methyl methacrylate genotoxicity by the micronucleus test.

    Science.gov (United States)

    Araújo, Amarildo Mariano de; Alves, Guilherme Rodrigues; Avanço, Guilherme Trevisan; Parizi, José Luiz Santos; Nai, Gisele Alborghetti

    2013-01-01

    The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.

  20. Tips for Interpretation

    Institute of Scientific and Technical Information of China (English)

    陈鹏; 罗新平

    2015-01-01

    this article offers tips for interpreting, including interpretation techniques and improving interpreting skills by the practice of listening, speaking, reading and writing to better interpreting performance.

  1. Tradescantia micronucleus test indicates genotoxic potential of traffic emissions in European cities

    DEFF Research Database (Denmark)

    Klumpp, A.; Ansel, W.; Klumpp, G.

    2006-01-01

    , the Tradescantia micronucleus (Trad-MCN) test was applied to examine the genotoxicity of urban air pollution. Cuttings of Tradescantia clone #4430 were exposed to ambient air at 65 monitoring sites in 10 conurbations employing a standardised methodology. The tests revealed an elevated genotoxic potential mainly...... is recommended in order to reduce the variability of results due to varying environmental conditions. The Tradescantia micronucleus test can be used to assess genotoxic potential at urban sites....

  2. Root cap influences root colonisation by Pseudomonas fluorescens SBW25 on maize.

    Science.gov (United States)

    Humphris, Sonia N; Bengough, A Glyn; Griffiths, Bryan S; Kilham, Ken; Rodger, Sheena; Stubbs, Vicky; Valentine, Tracy A; Young, Iain M

    2005-09-01

    We investigated the influence of root border cells on the colonisation of seedling Zea mays roots by Pseudomonas fluorescens SBW25 in sandy loam soil packed at two dry bulk densities. Numbers of colony forming units (CFU) were counted on sequential sections of root for intact and decapped inoculated roots grown in loose (1.0 mg m(-3)) and compacted (1.3 mg m(-3)) soil. After two days of root growth, the numbers of P. fluorescens (CFU cm(-1)) were highest on the section of root just below the seed with progressively fewer bacteria near the tip, irrespective of density. The decapped roots had significantly more colonies of P. fluorescens at the tip compared with the intact roots: approximately 100-fold more in the loose and 30-fold more in the compact soil. In addition, confocal images of the root tips grown in agar showed that P. fluorescens could only be detected on the tips of the decapped roots. These results indicated that border cells, and their associated mucilage, prevented complete colonization of the root tip by the biocontrol agent P. fluorescens, possibly by acting as a disposable surface or sheath around the cap.

  3. ADHD: Tips to Try

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness ADHD: Tips to Try KidsHealth > For Teens > ADHD: Tips to Try Print A A A en español TDAH: Consejos que puedes probar ADHD , or attention deficit hyperactivity disorder, is a medical ...

  4. Gravity sensing in tip-growing cells.

    Science.gov (United States)

    Sievers, A; Buchen, B; Hodick, D

    1996-08-01

    In addition to the statocytes of roots and shoots, a number of tip-growing cells also sense gravity, which influences the cells' growth and development. Since these tip-growing cells are highly suitable for observations in vivo, the movement and sedimentation of their statoliths can be studied in detail. Experimental manipulation by centrifugation, drug application, optical tweezers or microgravity can be monitored by light microscopy. The statoliths are localized in distinct cytoplasmic areas by interactions with actin filaments or microtubules, and their sedimentation seems to be narrowly confined. Since gravisensing and the graviresponse take place within the same cell, the gravitropic signal transduction chain is not complicated by signal transmission between sensing and responding cells. Studies on tip-growing cells have now enabled the formulation of models explaining positive and negative gravitropism.

  5. Closed soilless growing system for producing strawberry bare root transplants and runner tips Sistema fechado de cultivo sem solo para produção de mudas de raízes nuas e de pontas de estolões de morangueiro

    Directory of Open Access Journals (Sweden)

    Gustavo Giménez

    2008-12-01

    Full Text Available The objective of this work was to test a closed soilless growing system for producing bare root transplants and runner tips of two strawberry clones, using two categories of substrates. The system used corrugated roofing panels of fiber-cement, over which a substrate layer was used as a growing bed. The nutrient solution was pumped from a reservoir toward the upper end of the roofing panels and drained back to a reservoir. Plant growth and development were determined for two advanced strawberry clones, grown in sand or in Plantmax organic substrate. Growth of the stock plants and the number and dry mass of bare root transplants were similar in the substrates, but bare roots differed in their crown diameters by substrate. For number of runner tips, no significant differences were found in total, small, and medium categories in the substrates. A mean production of about 590 runner tips per square meter and 145 bare root transplants per square meter was obtained. For both clones, a large number of bare root transplants and runner tips of adequate size were produced in the closed soilless growing system using sand or organic substrate.O objetivo deste trabalho foi testar um sistema fechado de cultivo sem solo, para a produção de mudas e pontas de estolões de dois clones de morangueiro, com uso de duas categorias de substrato. O sistema foi constituído por um leito de cultivo formado por telhas de fibrocimento, com uma camada de substrato como leito de cultivo. A solução nutritiva foi bombeada de um reservatório até a extremidade mais alta da telha e drenada de volta ao reservatório. Foram determinados o crescimento e o desenvolvimento de dois clones avançados de morangueiro, plantados na areia e no substrato orgânico Plantmax. O crescimento das plantas matrizes foi similar nos dois substratos. O número e a massa de matéria seca das mudas de raízes nuas foram semelhantes nos dois substratos, mas diferiram nos diâmetros de coroa. Quanto

  6. Statistical analysis of the hen's egg test for micronucleus induction (HET-MN assay).

    Science.gov (United States)

    Hothorn, Ludwig A; Reisinger, Kerstin; Wolf, Thorsten; Poth, Albrecht; Fieblinger, Dagmar; Liebsch, Manfred; Pirow, Ralph

    2013-09-18

    The HET-MN assay (hen's egg test for micronucleus induction) is different from other in vitro genotoxicity assays in that it includes toxicologically important features such as absorption, distribution, metabolic activation, and excretion of the test compound. As a promising follow-up to complement existing in vitro test batteries for genotoxicity, the HET-MN is currently undergoing a formal validation. To optimize the validation, the present study describes a critical analysis of previously obtained HET-MN data to check the experimental design and to identify the most appropriate statistical procedure to evaluate treatment effects. Six statistical challenges (I-VI) of general relevance were identified, and remedies were provided which can be transferred to similarly designed test methods: a Williams-type trend test is proposed for overdispersed counts (II) by means of a square-root transformation which is robust for small sample sizes (I), variance heterogeneity (III), and possible downturn effects at high doses (IV). Due to near-to-zero or even zero-count data occurring in the negative control (V), a conditional comparison of the treatment groups against the mean of the historical controls (VI) instead of the concurrent control was proposed, which is in accordance with US-FDA recommendations. For the modified Williams-type tests, the power can be estimated depending on the magnitude and shape of the trend, the number of dose groups, and the magnitude of the MN counts in the negative control. The experimental design used previously (i.e. six eggs per dose group, scoring of 1000 cells per egg) was confirmed. The proposed approaches are easily available in the statistical computing environment R, and the corresponding R-codes are provided.

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... vs. risks? What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A ... likely to require a TIPS. top of page What are some common uses of the procedure? A ...

  9. Tonoplast Aquaporins Facilitate Lateral Root Emergence.

    Science.gov (United States)

    Reinhardt, Hagen; Hachez, Charles; Bienert, Manuela Désirée; Beebo, Azeez; Swarup, Kamal; Voß, Ute; Bouhidel, Karim; Frigerio, Lorenzo; Schjoerring, Jan K; Bennett, Malcolm J; Chaumont, Francois

    2016-03-01

    Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip mutants showed no or minor reduction in growth of the main root. This phenotype was due to the retardation of LRP emergence. Live cell imaging revealed that tight spatiotemporal control of TIP abundance in the tonoplast of the different LRP cells is pivotal to mediating this developmental process. While lateral root emergence is correlated to a reduction of AtTIP1;1 and AtTIP1;2 protein levels in LRPs, expression of AtTIP2;1 is specifically needed in a restricted cell population at the base, then later at the flanks, of developing LRPs. Interestingly, the LRP emergence phenotype of the triple tip mutants could be fully rescued by expressing AtTIP2;1 under its native promoter. We conclude that TIP isoforms allow the spatial and temporal fine-tuning of cellular water transport, which is critically required during the highly regulated process of LRP morphogenesis and emergence.

  10. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... wings. The literature on four different designs is reviewed: the end-plate propeller; the two-sided, shifted end-plate propeller; the tip-fin propeller; and the bladelet propeller. The conclusion is that it is indeed possible to design tip-modified propellers that, relative to an optimum conventional...

  11. The actin Cytoskeleton in Root Hairs: a cell elongation device

    NARCIS (Netherlands)

    Ketelaar, T.; Emons, A.M.C.

    2009-01-01

    The actin cytoskeleton plays an important role in root hair development. It is involved in both the delivery of growth materials to the expanding tip of root hairs and the regulation of the area of tip growth. This review starts with a discussion of the techniques that are available to visualize the

  12. The actin Cytoskeleton in Root Hairs: a cell elongation device

    NARCIS (Netherlands)

    Ketelaar, T.; Emons, A.M.C.

    2009-01-01

    The actin cytoskeleton plays an important role in root hair development. It is involved in both the delivery of growth materials to the expanding tip of root hairs and the regulation of the area of tip growth. This review starts with a discussion of the techniques that are available to visualize the

  13. Eye Drop Tips

    Science.gov (United States)

    ... Involved News About Us Donate In This Section Eye Drop Tips en Español email Send this article ... the reach of children. Steps For Putting In Eye Drops: Start by tilting your head backward while ...

  14. Bed Bug Tips

    Science.gov (United States)

    How to deal with bed bugs in one printable page. Ten tips include ensuring correct insect identification, reducing clutter, understand integrated pest management, using mattress and box spring encasements, and heat treatment.

  15. Impact of cell cycle delay on micronucleus frequency in TK6 cells.

    Science.gov (United States)

    Sobol, Zhanna; Spellman, Richard A; Thiffeault, Catherine; Dobo, Krista L; Schuler, Maik

    2014-01-01

    Previous studies with TK6 cells have shown that extending the recovery period after pulse treatment allows for greater micronucleus expression for some compounds. This study explores the role of cell cycle delay in micronucleus expression after pulse treatment with three model genotoxins [mitomycin C, etoposide (ETOP), vinblastine]. Cells were treated for 4 hr and allowed to recover for 36 hr with samples removed at various time points during the recovery period and analyzed for cell cycle distribution, apoptosis and micronucleus frequency. Our results show that mitomycin C causes cell cycle delay for 20 hr after pulse treatment and cell cycle perturbation is no longer evident after 36 hr of recovery. The micronucleus frequency of cells sampled at 36 hr is doubled when compared with cells sampled at 20 hr after mitomycin C removal. When cells were treated with indirect acting genotoxins (ETOP, vinblastine), cell cycle perturbation was not observed at the 20 hr time point. Micronucleus frequency after treatment with either ETOP or vinblastine did not differ between the 20 hr and the 36 hr time point. All three compounds induced similar levels of apoptosis ranging from 4.5 to 5.6% with maximum induction occurring at the 36-hr time point. We conclude that TK6 cells exhibit extended cell cycle arrest after exposure to MMC and can go on to express micronuclei, after overcoming cell cycle arrest.

  16. Mutagenicity testing with transgenic mice. Part I: Comparison with the mouse bone marrow micronucleus test

    Directory of Open Access Journals (Sweden)

    Wahnschaffe U

    2005-01-01

    Full Text Available Abstract As part of a larger literature study on transgenic animals in mutagenicity testing, test results from the transgenic mutagenicity assays (lacI model; commercially available as the Big Blue® mouse, and the lacZ model; commercially available as the Muta™Mouse, were compared with the results on the same substances in the more traditional mouse bone marrow micronucleus test. 39 substances were found which had been tested in the micronucleus assay and in the above transgenic mouse systems. Although, the transgenic animal mutation assay is not directly comparable with the micronucleus test, because different genetic endpoints are examined: chromosome aberration versus gene mutation, the results for the majority of substances were in agreement. Both test systems, the transgenic mouse assay and the mouse bone marrow micronucleus test, have advantages and they complement each other. However, the transgenic animal assay has some distinct advantages over the micronucleus test: it is not restricted to one target organ and detects systemic as well as local mutagenic effects.

  17. Relationship between radiation induced dicentric chromosome aberrations and micronucleus formation in human lymphocytes.

    Science.gov (United States)

    Hatayoglu, S E; Orta, T

    2007-06-01

    Chromosome damage measured by the chromosome aberration technique is a reliable method to assess the radiation dose absorbed by cells. However, this technique has some disadvantages. Scoring is difficult and requires skill and experience which of these lead low number of cell counts. The micronucleus (MN) technique which also measures chromosome losses has easy scoring criteria leading high numbers of cell counts and therefore holds more statistical power. In this study, the relationship between the results of the micronucleus technique and those obtained by the chromosome aberration technique was investigated after radiation doses of 1Gy, 2Gy, 3Gy and 4Gy to peripheral blood lymphocytes of 3 healthy individuals. Increases in the chromosome damage after radiation were observed in both techniques. When the dicentric aberration frequencies that were measured in the chromosome aberration technique and the micronucleus frequencies were compared, no difference (p > 0.05) between these two independent measures of radiation damage was reported. The relationship between the micronuclei and the free acentric chromosome aberrations measured in the chromosome aberration technique was not significant as well as that between the dicentrics and micronuclei. On the basis of the relationship between the dicentric aberrations and the micronucleus frequencies, the micronucleus technique with an easy and short-term application and with an easy scoring can be used as an alternative to the chromosome aberration technique.

  18. DEK over-expression promotes mitotic defects and micronucleus formation.

    Science.gov (United States)

    Matrka, Marie C; Hennigan, Robert F; Kappes, Ferdinand; DeLay, Monica L; Lambert, Paul F; Aronow, Bruce J; Wells, Susanne I

    2015-01-01

    The DEK gene encodes a nuclear protein that binds chromatin and is involved in various fundamental nuclear processes including transcription, RNA splicing, DNA replication and DNA repair. Several cancer types characteristically over-express DEK at the earliest stages of transformation. In order to explore relevant mechanisms whereby DEK supports oncogenicity, we utilized cancer databases to identify gene transcripts whose expression patterns are tightly correlated with that of DEK. We identified an enrichment of genes involved in mitosis and thus investigated the regulation and possible function of DEK in cell division. Immunofluorescence analyses revealed that DEK dissociates from DNA in early prophase and re-associates with DNA during telophase in human keratinocytes. Mitotic cell populations displayed a sharp reduction in DEK protein levels compared to the corresponding interphase population, suggesting DEK may be degraded or otherwise removed from the cell prior to mitosis. Interestingly, DEK overexpression stimulated its own aberrant association with chromatin throughout mitosis. Furthermore, DEK co-localized with anaphase bridges, chromosome fragments, and micronuclei, suggesting a specific association with mitotically defective chromosomes. We found that DEK over-expression in both non-transformed and transformed cells is sufficient to stimulate micronucleus formation. These data support a model wherein normal chromosomal clearance of DEK is required for maintenance of high fidelity cell division and chromosomal integrity. Therefore, the overexpression of DEK and its incomplete removal from mitotic chromosomes promotes genomic instability through the generation of genetically abnormal daughter cells. Consequently, DEK over-expression may be involved in the initial steps of developing oncogenic mutations in cells leading to cancer initiation.

  19. Tissue specific localization of root infection by fungal pathogens: role of root border cells.

    Science.gov (United States)

    Gunawardena, Uvini; Hawes, Martha C

    2002-11-01

    When roots of pea seedlings were inoculated uniformly with spores of Nectria haematocca or other pea pathogenic fungi, more than 90% developed lesions in the region of elongation within 3 days. More mature regions of most roots as well as the tip showed no visible signs of infection. Yet, microscopic observation revealed that 'mantles,' comprised of fungal hyphae intermeshed with populations of border cells, covered the tips of most roots. After physical detachment of the mantle, the underlying tip of most roots was found to be free of infection. Mantle-covered root tips did not respond to invasion of their border cells by activation of known defense genes unless there was invasion of the tip itself, as revealed by the presence of a lesion. Concomitant with the activation of defense genes was the induction of a cell-wall degrading enzyme whose expression is a marker for renewed production of border cells. Mantle formation did not occur in response to nonpathogens. The data are consistent with the hypothesis that border cells serve as a host-specific 'decoy' that protects root meristems by inhibiting fungal infection of the root tip.

  20. Screening potential genotoxic effect of aquatic plant extracts using the mussel micronucleus test

    Directory of Open Access Journals (Sweden)

    Bettina Eck-Varanka

    2016-01-01

    Full Text Available Objective: To assess the genotoxic potential of selected aquatic macrophytes: Ceratophyllum demersum L. (hornwort, family Ceratophyllaceae, Typha angustifolia L. (narrowleaf cattail, family Typhaceae, Stratiotes aloides L. (water soldier, family Butomaceae, and Oenanthe aquatica (L. Poir. (water dropwort, family Umbelliferae. Methods: For genotoxicity assessment, the mussel micronucleus test was applied. Micronucleus frequency was determined from the haemolymph of Unio pictorum L. (painter’s mussel. In parallel, total and hydrolisable tannin contents were determined. Results: All plant extracts elucidated significant mutagenic effect. Significant correlation was determined between tannin content and mutagenic capacity. Conclusions: The significant correlation between genotoxicity as expressed by micronucleus frequency and tannin content (both total and hydrolisable tannins indicate that tannin is amongst the main compounds being responsible for the genotoxic potential. It might be suggested that genotoxic capacity of these plants elucidate a real ecological effect in the ecosystem.

  1. [Micronucleus test of human oral buccal epithelium: problems, progress and prospects].

    Science.gov (United States)

    Kalaev, V N; Artiukhov, V G; Nechaeva, M S

    2014-01-01

    The articles by russian and foreign authors for the period from 2000 to 2012, devoted to the problems of application, analysis and interpretation of the results of micronucleus test in human buccal epithelium has been analyzed in the review. Nuclear abnormality founding in the cells of the oral mucosa has been described. The paper summarizes works devoted to the analysis of the influence of the micronucleus test methods (painting, taking scrapings) to its results. Modern opinions about the factors of different etiology (sex, age, genotype, psycho-physiological characteristics, immune status, diseases of different etiology, man-made pollution, climatic and geographical conditions, ionizing and nonionizing radiation, chemical compounds (drugs, dietary supplements, androgenic steroids, etc.), dental fillings, occupational exposures, alcohol, using tobacco blends) inducing the estimation of nuclear aberration has been summarized as a scheme. The problems and unresolved issues related to the peculiarities of micronucleus test has been noted.

  2. Screening potential genotoxic effect of aquatic plant extracts using the mussel micronucleus test

    Institute of Scientific and Technical Information of China (English)

    Bettina Eck-Varanka; Nora Kovts; Katalin Hubai; Gbor Paulovits; rpd Ferincz; Eszter Horvth

    2016-01-01

    Objective:To assess the genotoxic potential of selected aquatic macrophytes:Ceratophyllum demersum L. (hornwort, family Ceratophyllaceae),Typha angustifolia L. (narrowleaf cattail, family Typhaceae),Stratiotes aloides L. (water soldier, family Butomaceae), andOenanthe aquatica (L.) Poir. (water dropwort, family Umbelliferae). Methods: For genotoxicity assessment, the mussel micronucleus test was applied. Micronucleus frequency was determined from the haemolymph ofUnio pictorum L. (painter’s mussel). In parallel, total and hydrolisable tannin contents were determined. Results:All plant extracts elucidated significant mutagenic effect. Significant correlation was determined between tannin content and mutagenic capacity. Conclusions:The significant correlation between genotoxicity as expressed by micronucleus frequency and tannin content (both total and hydrolisable tannins) indicate that tannin is amongst the main compounds being responsible for the genotoxic potential. It might be suggested that genotoxic capacity of these plants elucidate a real ecological effect in the ecosystem.

  3. Intraoperative fracture of phacoemulsification tip

    Directory of Open Access Journals (Sweden)

    Dewang Angmo

    2014-01-01

    Full Text Available Phacoemulsification (phaco is an established procedure for cataract extraction and has undergone a significant advances in techniques, machines and phaco tips. The Aspiration Bypass System (ABS phaco tip was introduced for phacoemulsification in 1998. The ABS tip allows fluid to be drawn through the opening when the phaco tip is occluded by nuclear material. The ABS tip allowed the safe use of high vacuum and flow rates and improved chamber stability by decreasing surge and therefore reducing intraoperative complications. To date, no disadvantages of ABS tips have been reported. We report a unique case of an intraoperative break of an ABS phaco tip during routine cataract surgery.

  4. Intraoperative fracture of phacoemulsification tip.

    Science.gov (United States)

    Angmo, Dewang; Khokhar, Sudarshan K; Ganguly, Anasua

    2014-01-01

    Phacoemulsification (phaco) is an established procedure for cataract extraction and has undergone a significant advances in techniques, machines and phaco tips. The Aspiration Bypass System (ABS) phaco tip was introduced for phacoemulsification in 1998. The ABS tip allows fluid to be drawn through the opening when the phaco tip is occluded by nuclear material. The ABS tip allowed the safe use of high vacuum and flow rates and improved chamber stability by decreasing surge and therefore reducing intraoperative complications. To date, no disadvantages of ABS tips have been reported. We report a unique case of an intraoperative break of an ABS phaco tip during routine cataract surgery.

  5. Intraoperative Fracture of Phacoemulsification Tip

    Science.gov (United States)

    Angmo, Dewang; Khokhar, Sudarshan K.; Ganguly, Anasua

    2014-01-01

    Phacoemulsification (phaco) is an established procedure for cataract extraction and has undergone a significant advances in techniques, machines and phaco tips. The Aspiration Bypass System (ABS) phaco tip was introduced for phacoemulsification in 1998. The ABS tip allows fluid to be drawn through the opening when the phaco tip is occluded by nuclear material. The ABS tip allowed the safe use of high vacuum and flow rates and improved chamber stability by decreasing surge and therefore reducing intraoperative complications. To date, no disadvantages of ABS tips have been reported. We report a unique case of an intraoperative break of an ABS phaco tip during routine cataract surgery. PMID:24669153

  6. Mutagenicity testing with transgenic mice. Part I: Comparison with the mouse bone marrow micronucleus test

    OpenAIRE

    Wahnschaffe U; Bitsch A; Kielhorn J; Mangelsdorf I

    2005-01-01

    Abstract As part of a larger literature study on transgenic animals in mutagenicity testing, test results from the transgenic mutagenicity assays (lacI model; commercially available as the Big Blue® mouse, and the lacZ model; commercially available as the Muta™Mouse), were compared with the results on the same substances in the more traditional mouse bone marrow micronucleus test. 39 substances were found which had been tested in the micronucleus assay and in the above transgenic mouse system...

  7. Micronucleus frequency in Danish schoolchildren and their mothers from the DEMOCOPHES population

    DEFF Research Database (Denmark)

    Mørck, Thit A.; Vande Loock, Kim; Poulsen, Maria Bech

    2016-01-01

    Micronucleus (MN) frequency is a biomarker for early genetic effects which is often used in humanbiomonitoring studies. Increased frequency of micronuclei has been associated with high levelsof traffic exposure. Further high MN frequency was found predictive for cancer development inseveral studies...... organic pollutants and dioxin-like activity measured in the sameparticipants. The MN frequency analysis was performed with the cytokinesis-block micronucleus(CBMN) assay and included 100 children and 119 mothers. We found a significant correlationbetween mothers and children in the levels of micronuclei...... MNfrequencies and the other biomarkers measured in the same participants....

  8. Collection of gravitropic effectors from mucilage of electrotropically-stimulated roots of Zea mays L

    Science.gov (United States)

    Fondren, W. M.; Moore, R.

    1987-01-01

    We placed agar blocks adjacent to tips of electrotropically stimulated primary roots of Zea mays. Blocks placed adjacent to the anode-side of the roots for 3 h induced significant curvature when subsequently placed asymmetrically on tips of vertically-oriented roots. Curvature was always toward the side of the root unto which the agar block was placed. Agar blocks not contacting roots and blocks placed adjacent to the cathode-side of electrotropically stimulated roots did not induce significant curvature when placed asymmetrically on tips of vertically-oriented roots. Atomic absorption spectrophotometry indicated that blocks adjacent to the anode-side of electrotropically-stimulated roots contained significantly more calcium than (1) blocks not contacting roots, and (2) blocks contacting the cathode-side of roots. These results demonstrate the presence of a gradient of endogenous Ca in mucilage of electrotropically-stimulated roots (i.e. roots undergoing gravitropic-like curvature).

  9. Evaluation of a multi-endpoint assay in rats, combining the bone-marrow micronucleus test, the Comet assay and the flow-cytometric peripheral blood micronucleus test.

    Science.gov (United States)

    Bowen, Damian E; Whitwell, James H; Lillford, Lucinda; Henderson, Debbie; Kidd, Darren; Mc Garry, Sarah; Pearce, Gareth; Beevers, Carol; Kirkland, David J

    2011-05-18

    With the publication of revised draft ICH guidelines (Draft ICH S2), there is scope and potential to establish a combined multi-end point in vivo assay to alleviate the need for multiple in vivo assays, thereby reducing time, cost and use of animals. Presented here are the results of an evaluation trial in which the bone-marrow and peripheral blood (via MicroFlow(®) flow cytometry) micronucleus tests (looking at potential chromosome breakage and whole chromosome loss) in developing erythrocytes or young reticulocytes were combined with the Comet assay (measuring DNA strand-breakage), in stomach, liver and blood lymphocytes. This allowed a variety of potential target tissues (site of contact, site of metabolism and peripheral distribution) to be assessed for DNA damage. This combination approach was performed with minimal changes to the standard and regulatory recommended sampling times for the stand-alone assays. A series of eight in vivo genotoxins (2-acetylaminofluorene, benzo[a]pyrene, carbendazim, cyclophosphamide, dimethylnitrosamine, ethyl methanesulfonate, ethyl nitrosourea and mitomycin C), which are known to act via different modes of action (direct- and indirect-acting clastogens, alkylating agents, gene mutagens, cross-linking and aneugenic compounds) were tested. Male rats were dosed at 0, 24 and 45 h, and bone marrow and peripheral blood (micronucleus endpoint), liver, whole blood and stomach (Comet endpoint) were sampled at three hours after the last dose. Comet and micronucleus responses were as expected based on available data for conventional (acute) stand-alone assays. All compounds were detected as genotoxic in at least one of the endpoints. The importance of evaluating both endpoints was highlighted by the uniquely positive responses for certain chemicals (benzo[a]pyrene and 2-acetylaminofluorene) with the Comet endpoint and certain other chemicals (carbendazim and mitomycin C) with the micronucleus endpoint. The data generated from these

  10. New phacoemulsification tip with a grooved, threaded-tip construction.

    Science.gov (United States)

    Watanabe, Akinari

    2011-07-01

    To visually compare ultrasonic tip vibrations between a phaco tip with internal grooves (threaded tip) and a standard phaco tip during continuous-mode ultrasound (US) using ultra-high-speed digital video imaging. Watanabe Eye Clinic, Hyogo, Japan. Experimental study. The threaded tip was constructed by creating grooves inside a standard phaco tip using a screw. An ultra-high-speed digital video camera was used to record the image during continuous-mode US. Samples used in the test chamber during phacoemulsification included a piece of chestnut as a representative human lens sample and actual human lens fragments. Ultra-high-speed digital images showed that the threaded tip created a larger amount of cavitation than the standard phaco tip during US oscillation. Phacoemulsification of the sample using the standard phaco tip produced a chattering motion, making it difficult to maintain a steady tip position. The threaded tip produced little chattering motion, making it relatively easy to maintain a steady tip position. Once a piece of sample was gripped by the threaded tip, it was shaved and aspirated into the threaded tip without chattering motion. The mean effective phacoemulsification time (EPT) of the threaded tip was significantly shorter than that of the normal phaco tip (6.0 seconds ± 1.9 [SD] versus 15.4 ± 1.3 seconds; P=.002). The threaded tip created larger amounts of cavitation and had strong destructive and holding power. This threaded construction is simple to produce and appears to be very effective for phacoemulsification. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  11. Cyclic programmed cell death stimulates hormone signaling and root development in Arabidopsis

    NARCIS (Netherlands)

    Xuan, Wei; Band, Leah R.; Kumpf, Robert P.; Rybel, De Bert

    2016-01-01

    The plant root cap, surrounding the very tip of the growing root, perceives and transmits environmental signals to the inner root tissues. In Arabidopsis thaliana, auxin released by the root cap contributes to the regular spacing of lateral organs along the primary root axis. Here, we show that

  12. Observations on the feeding and symptomatology of xiphinema and longidorus on selected host roots.

    Science.gov (United States)

    Cohn, E

    1970-04-01

    In vitro feeding of Xiphinema brevicolle, X. index and Longidorus africanus on roots of host seedlings is described. Both Xiphinema spp. fed mainly along roots rather than at tips and up to several days at a single site. Feeding of L. africanus was confined to root tips and lasted up to 15 min. No visible short term reaction of roots parasitized by the Xiphinema spp. could be discerned, but both swelling and cessation of growth of root tips were observed within 20 hr after feeding by L. africanus. Long-term (12-month) symptoms on roots of several host plants caused by cultured populations of X. brevicolle, X. index, X. italiae, L. africanus and L. brevicaudatus are described. All the Xiphinema spp. caused a thinning and distinct darkening of root systems and, at some sites, a breakdown of the cortex. Both species of Longidorus caused stubby and swollen root tips. Root symptom severity was in proportion to nematode population levels.

  13. Taxicab tipping and sunlight

    Science.gov (United States)

    2017-01-01

    Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences. PMID:28594917

  14. Association between micronucleus frequency and cervical intraepithelial neoplasia grade in Thinprep cytological test and its significance.

    Science.gov (United States)

    Shi, Yong-Hua; Wang, Bo-Wei; Tuokan, Talaf; Li, Qiao-Zhi; Zhang, Ya-Jing

    2015-01-01

    A micronucleus is an additional small nucleus formed due to chromosomes or chromosomal fragments fail to be incorporated into the nucleus during cell division. In this study, we assessed the utility of micronucleus counting as a screening tool in cervical precancerous lesions in Thinprep cytological test smears under oil immersion. High risk HPV was also detected by hybrid capture-2 in Thinprep cytological test smears. Our results showed that micronucleus counting was significantly higher in high-grade squamous intraepithelial lesion (HSIL) and invasive carcinoma cases compared to low-grade squamous intraepithelial lesion (LSIL) and non-neoplastic cases. Receiver operating characteristic (ROC) curve analysis revealed that micronucleus counting possessed a high degree of sensitivity and specificity for identifying HSIL and invasive carcinoma. Cut-off of 7.5 for MN counting gave a sensitivity of 89.6% and a specificity of 66.7% (P = 0.024 and AUC = 0.892) for detecting HSIL and invasive carcinoma lesions. Multiple linear regression analysis showed that only HSIL and invasive cancer lesions not age, duration of marital life and number of pregnancy are significantly associated with MN counting. The positive rate of high risk HPV was distinctly higher in LSIL, HSIL and invasive cancer than that in non-neoplstic categories. In conclusions, MN evaluation may be viewed as an effective biomarker for cervical cancer screening. The combination of MN count with HPV DNA detection and TCT may serve as an effective means to screen precancerous cervical lesions in most developing nations.

  15. SFTG international collaborative study on in vitro micronucleus test. II. Using human lymphocytes

    NARCIS (Netherlands)

    Clare, M.G.; Lorenzon, G.; Akhurst, L.C.; Marzin, D.; Delft, J. van; Montero, R.; Botta, A.; Bertens, A.; Cinelli, S.; Thybaud, V.; Lorge, E.

    2006-01-01

    This study on the in vitro micronucleus assay, comprising 11 laboratories using human lymphocytes, was coordinated by an organizing committee supported by the SFTG (the French branch of the European Environmental Mutagen Society). Nine coded substances were assessed for their ability to induce micro

  16. Micronucleus test on Triturus carnifex as a tool for environmental biomonitoring.

    Science.gov (United States)

    Udroiu, I; Sgura, A; Vignoli, L; Bologna, M A; D'Amen, M; Salvi, D; Ruzza, A; Antoccia, A; Tanzarella, C

    2015-05-01

    The amphibian micronucleus test has been widely used during the last 30 years to test the genotoxic properties of several chemicals and as a tool for ecogenotoxic monitoring. The vast majority of these studies were performed on peripheral blood of urodelan larvae and anuran tadpoles and to a lesser extent adults were also used. In this study, we developed protocols for measuring micronuclei in adult shed skin cells and larval gill cells of the Italian crested newt (Triturus carnifex). Amphibians were collected from ponds in two protected areas in Italy that differed in their radon content. Twenty-three adult newts and 31 larvae were captured from the radon-rich pond, while 20 adults and 27 larvae were taken from the radon-free site. The animals were brought to the laboratory and the micronucleus test was performed on peripheral blood and shed skins taken from the adults and on larval gills. Samples from the radon-rich site showed micronucleus frequencies higher than those from the radon-free site and the difference was statistically significant in gill cells (P micronucleus assay that can be useful for environmental studies in situ.

  17. A cytogenetic study of nuclear power plant workers using the micronucleus-centromere assay.

    Science.gov (United States)

    Thierens, H; Vral, A; Barbé, M; Aousalah, B; De Ridder, L

    1999-09-15

    A cytogenetic study was performed in 215 nuclear power plant workers occupationally exposed to radiation using the micronucleus-centromere assay for peripheral blood lymphocytes. As control population served administrative staff with yearly doses below 1 mSv. The increase of the micronucleus frequency with age, observed in the non-smoking control population, is mainly due to an enhanced number of centromere-positive micronuclei, pointing to an increased chromosome loss. No differences in the number of micronuclei, centromere-positive and centromere-negative micronuclei between smokers and non-smokers are observed. An analysis of the micronucleus data vs. the dose accumulated over the 10 years preceding the venepuncture shows no significant clastogenic or aneuploidogenic effects of the exposure in the studied population which is representative for workers in the nuclear industry at present. According to the linear fits to our data an increase of the micronucleus frequency pro rata 0.5 per 1000 binucleated cells per year, related to the centromere-negative micronuclei, may be expected for workers with the maximal tolerable dose of 20 mSv/year.

  18. A Genome-Wide Association Study for Regulators of Micronucleus Formation in Mice

    Directory of Open Access Journals (Sweden)

    Rebecca E. McIntyre

    2016-08-01

    Full Text Available In mammals the regulation of genomic instability plays a key role in tumor suppression and also controls genome plasticity, which is important for recombination during the processes of immunity and meiosis. Most studies to identify regulators of genomic instability have been performed in cells in culture or in systems that report on gross rearrangements of the genome, yet subtle differences in the level of genomic instability can contribute to whole organism phenotypes such as tumor predisposition. Here we performed a genome-wide association study in a population of 1379 outbred Crl:CFW(SW-US_P08 mice to dissect the genetic landscape of micronucleus formation, a biomarker of chromosomal breaks, whole chromosome loss, and extranuclear DNA. Variation in micronucleus levels is a complex trait with a genome-wide heritability of 53.1%. We identify seven loci influencing micronucleus formation (false discovery rate <5%, and define candidate genes at each locus. Intriguingly at several loci we find evidence for sexual dimorphism in micronucleus formation, with a locus on chromosome 11 being specific to males.

  19. 900 MHz radiation does not induce micronucleus formation in different cell types.

    Science.gov (United States)

    Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Schrader, Thorsten; Stopper, Helga

    2012-07-01

    The exposure of the population to non-ionising electromagnetic radiation is still increasing, mainly due to mobile communication. Whether low-intensity electromagnetic fields can cause other effects apart from heating has been a subject of debate. One of the effects, which were proposed to be caused by mobile phone radiation, is the occurrence of mitotic disturbances. The aim of this study was to investigate possible consequences of these mitotic disturbances as manifest genomic damage, i.e. micronucleus induction. Cells were irradiated at a frequency of 900 MHz, which is located in one of the main frequency bands applied for mobile communication. Two cell types were used, HaCaT cells as human cells and A(L) cells (human-hamster hybrid cells), in which mitotic disturbances had been reported to occur. After different post-exposure incubation periods, cells were fixed and micronucleus frequencies were evaluated. Both cell types did not show any genomic damage after exposure. To adapt the protocol for the micronucleus test into the direction of the protocol for mitotic disturbances, the post-exposure incubation period was reduced and exposure time was extended to one cell cycle length. This did not result in any increase of the genomic damage. In conclusion, micronucleus induction was not observed as a consequence of exposure to non-ionising radiation, even though this agent was reported to cause mitotic disturbances under similar experimental conditions.

  20. Tradescantia-micronucleus (Trad-MCN) bioassay on clastogenicity of wastewater and in situ monitoring.

    Science.gov (United States)

    Ruiz, E F; Rabago, V M; Lecona, S U; Perez, A B; Ma, T H

    1992-11-01

    The Tradescantia-micronucleus (Trad-MCN) bioassay was used to determine the clastogenicity of wastewater samples collected from the Arena canal which contains effluent from the industrial district Benito Juarez of the city of Queretaro, Mexico. Fifteen wastewater samples which were collected, in most cases, at bi-weekly intervals beginning in September 1986 through February 1988, after a 3-fold dilution were used to treat Tradescantia plant cuttings. The clastogenicity expressed in terms of micronucleus frequencies of treated groups (30 h of treatment without recovery time) was significantly (0.01) higher than that of the tapwater control groups. The Trad-MCN bioassay was also used for in situ monitoring of air pollutants for the clastogenicity at 3 sites near the industrial and residential areas (Flores Magon, Conalep and Bellas Artes) of the city of Queretaro. Fourteen monitoring trips were made to each of the 3 sites at monthly intervals beginning in May 1988 through June 1990. Seasonal variation of micronucleus frequencies was exhibited with the peak clastogenicities shown in May and June 1988, June 1989 and April 1990 at the three sites. Micronucleus frequencies of all the exposed groups at the Conalep site, a predominantly industrial area, were markedly higher than that of the laboratory control groups throughout the 2-year period.

  1. Micronucleus Assay for Evaluation of Genotoxicity in Potentially Malignant and Malignant Disorders

    Directory of Open Access Journals (Sweden)

    Parvathi Devi

    2011-01-01

    Full Text Available Oral cancer is a common malignancy, ranking first among all cancers in Western and Asian countries. It is preceded by some benign lesions or conditions, which are termed precancerous. Only one-third of people at the precancerous stage of disease succumb to cancer, it would be of practical importance to identify individuals at risk among them. Biomarkers, instruments of individual tumor prevention, help to detect high-risk patents. The induction of micronucleus is considered to bean effective biomarker of diseases- In the recent past, a great deal of enthusiasm was raised by application of the micronucleus test to assess DNA damage in human population. The present study is aimed at the evaluation of frequency of micronuclei in smears of oral exfoliated cells. A total of 33 patients with potentially malignant (leukoplakia, OSMF, lichen planus and malignant oral epithelial diseases from the department of oral medicine and radiology were considered as study group and compared with 33 age and sex matched healthy controls. Micronucleus frequencies were found higher in diseased patients than in control subjects- Hence, concluded that the micronucleus assay can be used as a prognostic indicator in potentially malignant and malignant disorders.

  2. Tipping: Is it ever OK to skip the tip?

    National Research Council Canada - National Science Library

    N'dea Yancey-Bragg

    2017-01-01

    ..., the minimum wage for tipped workers can be also low as $2. 13. Delivery Apps like UberEats and Postmates don't require tips, although some offer suggested gratuities on their checkout page. (Uber on Tuesday just added the option to tip. ) Grubhub founder and CEO Matt Maloney strongly encourages a 10-15% tip. After all, delivery drivers aren't salaried work...

  3. Tip vorticity reduction and optimization of lifting surfaces

    NARCIS (Netherlands)

    Sparenberg, JA

    2001-01-01

    In linearized optimization theory, lifting surfaces, moving in an inviscid and incompressible fluid, shed tip vorticity of which the strength has infinite square-root singularities. Here we discuss that an optimization procedure can be coupled to constraints so that the strength of the shed vorticit

  4. Investigation of UWB Wind Turbine Blade Deflection Sensing with a Tip Antenna inside a Blade

    DEFF Research Database (Denmark)

    Zhang, Shuai; Jensen, Tobias Lindstrøm; Franek, Ondrej;

    2016-01-01

    An UWB blade deflection sensing system with a tip antenna inside a blade is investigated in this paper. The lower UWB band of 3.1-5.3 GHz is utilized. This system composes of two UWB radio links between one antenna inside the blade tip and two antennas outside the blade root. Blade deflections ar......, and the sensing system can realize the deflection tracking with a maximum deviation of 0.21 m and root mean squared error of 0.11 m.......An UWB blade deflection sensing system with a tip antenna inside a blade is investigated in this paper. The lower UWB band of 3.1-5.3 GHz is utilized. This system composes of two UWB radio links between one antenna inside the blade tip and two antennas outside the blade root. Blade deflections......-blade time-domain measurements are proposed to verify the simulations and realize the blade deflection sensing with an in-blade tip antenna. With the optimized in-blade tip antenna polarization and two root antenna locations, an accuracy of 2 cm is achieved for the tip-root antenna distance estimation...

  5. Dose-rate effects for apoptosis and micronucleus formation in gamma-irradiated human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Boreham, D.R.; Dolling, J.-A.; Maves, S.R. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Siwarungsun, N. [Chulalongkorn Univ., Bangkok (Thailand); Mitchel, R.E.J. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2000-07-01

    We have compared dose-rate effects for {gamma}-radiation-induced apoptosis and micronucleus formation in human lymphocytes. Long-term assessment of individual radiation-induced apoptosis showed little intraindividual variation but significant interindividual variation. The effectiveness of radiation exposure to cause apoptosis or micronucleus formation was reduced by low-dose-rate exposures, but the reduction was apparent at different dose rates for these two end points. Micronucleus formation showed a dose-rate effect when the dose rate was lowered to 0.29 cGy/min, but there was no accompanying cell cycle delay. A further increase in the dose-rate effect was seen at 0.15 cGy/min, but was now accompanied by cell cycle delay. There was no dose-rate effect for the induction of apoptosis until the dose rate was reduced to 0.15 cGy/min, indicating that the mechanisms or signals for processing radiation-induced lesions for these two end points must be different at least in part. There appear to be two mechanisms that contribute to the dose-rate effect for micronucleus formation. One of these does not affect binucleate cell frequency and occurs at dose rates higher than that required to produce a dose-rate effect for apoptosis, and one affects binucleate cell frequency, induced only at the very low dose rate which coincidentally produces a dose-rate effect for apoptosis. Since the dose rate at which cells showed reduced apoptosis as well as a further reduction in micronucleus formation was very low, we conclude that the processing of the radiation-induced lesions that induce apoptosis, and some micronuclei, is very slow in quiescent and PHA-stimulated lymphocytes, respectively. (author)

  6. Factors affecting the in vitro micronucleus assay for evaluation of nanomaterials.

    Science.gov (United States)

    Li, Yan; Doak, Shareen H; Yan, Jian; Chen, David H; Zhou, Min; Mittelstaedt, Roberta A; Chen, Ying; Li, Chun; Chen, Tao

    2017-01-01

    A number of in vitro methodologies have been used to assess the genotoxicity of different nanomaterials, including titanium dioxide nanoparticles (TiO2 NPs) and silver nanoparticles (AgNPs). The in vitro micronucleus assay is one of the most commonly used test methods for genotoxicity evaluation of nanomaterials. However, due to the novel features of nanomaterials, such as high adsorption capacity and fluorescence properties, there are unexpected interactions with experimental components and detection systems. In this study, we evaluate the interference by two nanoparticles, AgNPs and TiO2 NPs, with the in vitro micronucleus assay system and possible confounding factors affecting cytotoxicity and genotoxicity assessment of the nanomaterials including cell lines with different p53 status, nanoparticle coatings and fluorescence, cytochalasin B, fetal bovine serum in cell treatment medium and different measurement methodologies for detecting micronuclei. Our results showed that micronucleus induction by AgNPs was similar when evaluated using flow cytometry or microscope, whereas the induction by TiO2 NPs was different using the two methods due to TiO2's fluorescence interference with the cytometry equipment. Cells with the mutated p53 gene were more sensitive to micronucleus induction by AgNPs than the p53 wild-type cells. The presence of serum during treatment increased the toxicity of AgNPs. The coatings of nanoparticles played an important role in the genotoxicity of AgNPs. These collective data highlight the importance of considering the unique properties of nanoparticles in assessing their genotoxicity using the in vitro micronucleus assay.

  7. CYTOKINESIS-BLOCK MICRONUCLEUS ASSAY IN HUMAN GLIOMA CELLS EXPOSED TO RADIATION

    Directory of Open Access Journals (Sweden)

    Jerzy Slowinski

    2011-05-01

    Full Text Available Biological tests are efficient in reflecting the biological influences of several types of generally harmful exposures. The micronucleus assay is widely used in genotoxicity studies or studies on genomic damage in general. We present methodological aspects of cytokinesis-block micronucleus assay performed in human gliomas irradiated in vitro. Eight human glioblastoma cell lines obtained from DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Germany were gamma-irradiated (60Co over a dose range of 0-10 Gy. Cytokinesis-block micronucleus assay was performed to quantitate cytogenetic damage. The cells were fixed directly on dishes, stained with fluorochrome DAPI and evaluated under fluorescent and phase contrast microscope. The micronucleus frequency was expressed as a micronuclei (MN per binucleated cell (BNC ratio, calculated after scoring at least 100 BNC per dish. The frequency of spontaneous MN ranged from 0.17 to 0.613 (mean: 0.29 ± 0.14. After irradiation increase of MN frequency in the range of 0.312 - 2.241 (mean: 0.98 ± 0.68 was found at 10 Gy. Gliomas are extremely heterogenous in regard to cytogenetic effects of irradiation, as shown in this study by cytokinesis-block micronucleus assay. This test is easily performed on irradiated glioma cell lines and can assist in determining their radiosensitivity. However, in order to obtain reliable and reproducible results, precise criteria for MN scoring must be strictly followed. Simultaneous use of fluorescent and phase contrast equipment improves imaging of morphological details and can further optimize MN scoring.

  8. Automatic analysis of the micronucleus test in primary human lymphocytes using image analysis.

    Science.gov (United States)

    Frieauff, W; Martus, H J; Suter, W; Elhajouji, A

    2013-01-01

    The in vitro micronucleus test (MNT) is a well-established test for early screening of new chemical entities in industrial toxicology. For assessing the clastogenic or aneugenic potential of a test compound, micronucleus induction in cells has been shown repeatedly to be a sensitive and a specific parameter. Various automated systems to replace the tedious and time-consuming visual slide analysis procedure as well as flow cytometric approaches have been discussed. The ROBIAS (Robotic Image Analysis System) for both automatic cytotoxicity assessment and micronucleus detection in human lymphocytes was developed at Novartis where the assay has been used to validate positive results obtained in the MNT in TK6 cells, which serves as the primary screening system for genotoxicity profiling in early drug development. In addition, the in vitro MNT has become an accepted alternative to support clinical studies and will be used for regulatory purposes as well. The comparison of visual with automatic analysis results showed a high degree of concordance for 25 independent experiments conducted for the profiling of 12 compounds. For concentration series of cyclophosphamide and carbendazim, a very good correlation between automatic and visual analysis by two examiners could be established, both for the relative division index used as cytotoxicity parameter, as well as for micronuclei scoring in mono- and binucleated cells. Generally, false-positive micronucleus decisions could be controlled by fast and simple relocation of the automatically detected patterns. The possibility to analyse 24 slides within 65h by automatic analysis over the weekend and the high reproducibility of the results make automatic image processing a powerful tool for the micronucleus analysis in primary human lymphocytes. The automated slide analysis for the MNT in human lymphocytes complements the portfolio of image analysis applications on ROBIAS which is supporting various assays at Novartis.

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... risks? What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular ... bleeding from enlarged veins. top of page How is the procedure performed? Image-guided, minimally invasive procedures ...

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... code: Phone no: Thank you! Do you have a personal story about radiology? Share your patient story ...

  11. Academisch schrijven: Tips and tricks

    NARCIS (Netherlands)

    Wetzels, Sandra

    2012-01-01

    Wetzels, S. A. J. (2012, 14 April). Academisch schrijven: Tips and tricks [Academic writing: Tips and tricks]. Presentation at sprint meeting 'De praktijk van actief leren' from the master programme Learning Sciences, Eindhoven, The Netherlands.

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... or bypass, without the risks that accompany open surgery. TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS should have less of an effect ...

  13. Safety Tips: Baseball (For Parents)

    Science.gov (United States)

    ... Tips: Baseball KidsHealth > For Parents > Safety Tips: Baseball Print A A A What's in this article? Why Baseball Safety Is Important Gear Guidelines Breakaway Bases Before Starting the Game During Game Play Excessive Pitching A Few Other ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... a TIPS. top of page What are some common uses of the procedure? A TIPS is used ... or narrowing within the stent, which is less common with the current generation of GORE-TEX-lined ...

  15. Root Border Cells and Their Role in Plant Defense.

    Science.gov (United States)

    Hawes, Martha; Allen, Caitilyn; Turgeon, B Gillian; Curlango-Rivera, Gilberto; Minh Tran, Tuan; Huskey, David A; Xiong, Zhongguo

    2016-08-01

    Root border cells separate from plant root tips and disperse into the soil environment. In most species, each root tip can produce thousands of metabolically active cells daily, with specialized patterns of gene expression. Their function has been an enduring mystery. Recent studies suggest that border cells operate in a manner similar to mammalian neutrophils: Both cell types export a complex of extracellular DNA (exDNA) and antimicrobial proteins that neutralize threats by trapping pathogens and thereby preventing invasion of host tissues. Extracellular DNases (exDNases) of pathogens promote virulence and systemic spread of the microbes. In plants, adding DNase I to root tips eliminates border cell extracellular traps and abolishes root tip resistance to infection. Mutation of genes encoding exDNase activity in plant-pathogenic bacteria (Ralstonia solanacearum) and fungi (Cochliobolus heterostrophus) results in reduced virulence. The study of exDNase activities in plant pathogens may yield new targets for disease control.

  16. Study of the twinned dendrite tip shape II: Experimental assessment

    Energy Technology Data Exchange (ETDEWEB)

    Salgado-Ordorica, M.A., E-mail: mario.salgado@novelis.com [Laboratoire de Simulation des Materiaux LSMX, Ecole Polytechnique Federale de Lausanne, Station 12, 1015 Lausanne (Switzerland); Burdet, P.; Cantoni, M. [Centre Interdisciplinaire de Microscopie Electronique CIME, Ecole Polytechnique Federale de Lausanne, Station 12, 1015 Lausanne (Switzerland); Rappaz, M. [Laboratoire de Simulation des Materiaux LSMX, Ecole Polytechnique Federale de Lausanne, Station 12, 1015 Lausanne (Switzerland)

    2011-08-15

    The favorable growth kinetics of twinned dendrites can be explained by their complex morphology, multiple side branching mechanisms, growth undercooling and tip morphology. Three models were proposed for the twinned dendrite tip shape: (i) a grooved tip satisfying the Smith condition at the triple line; (ii) a doublon , i.e. a double-tip dendrite that grows with a narrow and deep liquid channel in its center; and (iii) a pointed (or edgy) tip, with consideration of the solid-liquid interfacial energy anisotropy. In the first part of this work, phase field simulations of half a twinned dendrite with an appropriate boundary condition to reproduce the Smith condition supported the doublon conjecture, with a narrow liquid channel ending its solidification with the formation of small liquid droplets. In this part, experimental observations of twinned dendrite tips reveal the presence of a small, but well-defined, groove, thus definitely eliminating the edged tip hypothesis. Focused ion beam nanotomography and energy-dispersive spectroscopy chemical analysis in a transmission electron microscope reveal the existence of a positive solute gradient in a region localized within 2 {mu}m around the twin plane. In Al-Zn specimens, small particles aligned within the twin plane further support the doublon conjecture and the predicted formation of small liquid droplets below the doublon root.

  17. Root hairs

    NARCIS (Netherlands)

    Grierson, C.; Nielsen, E.; Ketelaar, T.; Schiefelbein, J.

    2014-01-01

    Roots hairs are cylindrical extensions of root epidermal cells that are important for acquisition of nutrients, microbe interactions, and plant anchorage. The molecular mechanisms involved in the specification, differentiation, and physiology of root hairs in Arabidopsis are reviewed here. Root hair

  18. MES buffer affects Arabidopsis root apex zonation and root growth by suppressing superoxide generation in root apex

    Directory of Open Access Journals (Sweden)

    Tomoko eKagenishi

    2016-02-01

    Full Text Available In plants, growth of roots and root hairs is regulated by the fine cellular control of pH and reactive oxygen species. MES, 2-(N-morpholinoethanesulfonic acid as one of the Good’s buffers has broadly been used for buffering medium, and it is thought to suit for plant growth with the concentration at 0.1% (w/v because the buffer capacity of MES ranging pH 5.5-7.0 (for Arabidopsis, pH 5.8. However, many reports have shown that, in nature, roots require different pH values on the surface of specific root apex zones, namely meristem, transition zone and elongation zone. Despite the fact that roots always grow on a media containing buffer molecule, little is known about impact of MES on root growth. Here, we have checked the effects of different concentrations of MES buffer using growing roots of Arabidopsis thaliana. Our results show that 1% of MES significantly inhibited root growth, the number of root hairs and length of meristem, whereas 0.1% promoted root growth and root apex area (region spanning from the root tip up to the transition zone. Furthermore, superoxide generation in root apex disappeared at 1% of MES. These results suggest that MES disturbs normal root morphogenesis by changing the reactive oxygen species (ROS homeostasis in root apex.

  19. State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet

    Science.gov (United States)

    State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet (Presented by Dr. Marilyn J. Aardema, Chief Scientific Advisor, Toxicology, Dr. Leon Stankowski, et. al. (6/28/2012)

  20. Evaluation of mutagenic effects of formocresol: detection of DNA-protein cross-links and micronucleus in mouse bone marrow.

    Science.gov (United States)

    Ramos, Maria Emília Santos Pereira; Cavalcanti, Bruno Coêlho; Lotufo, Letícia Veras Costa; de Moraes, Manoel Odorico; Cerqueira, Eneida de Moraes Marcílio; Pessoa, Cláudia

    2008-03-01

    The genotoxic potential of formocresol was assessed by comet assay on human peripheral blood lymphocytes and in vivo micronucleus in mice. Peripheral blood lymphocytes, obtained from healthy donors, were exposed directly with different dilutions of formocresol for 45 minutes at 37 degrees C. To verify the possibility of formocresol to induce DNA-protein cross-links, treated lymphocytes were incubated with proteinase K. Micronucleus test was performed on male Swiss mice treated with several dilutions of formocresol by single intraperitoneal injection. After treatment, bone marrow was sampled 24 and 48 hours after formocresol administration. Formocresol did not produce detectable DNA damage as evaluated by comet assay. However, after proteinase K exposure, a dose-dependent increase of DNA migration was observed. Formocresol induced a significant increase in micronucleus frequencies at the highest dilution only at 24 hours after administration. Formocresol induced DNA-protein cross-links and an increased frequency of micronucleus.

  1. Seminal, adventitious and lateral root growth and physiological responses in rice to upland conditions

    Institute of Scientific and Technical Information of China (English)

    杨玲; 郑炳松; 毛传澡; 易可可; 吴运荣; 吴平; 陶勤南

    2003-01-01

    Understanding the growth and physiological responses of rice to upland conditions would be helpful for designing treatments to improve the tolerance of rice under a rainfed system. The objective of this study was to investigate the initiation,elongation and membrane stability of seminal, lateral and adventitious roots of upland rice after 9-d upland condition treatment. Compared with control roots under waterlogged conditions, upland water deficiency conditions favor seminal and lateral root growth over adventitious root growth by accelerating seminal root elongation, promoting lateral root initiation and elongation, and reducing the elongation and number of adventitious roots. Enhanced total root number and length resulted in increase of total root dry weight and thereby increasing the root-to-shoot ratio. Organic compound leakage from seminal root tips and adventitious roots increased progressively to some extent with upland culture duration, while significant increases in seminal root tips were the consequence of loss of membrane integrity caused by the upland-condition enhanced growth.

  2. Effect of biweekly shoot tip harvests on the growth and yield of Georgia Jet sweet potato grown hydroponically

    Science.gov (United States)

    Ogbuehi, Cyriacus R.; Loretan, Phil A.; Bonsi, C. K.; Hill, Walter A.; Morris, Carlton E.; Biswas, P. K.; Mortley, Desmond G.

    1989-01-01

    Sweet potato shoot tips have been shown to be a nutritious green vegetable. A study was conducted to determine the effect of biweekly shoot tip harvests on the growth and yield of Georgia Jet sweet potato grown in the greenhouse using the nutrient film technique (NFT). The nutrient solution consisted of a modified half Hoagland solution. Biweekly shoot tip harvests, beginning 42 days after planting, provided substantial amounts of vegetable greens and did not affect the fresh and dry foliage weights or the storage root number and fresh and dry storage root weights at final harvest. The rates of anion and cation uptake were not affected by tip harvests.

  3. 不结球白菜根尖体细胞染色体制片及其二倍体和四倍体有丝分裂过程观察%Chromosome preparation of somatic cell in root-tip of non-heading Chinese cabbage ( Brassica campestris ssp.chinensis ) and observation of mitosis process of its diploid and tetraploid

    Institute of Scientific and Technical Information of China (English)

    郑金双; 张蜀宁; 孙成振; 王雅美

    2011-01-01

    以不结球白菜(Brassica campestris ssp.chinensis Makino)根尖为材料,对染色体制片过程中根长(小于0.5 cm、0.5 ~ 1.0 cm、1.0~2.0 cm及大于2.0 cm)、预处理方法、预处理剂种类(2 mmol·L-1 8-羟基喹啉、2 mmol·L-1 8-羟基喹啉与质量浓度0.2g·L-1秋水仙素等体积混合液、质量浓度0.2g·L-1秋水仙素、饱和对二氯苯、质量浓度20或40 mg·L-1放线菌酮、质量浓度40mg·L-1放线菌酮与2 mmol·L-1 8-羟基喹啉等体积混合液)及预处理时间(1.0~3.5 h)进行了比较和筛选;在此基础上,对二倍体和四倍体不结球白菜根尖体细胞有丝分裂过程进行观察.结果表明:根长度对分裂相的数量有显著影响;根长1.0~2.0 cm,分裂相相对较多,占细胞总数的64.75%.冰冻预处理22 ~ 23 h,能获得一定量的分裂相.采用不同的预处理剂及预处理时间,分裂相的数量及染色体形态有明显差异;用质量浓度40 mg·L-1放线菌酮溶液处理3.5h,分裂相数量最多,但易导致染色体加倍;用质量浓度20mg·L-1放线菌酮预处理3.5h,染色体长且着丝点及随体清晰,且分裂相较多,占细胞总数的53.65%.因而,根长度以1.0 ~2.0 cm为宜,适宜的预处理方法为用质量浓度20 mg·L-1放线菌酮浸泡2.0~3.0 h.二倍体及四倍体不结球白菜根尖体细胞有丝分裂过程基本相似,在有丝分裂的间期、前期、中期、后期和末期染色体的行为基本一致,但在四倍体的有丝分裂过程中会出现多价体、染色体桥、落后染色体、染色体异常分离及内源有丝分裂等异常现象.%Using root-tip of non-heading Chinese cabbage (Brassica campestris ssp. Chinensis Makino) as experimental material, root length (shorter than 0.5 cm, 0.5-1.0 cm, 1.0-2.0 cm and longer than 2.0 cm) , pretreatment method, pretreatment agent types (2 mmol · L-1 8-hydroxyquinoline, equivalent volume mixed solution of 2 mmol · L-1 8-hydroxyquinoline and 0. 2 g

  4. Defoliation of strawberry mother plants for the production of runner tips

    Directory of Open Access Journals (Sweden)

    Miriane Dal Picio

    2014-07-01

    Full Text Available The objective of this work was to determine the sink-source relationships and their effects on the number and growth of runner tips of 'Camino Real' strawberry stock plants. Three types of sources were evaluated: one defoliation at 96 days after planting (DAP, two defoliations at 50 and 96 DAP, and mother plants without defoliation. Four types of sink were accessed: runner tips collected weekly and monthly, four stolons with rooted runner tips in pots, and four freely-grown stolons. A completely randomized experimental design was used in a split-plot arrangement, with four replicates. The source types were placed in the plots, and sink types in the subplots. The number of runner tips, the crown diameter, and the dry matter mass were determined. Number and growth of tips were higher on plants without defoliation, and decreased 44.7% on twice-defoliated mother plants. The two-defoliation management did not reduce runner tip dry matter mass only on plants with rooted stolons, which produced runner tips 50% heavier. Defoliation of mother plants bearing rooting stolons can be used to reduce their growth, without reducing the emission and growth of runner tips.

  5. Theoretical parametric study of the relative advantages of winglets and wing-tip extensions

    Science.gov (United States)

    Heyson, H. H.; Riebe, G. D.; Fulton, C. L.

    1977-01-01

    It was found that for identical increases in bending moment, a winglet provides a greater gain in induced efficiency than a tip extension. Winglet toe-in angle allows design trades between efficiency and root moment. A winglet showed the greatest benefit when the wing loads were heavy near the tip. Washout diminished the benefit of either tip modification, and the gain in induced efficiency became a function of lift coefficient; heavy wing loadings obtained the greatest benefit from a winglet, and low speed performance was enhanced even more than cruise performance. Both induced efficiency and bending moment increased with winglet length and outward cant. The benefit of a winglet relative to a tip extension was greatest for a nearly vertical winglet. Root bending moment was proportional to the minimum weight of bending material required in the wing; it is a valid index of the impact of tip modifications on a new wing design.

  6. Tipping point leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2003-04-01

    When William Bratton was appointed police commissioner of New York City in 1994, turf wars over jurisdiction and funding were rife and crime was out of control. Yet in less than two years, and without an increase in his budget, Bratton turned New York into the safest large city in the nation. And the NYPD was only the latest of five law-enforcement agencies Bratton had turned around. In each case, he succeeded in record time despite limited resources, a demotivated staff, opposition from powerful vested interests, and an organization wedded to the status quo. Bratton's turnarounds demonstrate what the authors call tipping point leadership. The theory of tipping points hinges on the insight that in any organization, fundamental changes can occur quickly when the beliefs and energies of a critical mass of people create an epidemic movement toward an idea. Bratton begins by overcoming the cognitive hurdles that block organizations from recognizing the need for change. He does this by putting managers face-to-face with operational problems. Next, he manages around limitations on funds, staff, or equipment by concentrating resources on the areas that are most in need of change and that have the biggest payoffs. He meanwhile solves the motivation problem by singling out key influencers--people with disproportionate power due to their connections or persuasive abilities. Finally, he closes off resistance from powerful opponents. Not every CEO has the personality to be a Bill Bratton, but his successes are due to much more than his personality. He relies on a remarkably consistent method that any manager looking to turn around an organization can use to overcome the forces of inertia and reach the tipping point.

  7. Arctic tipping points

    OpenAIRE

    Smolkova, Valentina

    2015-01-01

    The Arctic is warming much faster than the entire planet, and this causes severe melting of sea ice. However, the climate of different regions of the Earth is interconnected, and changes in the amount of ice in the Arctic can dramatically affect the climate across the whole planet. Some scientists claim that a possible tipping point is the event of the ice-free Arctic Ocean in summer. Certain predictions point towards ice-free Arctic summers around the year 2050, whereas others pre- dict this...

  8. Genotoxic effects of textile printing dye exposed workers in India detected by micronucleus assay.

    Science.gov (United States)

    Sellappa, Sudha; Prathyumnan, Shibily; Joseph, Shyn; Keyan, Kripa S; Balachandar, Vellingiri

    2010-01-01

    The textile printing industry in South India employs a great number of workers that may possibly be exposed to toxic compounds. In the present study, subjects from textile printing units were investigated for the presence of genetic damage in their peripheral blood lymphocytes using micronucleus assay. Proliferation was also investigated using a nuclear division index. It was found that the micronucleus frequency was considerably greater in exposed subjects than in non exposed control subjects, but division was not increased in a statistically significant way. For the time being, this investigation should be considered as a preliminary study in which the influence of potential confounders could be adequately assessed. However, our results are non-ambiguous, indicating a potential health risk in these workers.

  9. Maxillary incisor root resorption after rapid palatal expansion in Felis catus.

    Science.gov (United States)

    Vardimon, Alexander D; Levy, Thierry; Weinreb, Miron

    2005-02-01

    Root resorption after rapid palatal expansion (RPE) treatment was found in anchored teeth but has not been studied on non-anchored incisors. This study evaluated root resorption, root tipping, and root proximity of maxillary incisors after RPE treatment. Fourteen cats were divided into treated (n = 10) and untreated (n = 4) groups. The RPE treatment consisted of active, retention, and relapse phases, lasting 25, 60 and 60 d, respectively. Standardized occlusal radiographs were taken to measure tipping and root proximity before and after each treatment phase. Maxillary incisors were analysed histologically by fluorescent microscopy for root resorption. Data was analysed statistically with anova with repeated measures, t-test and Pearson's coefficient of correlation. Root resorption was confined to the first incisors and was 750-fold greater in the treated vs. the control group. Root tipping and root proximity were significantly greater (2.5- and 17-fold, respectively) in the first than in the second maxillary incisor and highly correlated with root resorption (r = -0.927 and 0.723, respectively). This suggests a cause (tipping and root proximity) and effect (root resorption) relationship. Data suggest that first maxillary incisor susceptibility to root resorption during RPE is associated with severe tipping and root proximity.

  10. [Progress of the micronucleus test in the field of molecular cancer epidemiology].

    Science.gov (United States)

    Xu, Huadong; Jia, Guang

    2015-01-01

    The micronucleus test (MNT) can be used to detect multiple genetic end points simultaneously, including chromosome aberration, mis-repaired DNA damage, apoptosis, parts of mutation and so on, which MNT has been an important part of the study of cancer epidemiology.Here, we reviewed the progress of MNT in the field of molecular cancer epidemiology in recent years, including early detection and diagnosis of cancer, evaluation of carcinogenic substances, genetic susceptibility biomarkers, micronutrient and cohort studies.

  11. Genotoxicity of silver nanoparticles evaluated using the Ames test and in vitro micronucleus assay.

    Science.gov (United States)

    Li, Yan; Chen, David H; Yan, Jian; Chen, Ying; Mittelstaedt, Roberta A; Zhang, Yongbin; Biris, Alexandru S; Heflich, Robert H; Chen, Tao

    2012-06-14

    Silver nanoparticles (AgNPs) have antimicrobial properties, which have contributed to their widespread use in consumer products. A current issue regarding nanomaterials is the extent to which existing genotoxicity assays are useful for evaluating the risks associated with their use. In this study, the genotoxicity of 5 nm AgNPs was assessed using two standard genotoxicity assays, the Salmonella reverse mutation assay (Ames test) and the in vitro micronucleus assay. Using the preincubation version of the Ames assay, Salmonella strains TA102, TA100, TA1537, TA98, and TA1535 were treated with 0.15-76.8 μg/plate of the AgNPs. Toxicity limited the doses that could be assayed to 2.4-38.4 μg/plate; no increases in mutant frequency over the vehicle control were found for the concentrations that could be assayed. Human lymphoblastoid TK6 cells were treated with 10-30 μg/ml AgNPs, and additional cells were treated with water and 0.73 gy X-rays as vehicle and positive controls. Micronucleus frequency was increased by the AgNP treatment in a dose-dependent manner. At a concentration of 30 μg/ml (with 45.4% relative population doubling), AgNPs induced a significant, 3.17-fold increase with a net increase of 1.60% in micronucleus frequency over the vehicle control, a weak positive response by our criteria. These results demonstrate that the 5 nm AgNP are genotoxic in TK6 cells. Also, the data suggest that the in vitro micronucleus assay may be more appropriate than the Ames test for evaluating the genotoxicity of the AgNPs.

  12. Adapted cytokinesis-block micronucleus assay (CBMn) for mouse embryonic stem cells

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Hamid Kalantari, Hamid Gourabi & Hossein Baharvand ### Abstract Our observation showed the addition of cytochalasin-B to mouse embryonic stem cells (mESC) culture for CBMn analysis led to the induction of apoptosis in these cells. On the other hand, addition of cyt-B is the most critical part of the cytokinesis-block micronucleus assay (CBMn) technique that cannot be omitted. Thus, modification of the traditional CBMn assay seems to be necessary. In this paper, we attempt...

  13. Analysis of resveratrol and radiation effects in lung cancer cells by micronucleus assay

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Carolina S.; Santos, Dymes R.A.; Vieira, Daniel P.; Rogero, Sizue O.; Rogero, Jose R., E-mail: carolina_sm@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sakuraba, Roberto K.; Weltman, Eduardo [Hospital Israelita Albert Einstein, Sao Paulo, SP (Brazil); Cruz, Aurea S.; Santos, Rezolina P. [Instituto Adolfo Lutz, Sao Paulo, SP (Brazil)

    2015-07-01

    Mucoepidermoid lung carcinoma is frequently manifested by obstructive trachea symptoms. Radiation and drugs combinations are commonly used in the lung cancer treatment. Currently there is a strong tendency to develop therapeutic strategies focused at the administration of high potential compounds to improve the ionizing radiation treatments, so as to increase the radiation effects on tumor cell while minimizing these effects to surrounding normal tissues. Resveratrol is a polyphenolic phytoalexin compound present in wines and several plants. This compound has a broad spectrum of biological activities such as antioxidant, anticarcinogenic, and induction of cell cycle arrest effects. Analysis of biological effects of ionizing radiation in the presence of resveratrol in different cell cultures has been the subject of many studies. To verify the genotoxic effects in cells exposed to ionizing radiation many methods have been proposed. The cytokinesis-block micronucleus technique is one of the preferred methods. The main of this study was to detect and quantify radioinduced DNA damage in mucoepidermoid lung carcinoma cells (NCI-H292) by cytokinesis-block micronucleus technique using cytocalasin-B. The cell culture was irradiated at a single fraction from a TrueBeam® linear accelerator (0, 0.8, 5, and 10 Gy), in the absence or presence of different resveratrol concentrations (0, 15, 30, and 60 μM). The results showed that resveratrol (15 and μM) induced significant increase frequency (p<0.05) of micronucleus formation in NCI-H292 cell culture non-irradiated and exposed at 5 Gy dose. Moreover, resveratrol (30 μM) induced micronucleus formation at 0.8 Gy dose. (author)

  14. Assessment of the genotoxicity of {sup 137}Cs radiation using Vicia-micronucleus, Tradescantia-micronucleus and Tradescantia-stamen-hair mutation bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Minouflet, Marion [Laboratoire Ecotoxicite et Sante Environnementale, CNRS FRE 2635, UFR Sci.F.A., Universite de Metz-Bridoux, rue du General Delestraint, F-57070 Metz (France)]. E-mail: marion.minouflet@terre.unige.ch; Ayrault, Sophie [Laboratoire Pierre Suee, CEA-CNRS, CEA Saclay, F-91191 Gif-sur-Yvette cedex (France); Badot, Pierre-Marie [Laboratoire de Biologie Environnementale, EA 3184 USC INRA, Universite de Franche-Comte, Place Leclerc, F-25030 Besancon cedex (France); Cotelle, Sylvie [Laboratoire Ecotoxicite et Sante Environnementale, CNRS FRE 2635, UFR Sci.F.A., Universite de Metz-Bridoux, rue du General Delestraint, F-57070 Metz (France); Ferard, Jean-Francois [Laboratoire Ecotoxicite et Sante Environnementale, CNRS FRE 2635, UFR Sci.F.A., Universite de Metz-Bridoux, rue du General Delestraint, F-57070 Metz (France)

    2005-07-01

    Since the middle of the 20th century, ionizing radiations from radioactive isotopes including {sup 137}Cs have been investigated to determine their genotoxic impact on living organisms. The present study was designed to compare the effectiveness of three plant bioassays to assess DNA damage induced by low doses of {sup 137}Cs: Vicia-micronucleus test (Vicia-MCN), Tradescantia-micronucleus test (Trad-MCN) and Tradescantia-stamen-hair mutation test (Trad-SH) were used. Vicia faba (broad bean) and Tradescantia clone 4430 (spiderwort) were exposed to {sup 137}Cs according to different scenarios: external and internal (contamination) irradiations. Experiments were conducted with various levels of radioactivity in solution or in soil, using solid or liquid {sup 137}Cs sources. The three bioassays showed different sensitivities to the treatments. Trad-MCN appeared to be the most sensitive test (significative response from 1.5 kBq/200 ml after 30 h of contamination). Moreover, at comparable doses, internal irradiations led to larger effects for the three bioassays. These bioassays are effective tests for assessing the genotoxic effects of radioactive {sup 137}Cs pollution.

  15. Assessment of the genotoxicity of 137Cs radiation using Vicia-micronucleus, Tradescantia-micronucleus and Tradescantia-stamen-hair mutation bioassays.

    Science.gov (United States)

    Minouflet, Marion; Ayrault, Sophie; Badot, Pierre-Marie; Cotelle, Sylvie; Ferard, Jean-François

    2005-01-01

    Since the middle of the 20th century, ionizing radiations from radioactive isotopes including 137Cs have been investigated to determine their genotoxic impact on living organisms. The present study was designed to compare the effectiveness of three plant bioassays to assess DNA damage induced by low doses of 137Cs: Vicia-micronucleus test (Vicia-MCN), Tradescantia-micronucleus test (Trad-MCN) and Tradescantia-stamen-hair mutation test (Trad-SH) were used. Vicia faba (broad bean) and Tradescantia clone 4430 (spiderwort) were exposed to 137Cs according to different scenarios: external and internal (contamination) irradiations. Experiments were conducted with various levels of radioactivity in solution or in soil, using solid or liquid 137Cs sources. The three bioassays showed different sensitivities to the treatments. Trad-MCN appeared to be the most sensitive test (significative response from 1.5 kBq/200 ml after 30 h of contamination). Moreover, at comparable doses, internal irradiations led to larger effects for the three bioassays. These bioassays are effective tests for assessing the genotoxic effects of radioactive 137Cs pollution.

  16. Micronucleus frequency is increased in peripheral blood lymphocytes of nuclear power plant workers.

    Science.gov (United States)

    Hadjidekova, Valeria B; Bulanova, Minka; Bonassi, Stefano; Neri, Monica

    2003-12-01

    Nuclear power plant workers are exposed to ionizing radiation at relatively low doses and for prolonged periods of time. To investigate the extent of genetic damage in these workers, a group of 133 nuclear power plant workers and 39 healthy controls were compared using the cytokinesis-block micronucleus assay. The frequency of micronuclei was significantly increased in peripheral lymphocytes of nuclear power plant workers (20.5 +/- 9.7% compared to 13.7 +/- 5.9%). A significant dose-response relationship was observed between micronucleus (MN) frequency and both the accumulated dose and the duration of employment (P < 0.01 for both variables after adjusting for age, gender and cigarette smoking) with an evident leveling off for exposures over 200 mSv. Accumulated dose and duration of employment were significantly correlated but exerted independent effects on MN frequency. For non-occupational parameters, age was significantly associated with the frequency of micronuclei, while gender was not. Smoking habit showed no overall effect, whereas increased chromosome damage was evident in smokers of more than 20 cigarettes per day. In conclusion, a dose-related association between MN frequency and exposure to ionizing radiation was evident in nuclear power plant workers, encouraging the application of the cytokinesis-block micronucleus assay in biomonitoring studies of human populations with prolonged exposure to ionizing radiation.

  17. Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

    Science.gov (United States)

    Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R

    2014-11-01

    Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard.

  18. Antigenotoxicity of artepillin C in vivo evaluated by the micronucleus and comet assays.

    Science.gov (United States)

    de Azevedo Bentes Monteiro Neto, Moacir; de Souza Lima, Ildercílio Mota; Furtado, Ricardo Andrade; Bastos, Jairo Kenupp; da Silva Filho, Ademar Alves; Tavares, Denise Crispim

    2011-11-01

    Artepillin C (3,5-diprenyl-p-coumaric acid), a major compound found in Brazilian green propolis and Baccharis dracunculifolia, shows anti-inflammatory, antibacterial, antiviral, antioxidant and antitumoral activities, among others. The aim of this study was to evaluate the genotoxic potential of artepillin C and its ability to prevent the chemically induced chromosome breakage or loss and the primary DNA damage using the micronucleus and comet assays in male Swiss mice, respectively. The animals were treated by gavage with different doses of artepillin C (0.4, 0.8 and 1.6 mg kg(-1) b.w.). For the antigenotoxicity assays, the different doses of artepillin C were administered simultaneously to doxorubicin (DXR; micronucleus test; 15 mg kg(-1) b.w.) and to methyl methanesulfonate (MMS; comet assay; 40 mg kg(-1) b.w.). The results showed that artepillin C itself was not genotoxic in the mouse micronucleus and comet assays. In the animals treated with artepillin C and DXR, the number of micronucleated reticulocytes was significantly lower in comparison with the animals treated only with DXR. Regarding antigenotoxicity, artepillin C at the tested doses significantly reduced the extent of DNA damage in liver cells induced by MMS.

  19. Tonoplast Aquaporins Facilitate Lateral Root Emergence1[OPEN

    Science.gov (United States)

    Hachez, Charles; Bienert, Manuela Désirée; Beebo, Azeez; Swarup, Kamal

    2016-01-01

    Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip mutants showed no or minor reduction in growth of the main root. This phenotype was due to the retardation of LRP emergence. Live cell imaging revealed that tight spatiotemporal control of TIP abundance in the tonoplast of the different LRP cells is pivotal to mediating this developmental process. While lateral root emergence is correlated to a reduction of AtTIP1;1 and AtTIP1;2 protein levels in LRPs, expression of AtTIP2;1 is specifically needed in a restricted cell population at the base, then later at the flanks, of developing LRPs. Interestingly, the LRP emergence phenotype of the triple tip mutants could be fully rescued by expressing AtTIP2;1 under its native promoter. We conclude that TIP isoforms allow the spatial and temporal fine-tuning of cellular water transport, which is critically required during the highly regulated process of LRP morphogenesis and emergence. PMID:26802038

  20. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  1. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed.......The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  2. A gradient of endogenous calcium forms in mucilage of graviresponding roots of Zea mays

    Science.gov (United States)

    Moore, R.; Fondren, W. M.

    1988-01-01

    Agar blocks that contacted the upper sides of tips of horizontally-oriented roots of Zea mays contain significantly less calcium (Ca) than blocks that contacted the lower sides of such roots. This gravity-induced gradient of Ca forms prior to the onset of gravicurvature, and does not form across tips of vertically-oriented roots or roots of agravitropic mutants. These results indicate that (1) Ca can be collected from mucilage of graviresponding roots, (2) gravity induces a downward movement of endogenous Ca in mucilage overlying the root tip, (3) this gravity-induced gradient of Ca does not form across tips of agravitropic roots, and (4) formation of a Ca gradient is not a consequence of gravicurvature. These results are consistent with gravity-induced movement of Ca being a trigger for subsequent redistribution of growth effectors (e.g. auxin) that induce differential growth and gravicurvature.

  3. A new strategy in root canal therapy: there is a lot going on in endodontic disinfection

    NARCIS (Netherlands)

    van der Waal, S.V.

    2015-01-01

    Apical periodontitis (AP) is the inflammatory response in the surrounding tissues at the root tip of a tooth to a microbial infection of the root canal system inside the tooth. AP can only resolve after thorough root canal disinfection. However at present, state-of-the-art root canal treatment does

  4. The Effect of Low Oxygen Stress on Phytophthora cinnamomi Infection and Disease of Cork Oak Roots

    Science.gov (United States)

    Karel A. Jacobs; James D. MacDonald; Alison M. Berry; Laurence R. Costello

    1997-01-01

    The incidence and severity of Phytophthora cinnamomi Rands root disease was quantified in cork oak (Quercus suber L.) roots subjected to low oxygen (hypoxia) stress. Seedling root tips were inoculated with mycelial plugs of the fungus and incubated in ≤1, 3-4, or 21 percent oxygen for 5 days. Ninety-four percent of roots...

  5. Complex Regulation of Prolyl-4-Hydroxylases Impacts Root Hair Expansion

    DEFF Research Database (Denmark)

    Velasquez, Silvia M; Ricardi, Martiniano M; Poulsen, Christian Peter

    2015-01-01

    Root hairs are single cells that develop by tip growth, a process shared with pollen tubes, axons, and fungal hyphae. However, structural plant cell walls impose constraints to accomplish tip growth. In addition to polysaccharides, plant cell walls are composed of hydroxyproline-rich glycoprotein...

  6. Gas only nozzle fuel tip

    Energy Technology Data Exchange (ETDEWEB)

    Bechtel, William Theodore (Scotia, NY); Fitts, David Orus (Ballston Spa, NY); DeLeonardo, Guy Wayne (Glenville, NY)

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozzle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  7. Root cap-dependent gravitropic U-turn of maize root requires light-induced auxin biosynthesis via the YUC pathway in the root apex

    Science.gov (United States)

    Suzuki, Hiromi; Yokawa, Ken; Nakano, Sayuri; Yoshida, Yuriko; Fabrissin, Isabelle; Okamoto, Takashi; Baluška, František; Koshiba, Tomokazu

    2016-01-01

    Gravitropism refers to the growth or movement of plants that is influenced by gravity. Roots exhibit positive gravitropism, and the root cap is thought to be the gravity-sensing site. In some plants, the root cap requires light irradiation for positive gravitropic responses. However, the mechanisms regulating this phenomenon are unknown. We herein report that maize roots exposed to white light continuously for ≥1–2h show increased indole-3-acetic acid (IAA) levels in the root tips, especially in the transition zone (1–3mm from the tip). Treatment with IAA biosynthesis inhibitors yucasin and l-kynurenine prevented any increases in IAA content and root curvature under light conditions. Analyses of the incorporation of a stable isotope label from tryptophan into IAA revealed that some of the IAA in roots was synthesized in the root apex. Furthermore, Zmvt2 and Zmyuc gene transcripts were detected in the root apex. One of the Zmyuc genes (ZM2G141383) was up-regulated by light irradiation in the 0–1mm tip region. Our findings suggest that IAA accumulation in the transition zone is due to light-induced activation of Zmyuc gene expression in the 0–1mm root apex region. Light-induced changes in IAA levels and distributions mediate the maize root gravitropic U-turn. PMID:27307546

  8. Effect of Coking Wastewater after Treatment with A2/O Process on Hereditary Stability in Maze Root Cells and Associated Oxidative Stress%A2/O工艺处理后焦化废水对玉米根尖细胞遗传稳定性的影响及其氧化损伤效应

    Institute of Scientific and Technical Information of China (English)

    郭振; 韩明; 桑楠

    2012-01-01

    Hydroponic experiment on maize with effluent of different volume concentrations coking wastewater was carried out. After the hydroponic experiment,the micronucleus rate of root tip. Antioxidant enzyme activities,the level of reactive oxygen species and oxidation products content of maize seedings were measured in order to explore the ecological risk of effluent and provide a theoretical basis to determine its biological monitoring indexes. The results showed that after treatment by different concentrations of effluent, the micronucleus rate of treated root tip and the content of H2O2,PCO,MDA in maize seedings increased significantly,the activities of POD and CAT increased also while the activity of SOD decreased. The results suggested that the coking wastewater contaminants are significantly reduced after treatment, but there is still certain ecological risk,this may be related with elevated levels of free radicals in plants.%用不同体积浓度生化出水对玉米进行水培试验,测定了处理后的玉米根尖细胞微核率、玉米幼苗抗氧化酶活性、活性氧水平以及氧化产物含量,目的在于探讨生化出水的生态风险性,并为其生物监控指标的确定提供一定的理论依据.结果表明,生化出水处理后,玉米根尖细胞微核率显著上升,玉米幼苗叶片中H2O2、PCO和MDA的含量明显增加,POD和CAT的活性升高,而SOD的活性却降低.这一结果提示,经过处理后的焦化废水其中污染物含量大幅降低,但其生态风险依然存在,这可能与植物体内自由基水平的升高有关.

  9. Developmental Characteristics and Cinnamic Acid Resistance of Root Border Cells in Cucumber and Figleaf Gourd Seedlings

    Institute of Scientific and Technical Information of China (English)

    QIAO Yong-xu; ZHANG Yong-ping; ZHANG Hong-xin; TIAN Yong-qiang; GAO Li-hong

    2013-01-01

    Root border cells (RBCs) originate from the root tip epidermis and surround the root apices. In this study, we evaluated the developmental characteristics and the roles of RBCs in protection of root apices of cucumber and ifgleaf gourd seedlings from CA toxicity. The formation of RBCs and the emergence of the root tip occurred almost simultaneously in root apices of cucumber and ifgleaf gourd seedlings. CA ranging from 0 to 0.25 mol L-1 inhibited root elongation and decreased root cell viability in the root tip, moreover the inhibitory effects of CA were more signiifcant in the CA-sensitive cucumber than in the CA-tolerant ifgleaf gourd. Removal of RBCs from root tips led to more severe CA induced inhibition of root elongation and decline in root cell viability. Increasing CA levels and treatment time decreased the relative viability of attached and detached RBCs. CA also induced a thicker mucilage layer surrounding attached RBCs of both species. Additionally, a signiifcantly higher relative cell viability of attached RBCs and thicker mucilage layers were observed in ifgleaf gourd. These results suggest that RBCs play an important role in protecting root tips from CA toxicity.

  10. Variability in micronucleus induction with different mutagens applied to several species of fish

    Directory of Open Access Journals (Sweden)

    Cesar Koppe Grisolia

    2000-03-01

    Full Text Available Fish are often used for screening genotoxicity of water. For such programs, a knowledge of the sensitivity to clastogens, spontaneous micronucleus frequency and cell cycle kinetics of the target tissue is necessary. To investigate the pattern of inter-specific sensitivity to micronucleus induction three species of fish, Tilapia rendalli, Oreochromis niloticus and Cyprinus carpio, were exposed to the clastogens bleomycin (BLM, cyclophosphamide (CP, 5-fluorouracil (5-FU, and mitomycin C (MMC. The binucleate/mononucleate ratio in peripheral erythrocytes exposed to cytochalasin B was also used to evaluate the time-dependent response of micronucleus formation during hematopoesis in the kidney and the micronucleus peak in peripheral erythrocytes. Micronucleus frequencies induced by CP were significantly greater than their respective controls for the three fish species throughout all treatment periods. During the whole evaluation period (30 days CP was also the most effective clastogen. In general, until the 14th day of evaluation period T. rendalii was the most sensitive species to clastogens. No difference in micronucleus frequencies among species was observed in the 4th evaluation (at the 30th day. A micronucleus peak was observed at the 7th day after treatment. After the 14th day the frequencies were stabilized. The cytochalasin B experiment was carried out to demonstrate that micronuclei induced in the young kidney erythrocyte cells were detected in the circulating blood 2-4 days later.Este estudo fez uma avaliação da indução de micronúcleos em eritrócitos de sangue periférico de peixes Tilapia rendalli, Oreochromis niloticus e Cyprinus carpio após o tratamento com mitomicina C, ciclofosfamida, 5-fluorouracil e bleomicina. Foram colhidas amostras periódicas de sangue com 2, 7, 14 e 30 dias após o tratamento único. Os tratamentos com citocalasina B tiveram como objetivo analisar as proporções entre células binucleadas

  11. An aquaporin PvTIP4;1 from Pteris vittata may mediate arsenite uptake.

    Science.gov (United States)

    He, Zhenyan; Yan, Huili; Chen, Yanshan; Shen, Hongling; Xu, Wenxiu; Zhang, Haiyan; Shi, Lei; Zhu, Yong-Guan; Ma, Mi

    2016-01-01

    The fern Pteris vittata is an arsenic hyperaccumulator. The genes involved in arsenite (As(III)) transport are not yet clear. Here, we describe the isolation and characterization of a new P. vittata aquaporin gene, PvTIP4;1, which may mediate As(III) uptake. PvTIP4;1 was identified from yeast functional complement cDNA library of P. vittata. Arsenic toxicity and accumulating activities of PvTIP4;1 were analyzed in Saccharomyces cerevisiae and Arabidopsis. Subcellular localization of PvTIP4;1-GFP fusion protein in P. vittata protoplast and callus was conducted. The tissue expression of PvTIP4;1 was investigated by quantitative real-time PCR. Site-directed mutagenesis of the PvTIP4;1 aromatic/arginine (Ar/R) domain was studied. Heterologous expression in yeast demonstrates that PvTIP4;1 was able to facilitate As(III) diffusion. Transgenic Arabidopsis showed that PvTIP4;1 increases arsenic accumulation and induces arsenic sensitivity. Images and FM4-64 staining suggest that PvTIP4;1 localizes to the plasma membrane in P. vittata cells. A tissue location study shows that PvTIP4;1 transcripts are mainly expressed in roots. Site-directed mutation in yeast further proved that the cysteine at the LE1 position of PvTIP4;1 Ar/R domain is a functional site. PvTIP4;1 is a new represented tonoplast intrinsic protein (TIP) aquaporin from P. vittata and the function and location results imply that PvTIP4;1 may be involved in As(III) uptake.

  12. Evaluation of a liver micronucleus assay in young rats (III): a study using nine hepatotoxicants by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Japanese Environmental Mutagen Society (JEMS)-Mammalian Mutagenicity Study Group (MMS).

    Science.gov (United States)

    Takasawa, Hironao; Suzuki, Hiroshi; Ogawa, Izumi; Shimada, Yasushi; Kobayashi, Kazuo; Terashima, Yukari; Matsumoto, Hirotaka; Aruga, Chinami; Oshida, Keiyu; Ohta, Ryo; Imamura, Tadashi; Miyazaki, Atsushi; Kawabata, Masayoshi; Minowa, Shigenori; Hayashi, Makoto

    2010-04-30

    We have been investigating a liver micronucleus assay to detect genotoxic chemicals using young rats for several years, and had established its advantages with respect to using autonomous proliferation of young rat hepatocytes. Nine chemicals known to induce hepatotoxic effects such as necrosis (2,6-dinitrotolune, bromobenzene, isoniazid, phenacetin, allyl alcohol and thioacetamide), cholestasis (chlorpromazine hydrochloride and alpha-naphthyl isothiocyanate) and oxidative stress (clofibrate) were selected for this study. A liver micronucleus assay was conducted in 4-week-old male F344 rats using two or three dose levels of test chemicals given orally by gavage to evaluate the compound's ability to induce micronucleated hepatocytes. Several of these test chemicals were additionally examined in a peripheral blood micronucleus assay conducted concurrently and in the same animals. The genotoxic rodent hepatocarcinogen, 2,6-dinitrotoluene showed a positive result in the liver micronucleus assay, but the nongenotoxic hepatocarcinogens, clofibrate and thioacetamide gave negative responses. Bromobenzene, known to produce DNA adducts but is noncarcinogenic in rodent liver, was judged equivocal in this assay. alpha-Naphthyl isothiocyanate is noncarcinogenic and showed negative response in the liver. The other four chemicals, known to be either noncarcinogenic or carcinogenic in other non-liver target organs, showed negative results in the liver micronucleus assay. Based on the results in the present study and previous report described above, it was concluded that this technique is able to effectively predict genotoxic rodent hepatocarcinogenicity, and does not give false positives due to hepatotoxicity.

  13. The role of root border cells in plant defense.

    Science.gov (United States)

    Hawes, M C; Gunawardena, U; Miyasaka, S; Zhao, X

    2000-03-01

    The survival of a plant depends upon the capacity of root tips to sense and move towards water and other nutrients in the soil. Perhaps because of the root tip's vital role in plant health, it is ensheathed by large populations of detached somatic cells - root 'border' cells - which have the ability to engineer the chemical and physical properties of the external environment. Of particular significance, is the production by border cells of specific chemicals that can dramatically alter the behavior of populations of soilborne microflora. Molecular approaches are being used to identify and manipulate the expression of plant genes that control the production and the specialized properties of border cells in transgenic plants. Such plants can be used to test the hypothesis that these unusual cells act as a phalanx of biological 'goalies', which neutralize dangers to newly generated root tissue as the root tip makes its way through soil.

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... encourage linking to this site. × Recommend RadiologyInfo to a friend Send to (friend's e-mail address): From ( ...

  15. Tips for Mental Health Interpretation

    Science.gov (United States)

    Whitsett, Margaret

    2008-01-01

    This paper offers tips for working with interpreters in mental health settings. These tips include: (1) Using trained interpreters, not bilingual staff or community members; (2) Explaining "interpreting procedures" to the providers and clients; (3) Addressing the stigma associated with mental health that may influence interpreters; (4) Defining…

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... What are the limitations of TIPS? What is a Transjugular Intrahepatic Portosystemic Shunt (TIPS)? A transjugular intrahepatic ... encourage linking to this site. × Recommend RadiologyInfo to a friend Send to (friend's e-mail address): From ( ...

  17. Stability of helical tip vortices in a rotor far wake

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær

    2007-01-01

    , corresponding to Rankine, Gaussian and Scully vortices, at radial extents ranging from the core radius of a tip vortex to several rotor radii. The analysis shows that the stability of tip vortices largely depends on the radial extent of the hub vorticity as well as on the type of vorticity distribution. As part......As a means of analysing the stability of the wake behind a multi-bladed rotor the stability of a multiplicity of helical vortices embedded in an assigned flow field is addressed. In the model the tip vortices in the far wake are approximated by infinitely long helical vortices with constant pitch...... and radius. The work is a further development of a model developed in Okulov (J. Fluid Mech., vol. 521, p. 319) in which the linear stability of N equally azimuthally spaced helical vortices was considered. In the present work the analysis is extended to include an assigned vorticity field due to root...

  18. Effect of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes.

    Science.gov (United States)

    Pongsavee, Malinee

    2015-01-01

    Sodium benzoate is food preservative that inhibits microbial growth. The effects of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes were studied. Sodium benzoate concentrations of 0.5, 1.0, 1.5, and 2.0 mg/mL were treated in lymphocyte cell line for 24 and 48 hrs, respectively. Micronucleus test, standard chromosome culture technique, PCR, and automated sequencing technique were done to detect micronucleus, chromosome break, and gene mutation. The results showed that, at 24- and 48-hour. incubation time, sodium benzoate concentrations of 1.0, 1.5, and 2.0 mg/mL increased micronucleus formation when comparing with the control group (P sodium benzoate concentrations of 2.0 mg/mL increased chromosome break when comparing with the control group (P Sodium benzoate did not cause Ala40Thr (GCG→ACG) in superoxide dismutase gene. Sodium benzoate had the mutagenic and cytotoxic toxicity in lymphocytes caused by micronucleus formation and chromosome break.

  19. Effect of Sodium Benzoate Preservative on Micronucleus Induction, Chromosome Break, and Ala40Thr Superoxide Dismutase Gene Mutation in Lymphocytes

    Directory of Open Access Journals (Sweden)

    Malinee Pongsavee

    2015-01-01

    Full Text Available Sodium benzoate is food preservative that inhibits microbial growth. The effects of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes were studied. Sodium benzoate concentrations of 0.5, 1.0, 1.5, and 2.0 mg/mL were treated in lymphocyte cell line for 24 and 48 hrs, respectively. Micronucleus test, standard chromosome culture technique, PCR, and automated sequencing technique were done to detect micronucleus, chromosome break, and gene mutation. The results showed that, at 24- and 48-hour. incubation time, sodium benzoate concentrations of 1.0, 1.5, and 2.0 mg/mL increased micronucleus formation when comparing with the control group (P<0.05. At 24- and 48-hour. incubation time, sodium benzoate concentrations of 2.0 mg/mL increased chromosome break when comparing with the control group (P<0.05. Sodium benzoate did not cause Ala40Thr (GCG→ACG in superoxide dismutase gene. Sodium benzoate had the mutagenic and cytotoxic toxicity in lymphocytes caused by micronucleus formation and chromosome break.

  20. Developmental characteristics and aluminum resistance of root border cells in rice seedlings.

    Science.gov (United States)

    Cai, MiaoZhen; Zhang, ShuNa; Xing, ChengHua; Wang, FangMei; Ning, Wang; Lei, Zhu

    2011-05-01

    The developmental characteristics of root border cells (RBCs) and their role in protection of root apices of rice seedling from Al toxicity were evaluated in two rice (Oryza sativa L.) cultivars differing in Al tolerance. Root elongation and RBCs viability were used as indicators for Al effects. The formation of RBCs and the emergence of the root tip occurred almost simultaneously. Treatment of the root with Al inhibited root elongation and increased Al accumulation in the root tips. Physical removal of RBCs from root tips resulted in a more severe inhibition of root elongation and a higher Al accumulation in the root tips. These effects were more pronounced in the Al-sensitive rice cultivar (II You 6216) than that in the Al-tolerant rice cultivar (II You 838). The relative viability of attached and detached RBCs decreased with increasing Al concentrations. Al also induced a thicker mucilage layer surrounding attached RBCs of both cultivars, and detached RBCs did not. Maintaining the abundant live RBCs encapsulated root tip and enhancing their mucilage secretion, appear to be important in alleviating Al toxicity and in allowing exclusion of Al from the rice root apex.

  1. The root cap: a short story of life and death.

    Science.gov (United States)

    Kumpf, Robert P; Nowack, Moritz K

    2015-09-01

    Over 130 years ago, Charles Darwin recognized that sensory functions in the root tip influence directional root growth. Modern plant biology has unravelled that many of the functions that Darwin attributed to the root tip are actually accomplished by a particular organ-the root cap. The root cap surrounds and protects the meristematic stem cells at the growing root tip. Due to this vanguard position, the root cap is predisposed to receive and transmit environmental information to the root proper. In contrast to other plant organs, the root cap shows a rapid turnover of short-lived cells regulated by an intricate balance of cell generation, differentiation, and degeneration. Thanks to these particular features, the root cap is an excellent developmental model system, in which generation, differentiation, and degeneration of cells can be investigated in a conveniently compact spatial and temporal frame. In this review, we give an overview of the current knowledge and concepts of root cap biology, focusing on the model plant Arabidopsis thaliana. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Role of Ascorbate in the Regulation of the Arabidopsis thaliana Root Growth by Phosphate Availability

    Directory of Open Access Journals (Sweden)

    Jarosław Tyburski

    2012-01-01

    Full Text Available Arabidopsis root system responds to phosphorus (P deficiency by decreasing primary root elongation and developing abundant lateral roots. Feeding plants with ascorbic acid (ASC stimulated primary root elongation in seedlings grown under limiting P concentration. However, at high P, ASC inhibited root growth. Seedlings of ascorbate-deficient mutant (vtc1 formed short roots irrespective of P availability. P-starved plants accumulated less ascorbate in primary root tips than those grown under high P. ASC-treatment stimulated cell divisions in root tips of seedlings grown at low P. At high P concentrations ASC decreased the number of mitotic cells in the root tips. The lateral root density in seedlings grown under P deficiency was decreased by ASC treatments. At high P, this parameter was not affected by ASC-supplementation. vtc1 mutant exhibited increased lateral root formation on either, P-deficient or P-sufficient medium. Irrespective of P availability, high ASC concentrations reduced density and growth of root hairs. These results suggest that ascorbate may participate in the regulation of primary root elongation at different phosphate availability via its effect on mitotic activity in the root tips.

  3. AH plus与氧化锌丁香油糊剂根尖封闭性能对比的Meta分析%Performance comparison of AH plus and zinc oxide clove oil paste root tip seal:a Meta-analysis

    Institute of Scientific and Technical Information of China (English)

    周倩妹; 李秀娥; 张琳; 严红; 刘玲; 吴君

    2016-01-01

    occurred after plus treatment of AH paste group which was lower than that in the control group [OR=0. 32, 95%CI(0. 26,0. 26), P<0. 01);AH plus paste group cure rate was higher than that of the control group after intervened 1 -2 years [ OR=2. 61, 95%CI(2. 03, 2. 03), P<0. 01];the paste resin class root filling AH plus length of root tip leakage was better than that of the control group, and nail polish and wax experiment method of measuring the penetration length of the tooth had statistical significance [MD=1. 28,95%CI( -1. 48,-1. 08), P<0. 01]; India ink staining solution to measure the penetration length of the tooth had statistical significance [MD=0. 82, 95% CI(-0. 90,-0. 74),P<0. 01]. Conclusions AH plus paste in root canal therapy can significantly alleviate pain, and the long-term curative effect is good, and better than biological intermiscibility, which is an ideal root canal filling material. Due to large incorporated in the analysis of the research and the quality difference, it is necessary for large sample, multicenter, randomized, double-blind, placebo-controlled trails to further confirm the clinical curative effect.

  4. Torsional Phacoemulsification and Tip Selection

    Directory of Open Access Journals (Sweden)

    Fırat Helvacıoğlu

    2014-10-01

    Full Text Available One of the recent advances in cataract surgery is torsional phacoemulsification. It was developed to increase the efficacy of ultrasonic emulsification. In torsional phacoemulsification, the torsional movement of the tip is translated to side-to-side cutting action with the aid of bent phaco tips. Lens material is cut in both directions, rather than only during a forward stroke. The efficiency of this technique is further enhanced by an improvement in followability provided by the inherent non-repulsive nature of the side-to-side motion. Tip selection is very important for the efficiency of torsional phacoemulsification. Theoretically, there are 2 ways to enhance the cutting efficiency of the tip. First is the stroke length; the 22-degree bent 30-degree Kelman mini-flared tip cuts longer than the 12-degree bent 30-degree mini-flared Kelman tip. Second is the angulation or bevel; the higher the degree (45 degrees, the better cutting efficiency. Retrospective analyses of the previously published clinical studies clearly demonstrated that the efficacy of the torsional phacoemulsification has positive correlation with both the aperture angles and neck angles of the tips. (Turk J Ophthalmol 2014; 44: 392-5

  5. Recommended protocols for the liver micronucleus test: Report of the IWGT working group.

    Science.gov (United States)

    Uno, Yoshifumi; Morita, Takeshi; Luijten, Mirjam; Beevers, Carol; Hamada, Shuichi; Itoh, Satoru; Ohyama, Wakako; Takasawa, Hironao

    2015-05-01

    At the 6th International Workshop on Genotoxicity Testing (IWGT), the liver micronucleus test working group discussed practical aspects of the in vivo rodent liver micronucleus test (LMNT). The group members focused on the three methodologies currently used, i.e., a partial hepatectomy (PH) method, a juvenile/young rat (JR) method, and a repeated-dose (RD) method in adult rodents. Since the liver is the main organ that metabolizes chemicals, the LMNT is expected to detect clastogens, especially those that need metabolic activation in the liver, and aneugens. Based on current data the three methods seem to have a high sensitivity and specificity, but more data, especially on non-genotoxic but toxic substances, would be needed to fully evaluate the test performance. The three methods can be combined with the micronucleus test (MNT) using bone marrow (BM) and/or peripheral blood (PB). The ability of the PH method to detect both clastogens and aneugens has already been established, but the methodology is technically challenging. The JR method is relatively straightforward, but animal metabolism might not be fully comparable to adult animals, and data on aneugens are limited. These two methods also have the advantage of a short testing period. The RD method is also straightforward and can be integrated into repeated-dose (e.g. 2 or 4 weeks) toxicity studies, but again data on aneugens are limited. The working group concluded that the LMNT could be used as a second in vivo test when a relevant positive result in in vitro mammalian cell genotoxicity tests is noted (especially under the condition of metabolic activation), and a negative result is observed in the in vivo BM/PB-MNT. The group members discussed LMNT protocols and reached consensus about many aspects of test procedures. However, data gaps as mentioned above remain, and further data are needed to fully establish the LMNT protocol.

  6. Cytogenetic biomonitoring in children with chronic tonsillitis: micronucleus frequency in exfoliated buccal epithelium cells.

    Science.gov (United States)

    Unal, Murat; Celik, Ayla; Ateş, Nurcan Aras; Micozkadioğlu, Deniz; Derici, Ebru; Pata, Yavuz Selim; Akbaş, Yücel

    2005-11-01

    To investigate the possible harmful cytogenetic effects associated with chronic tonsillitis by analyzing the micronucleus frequency and other nuclear abnormalities in exfoliated buccal epithelial cells. The study consisted of 20 children with chronic tonsillitis, and 20 control subjects with similar age and sex. The ages ranged between 5 and 12 years old (mean age: 7.5). The patients were diagnosed as having chronic tonsillitis on the basis of history, throat culture and clinical examinations. Buccal cell samples were collected with a wooden spatula. The samples were then applied to clean microscope slides. Smears were air dried and fixed in methanol:acetic acid. Then slides were stained by the Feulgen reaction technique. Three slides were prepared for each subject and 1000 cells were evaluated per slide to determine the frequencies of micronucleus and other nuclear abnormalities (binucleats, karyorrhexis and karyolysis). Statistically, Mann-Whitney U-test was used to analyze and compare the data. The mean micronucleus frequencies in patient and control groups were 5.29+/-1.67 and 1.58+/-0.33, respectively. In the patient group, mean binucleus, karyorrhexis and karyolysis frequencies were 3.13+/-1.2, 2.04+/-0.64, and 1.74+/-0.47, respectively. However, in the control group, mean binucleus, karyorrhexis and karyolysis frequencies were 1.43+/-0.47, 1.26+/-0.45, and 0.88+/-0.27, respectively. The mean frequencies of all parameters in the patient group were higher than the control values, and the difference was found to be statistically significant (pchildren with chronic tonsillitis could be under risk of significant cytogenetic damage.

  7. Ferrocenes as potential chemotherapeutic drugs: synthesis, cytotoxic activity, reactive oxygen species production and micronucleus assay.

    Science.gov (United States)

    Pérez, Wanda I; Soto, Yarelys; Ortíz, Carmen; Matta, Jaime; Meléndez, Enrique

    2015-02-01

    Three new ferrocene complexes were synthesized with 4-(1H-pyrrol-1-yl)phenol group appended to one of the Cp ring. These are: 1,1'-4-(1H-pyrrol-1-yl)phenyl ferrocenedicarboxylate, ('Fc-(CO2-Ph-4-Py)2'), 1,4-(1H-pyrrol-1-yl)phenyl, 1'-carboxyl ferrocenecarboxylate ('Fc-(CO2-Ph-4-Py)CO2H') and 4-(1H-pyrrol-1-yl)phenyl ferroceneacetylate ('Fc-CH2CO2-Ph-4-Py'). The new species were characterized by standard analytical methods. Cyclic voltammetry experiments showed that Fc-CH2CO2-Ph-4-Py has redox potential very similar to the Fc/Fc(+) redox couple whereas Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H have redox potentials of over 400 mV higher than Fc/Fc(+) redox couple. The in vitro studies on Fc-(CO2-Ph-4-Py)2 and Fc-(CO2-Ph-4-Py)CO2H revealed that these two compounds have moderate anti-proliferative activity on MCF-7 breast cancer cell line. In contrast Fc-CH2CO2-Ph-4-Py which displayed low anti-proliferative activity. In the HT-29 colon cancer cell line, the new species showed low anti-proliferative activity. Cytokinesis-block micronucleus assay (CBMN) was performed on these ferrocenes and it was determined they induce micronucleus formation on binucleated cells and moderate genotoxic effects on the MCF-7 breast cancer cell line. There is a correlation between the IC50 values of the ferrocenes and the amount of micronucleus formation activity on binucleated cells and the reactive oxygen species (ROS) production on MCF-7 cell line.

  8. Immobilization of aluminum with mucilage secreted by root cap and root border cells is related to aluminum resistance in Glycine max L.

    Science.gov (United States)

    Cai, Miaozhen; Wang, Ning; Xing, Chenghua; Wang, Fangmei; Wu, Kun; Du, Xing

    2013-12-01

    The root cap and root border cells (RBCs) of most plant species produced pectinaceous mucilage, which can bind metal cations. In order to evaluate the potential role of root mucilage on aluminum (Al) resistance, two soybean cultivars differing in Al resistance were aeroponic cultured, the effects of Al on root mucilage secretion, root growth, contents of mucilage-bound Al and root tip Al, and the capability of mucilage to bind Al were investigated. Increasing Al concentration and exposure time significantly enhanced mucilage excretion from both root caps and RBCs, decreased RBCs viability and relative root elongation except roots exposed to 400 μM Al for 48 h in Al-resistant cultivar. Removal of root mucilage from root tips resulted in a more severe inhibition of root elongation. Of the total Al accumulated in root, mucilage accounted 48-72 and 12-27 %, while root tip accounted 22-52 and 73-88 % in Al-resistant and Al-sensitive cultivars, respectively. A (27)Al nuclear magnetic resonance spectrum of the Al-adsorbed mucilage showed Al tightly bound to mucilage. Higher capacity to exclude Al in Al-resistant soybean cultivar is related to the immobilization and detoxification of Al by the mucilage secreted from root cap and RBCs.

  9. Assessment of micronucleus frequency in exfoliated buccal epithelial cells among fisher folks exposed to mine tailings in Marinduque Island, Philippines

    Institute of Scientific and Technical Information of China (English)

    Elena M Ragragio; Celeste P Belleza; Mark C Narciso; Glenn L Sia Su

    2010-01-01

    Objective:To evaluate the potential toxic effects of mine tailings exposure among the fisher folks residing near and far from the Calancan Bay, Marinduque, using the micronucleus assay as an endpoint.Methods: The fisher folks residing near and far from the Calancan Bay were interviewed and the presence and frequency of cells with micronucleus in exfoliated buccal epithelial cells were examined.Results: Results showed that the prevalence of cells with micronucleus was higher among the fisher folks who were directly exposed to the mine tailings as compared with those fisher folks who reside in a community without exposure of mine tailings and history of mining (P<0.05).Conclusions: The presence and the significant difference in the cells with micronuclei observed near the Calancan Bay could possibly indicate a prolonged chemical stress caused by the toxic heavy metals in the mine tailings and the environment.

  10. Do ectomycorrhizal and arbuscular mycorrhizal temperate tree species systematically differ in root order based fine root morphology and biomass?

    Directory of Open Access Journals (Sweden)

    Petra eKubisch

    2015-02-01

    Full Text Available While most temperate broad-leaved tree species form ectomycorrhizal (EM symbioses, a few species have arbuscular mycorrhizas (AM. It is not known whether EM and AM tree species differ systematically with respect to fine root morphology, fine root system size and root functioning. In a species-rich temperate mixed forest, we studied the fine root morphology and biomass of three EM and three AM tree species from the genera Acer, Carpinus, Fagus, Fraxinus and Tilia searching for principal differences between EM and AM trees. We further assessed the evidence of convergence or divergence in root traits among the six co-occurring species. Eight fine root morphological and chemical traits were investigated in root segments of the first to fourth root order in three different soil depths and the relative importance of the factors root order, tree species and soil depth for root morphology was determined. Root order was more influential than tree species while soil depth had only a small effect on root morphology All six species showed similar decreases in specific root length and specific root area from the 1st to the 4th root order, while the species patterns differed considerably in root tissue density, root N concentration, and particularly with respect to root tip abundance. Most root morphological traits were not significantly different between EM and AM species (except for specific root area that was larger in AM species, indicating that mycorrhiza type is not a key factor influencing fine root morphology in these species. The order-based root analysis detected species differences more clearly than the simple analysis of bulked fine root mass. Despite convergence in important root traits among AM and EM species, even congeneric species may differ in certain fine root morphological traits. This suggests that, in general, species identity has a larger influence on fine root morphology than mycorrhiza type.

  11. Micronucleus Test, Nuclear Abnormalities and Accumulation of Cu and Cd on Gambusia affinis (Baird & Girard, 1853)

    OpenAIRE

    Güner, Utku; Dilek, Fulya; Muranlı, Gökalp

    2011-01-01

    In the present work the induction of micronuclei (MNi) and nuclear abnormalities (NAs) in erythrocytes and Cu and Cd accumulation in whole body of Gambusia affinis were studied. Fish were exposed to two different Cu and Cd concentrations, 0.1 ppm and 1 ppm, for 1 and 2 weeks periods and to Cu-Cd combination (0.1 ppm Cu + 0.1 ppm Cd) for 2 weeks period using a semi-static renewal system. Micronucleus and nuclear abnormality analysis were carried out on peripheral blood erythrocytes. When fish...

  12. [The mutagenic and modifying properties of emoxipin studied by micronucleus assay in liver cells].

    Science.gov (United States)

    Uryvaeva, I V; Delone, G V; Smirnov, L D

    1996-01-01

    Emoxypin is a medicinal drug from the group of 3-oxypyridines. We studied the capacity of emoxypin to affect the spontaneous level of micronuclear aberrations in the hepatocytes (to decrease or increase it by exerting a mutagenic effect) using the micronucleus test, as well as the capacity to modulate (enhance or weaken) the effects of nitrosomethylurea and X-irradiation. The results obtained do not suggest cytogenetic activity of emoxypin. The nature of "spontaneous" micronuclear aberrations in the liver are discussed, as well as the causes of their age-related increase and adequacy of this model to search for antimutagens.

  13. Lead-induced DNA damage in Vicia faba root cells: Potential involvement of oxidative stress

    OpenAIRE

    Pourrut, Bertrand; Jean, Séverine; Silvestre, Jérôme; Pinelli, Eric

    2011-01-01

    Genotoxic effects of lead (0–20 µM) were investigated in whole-plant roots of Vicia faba L., grown hydroponically under controlled conditions. Lead-induced DNA damage in V. faba roots was evaluated by use of the comet assay, which allowed the detection of DNA strand-breakage and with the V. faba micronucleus test, which revealed chromosome aberrations. The results clearly indicate that lead induced DNA fragmentation in a dose-dependant manner with a maximum effect at 10 µM. In addition, at th...

  14. Scanning electron microscopic evaluation of root canal surfaces ...

    African Journals Online (AJOL)

    2014-07-15

    Jul 15, 2014 ... junction. Canal length was determined by placing a size 10 K-file. The working .... at the root tip of each tooth to prevent the flow of irrigants through ..... Sotokawa T. An analysis of clinical breakage of root canal instruments.

  15. Nitric oxide is involved in the oxytetracycline-induced suppression of root growth through inhibiting hydrogen peroxide accumulation in the root meristem

    Science.gov (United States)

    Yu, Qing-Xiang; Ahammed, Golam Jalal; Zhou, Yan-Hong; Shi, Kai; Zhou, Jie; Yu, Yunlong; Yu, Jing-Quan; Xia, Xiao-Jian

    2017-02-01

    Use of antibiotic-contaminated manure in crop production poses a severe threat to soil and plant health. However, few studies have studied the mechanism by which plant development is affected by antibiotics. Here, we used microscopy, flow cytometry, gene expression analysis and fluorescent dyes to study the effects of oxytetracycline (OTC), a widely used antibiotic in agriculture, on root meristem activity and the accumulation of hydrogen peroxide (H2O2) and nitric oxide (NO) in the root tips of tomato seedlings. We found that OTC caused cell cycle arrest, decreased the size of root meristem and inhibited root growth. Interestingly, the inhibition of root growth by OTC was associated with a decline in H2O2 levels but an increase in NO levels in the root tips. Diphenyliodonium (DPI), an inhibitor of H2O2 production, showed similar effects on root growth as those of OTC. However, exogenous H2O2 partially reversed the effects on the cell cycle, meristem size and root growth. Importantly, cPTIO (the NO scavenger) and tungstate (an inhibitor of nitrate reductase) significantly increased H2O2 levels in the root tips and reversed the inhibition of root growth by OTC. Out results suggest that OTC-induced NO production inhibits H2O2 accumulation in the root tips, thus leading to cell cycle arrest and suppression of root growth.

  16. Preservation of Disease-free Shoot Tips of Potato Germplasm through in vitro System

    Institute of Scientific and Technical Information of China (English)

    M K Biswas; M Hossain; R Islam

    2005-01-01

    The present investigation was undertaken to find out the best medium composition for medium-term preservation of disease free potato shoot tips in in vitro system. Thirteen potato genotypes and fourteen treatments were taken under consideration for the present experiment. Among fourteen treatments, mannitol and sorbitol containing media proved to be the best for medium-term preservation of potato shoot tips. High concentration of mannitol delayed root formation.

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... consist of a console containing a computer and electronics, a video display screen and a transducer that ... the placement of the TIPS stent, a contrast material will be injected in the hepatic vein to ...

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... in the chest or abdomen. This condition is most commonly seen in adults, often as a result ... minimally invasive procedures such as a TIPS are most often performed by a specially trained interventional radiologist ...

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... physician will numb an area just above your right collarbone with a local anesthetic . A very small ...

  20. Tips on writing by interview.

    Science.gov (United States)

    Piper, S

    1995-01-01

    Personal interviews add spice to publications--a well-written interview can inspire as well as inform. Here are 17 tips on writing by interview that will come in handy whether you are interviewing one person or several.

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... local anesthetic medications, general anesthesia or to contrast materials containing iodine (sometimes referred to as "dye" or " ... the placement of the TIPS stent, a contrast material will be injected in the hepatic vein to ...

  2. Search Tips: MedlinePlus

    Science.gov (United States)

    ... Tools Español You Are Here: Home → Search Tips URL of this page: https://medlineplus.gov/searchtips.html ... site by adding 'site:' and the domain or URL to your search words. For example, if you ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with cirrhosis. Tell your ... the liver into the veins of the spleen, stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... Patients who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal ... leading to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are ...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... of page What are some common uses of the procedure? A TIPS is used to treat the ... during the procedure. top of page What does the equipment look like? In this procedure, x-ray ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... portal vein to the hepatic vein in the liver. A small metal device called a stent is ... bowel back to the heart while avoiding the liver. TIPS may successfully reduce internal bleeding in the ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) Sponsored ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... TIPS in children is their tremendous variability in size, physiology, and medical diseases. This can result in ... Image Gallery Radiologist and patient consultation. View full size with caption Pediatric Content Some imaging tests and ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This page ... American College of Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise ...

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal vein ... vascular anatomy. top of page What will I experience during and after the procedure? Devices to monitor ...

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... functions properly. top of page Who interprets the results and how do I get them? Prior to ... TIPS is designed to produce the same physiological results as a surgical shunt or bypass, without the ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the ... skin that does not have to be stitched. Risks Any procedure where the skin is penetrated carries ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with cirrhosis. Tell your ... the liver into the veins of the spleen, stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... hepatic vein to identify the portal venous system. Access is then gained from the hepatic vein into ... TIPS procedure to make sure that it remains open and functions properly. top of page Who interprets ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... connect the portal vein to the hepatic vein in the liver. A small metal device called a ... the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with cirrhosis. ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... while avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients ... site. Using ultrasound, the doctor will identify your internal jugular vein , which is situated above your collarbone, ...

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... sends out high-frequency sound waves (that the human ear cannot hear) into the body and then ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ...

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening liver failure ... who already has encephalopathy because of their liver disease may not be a good candidate for the ...

  20. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... through the TIPS. Pressure will be applied to prevent any bleeding and the opening in the skin ... are monitored in intensive care beforehand and during recovery. You should be able to resume your normal ...

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with ... stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding and the accumulation of fluid in the chest ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... is removed with it during a transplant operation. Studies have shown that this procedure is successful in ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... Other possible complications of the procedure include: fever muscle stiffness in the neck bruising on the neck ... limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening liver failure ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... these links. About Us | Contact Us | FAQ | Privacy | Terms of Use | Links | Site Map Copyright © 2017 Radiological ...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, allergies and medications you’re taking. You ... with ascites or variceal bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... through the TIPS. Pressure will be applied to prevent any bleeding and the opening in the skin ... are monitored in intensive care beforehand and during recovery. You should be able to resume your normal ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... blood draining from the bowel back to the heart while avoiding the liver. TIPS may successfully reduce ... blood away from the liver back to the heart). A stent is then placed in this tunnel ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... hepatic vein to identify the portal venous system. Access is then gained from the hepatic vein into ... TIPS procedure to make sure that it remains open and functions properly. top of page Who interprets ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... of page What are some common uses of the procedure? A TIPS is used to treat the ... during the procedure. top of page What does the equipment look like? In this procedure, x-ray ...

  10. Tips to Prevent Mosquito Bites

    Science.gov (United States)

    Using the right insect repellent and other preventive actions can discourage mosquitoes from landing on you. Tips include removing mosquito habitats such as standing water, minimizing exposed skin, and staying indoors while mosquitoes are most active.

  11. No-Fad Diet Tips

    Science.gov (United States)

    ... When I Stop Smoking? Quitting Resources No-Smoking Confidence Assessment and Tips Frequently Asked Questions (FAQs) About ... inner strength to you. Use this image to boost your resolve whenever you need help in seeing ...

  12. AUXIN AND GROWTH OF EXCISED ROOTS OF Bryophyllum calycinum.

    Science.gov (United States)

    Robbins, W J; Hervey, A

    1969-10-01

    Exogenous auxin (alpha-naphthalene acetic acid, indole acetic acid, or 2,4-dichlorophenoxyacetic acid) was essential for the growth of single excised root tips of Bryophyllum calycinum in 50 ml of a mineral salt-sucrose medium supplemented with vitamins. Large inocula with a dry weight of 2.0 mg or more grew with no auxin added to the medium. Evidence for the synthesis of auxin by the excised roots grown from the larger inocula is presented. Leaching of auxin from single root tips cultivated in 15 or 50 ml of basal medium is considered to account for their failure to grow.

  13. Further development of the EpiDerm 3D reconstructed human skin micronucleus (RSMN) assay.

    Science.gov (United States)

    Mun, Greg C; Aardema, Marilyn J; Hu, Ting; Barnett, Brenda; Kaluzhny, Yulia; Klausner, Mitchell; Karetsky, Viktor; Dahl, Erica L; Curren, Rodger D

    2009-03-17

    The upcoming ban on testing of cosmetics in animals by the European Union's 7th Amendment to the Cosmetics Directive will require genotoxicity safety assessments of cosmetics ingredients and final formulations to be based primarily on in vitro genotoxicity tests. The current in vitro test battery produces an unacceptably high rate of false positives, and used by itself would effectively prevent the use and development of many ingredients that are actually safe for human use. To address the need for an in vitro test that is more predictive of genotoxicity in vivo, we have developed an in vitro micronucleus assay using a three-dimensional human reconstructed skin model (EpiDerm) that more closely mimics the normal dermal exposure route of chemicals. We have refined this model and assessed its ability to predict genotoxicity of a battery of chemicals that have been previously classified as genotoxins or non-genotoxins based on in vivo rodent skin tests. Our reconstructed skin micronucleus assay correctly identified 7 genotoxins and 5 non-genotoxins, demonstrating its potential to have a higher predictive value than currently available in vitro genotoxicity tests, and its utility as part of a comprehensive in vitro genotoxicity testing strategy.

  14. Hyperthermia-induced micronucleus formation in a human keratinocyte cell line

    Energy Technology Data Exchange (ETDEWEB)

    Hintzsche, Henning; Riese, Thorsten [Universitaet Wuerzburg, Institut fuer Pharmakologie und Toxikologie, Versbacher Str. 9, 97078 Wuerzburg (Germany); Stopper, Helga, E-mail: Stopper@toxi.uni-wuerzburg.de [Universitaet Wuerzburg, Institut fuer Pharmakologie und Toxikologie, Versbacher Str. 9, 97078 Wuerzburg (Germany)

    2012-10-15

    Elevated temperature can cause biological effects in vitro and in vivo. Many studies on effects of hypo- and hyperthermia have been conducted, but only few studies systematically investigated the formation of genomic damage in the micronucleus test in human cells in vitro as a consequence of different temperatures. In the present study, HaCaT human keratinocytes were exposed to different temperatures from 37 Degree-Sign C to 42 Degree-Sign C for 24 h in a regular cell culture incubator. Micronucleus frequency as a marker of genomic damage was elevated in a temperature-dependent and statistically significant manner. Apoptosis occurred at temperatures of 39 Degree-Sign C or higher. Cell proliferation was unaffected up to 40 Degree-Sign C and decreased at 41 Degree-Sign C and 42 Degree-Sign C. Expression of the heat shock protein Hsp70 was elevated, particularly at temperatures of 40 Degree-Sign C and higher. These findings are in agreement with several in vivo studies and some in vitro studies looking at single, specific temperatures, but a systematically investigated temperature-dependent increase of genomic damage in human keratinocytes in vitro is demonstrated for the first time here.

  15. Origanum majorana Essential Oil Lacks Mutagenic Activity in the Salmonella/Microsome and Micronucleus Assays

    Directory of Open Access Journals (Sweden)

    Andrea dos Santos Dantas

    2016-01-01

    Full Text Available The present study aimed to investigate the in vitro mutagenic activity of Origanum majorana essential oil. The most abundant compounds identified by GC-MS were γ-terpinene (25.73%, α-terpinene (17.35%, terpinen-4-ol (17.24%, and sabinene (10.8%. Mutagenicity was evaluated by the Salmonella/microsome test using the preincubation procedure on TA98, TA97a, TA100, TA102, and TA1535 Salmonella typhimurium strains, in the absence or in the presence of metabolic activation. Cytotoxicity was detected at concentrations higher than 0.04 μL/plate in the absence of S9 mix and higher than 0.08 μL/plate in the presence of S9 mix and no gene mutation increase was observed. For the in vitro mammalian cell micronucleus test, V79 Chinese hamster lung fibroblasts were used. Cytotoxicity was only observed at concentrations higher than or equal to 0.05 μg/mL. Moreover, when tested in noncytotoxic concentrations, O. majorana essential oil was not able to induce chromosome mutation. The results from this study therefore suggest that O. majorana essential oil is not mutagenic at the concentrations tested in the Salmonella/microsome and micronucleus assays.

  16. Fluorescent dye-based simple staining for in vivo micronucleus test with flow cytometer.

    Science.gov (United States)

    Harada, Asako; Matsuzaki, Kaori; Takeiri, Akira; Tanaka, Kenji; Mishima, Masayuki

    2013-03-18

    Flow cytometry (FCM) has become known as a useful tool for examining numerous cells in a micronucleus test in a short time. To successfully count micronuclei, immature erythrocytes and micronuclei need to be specifically stained and CD71-based FCM, with anti-CD71 antibody for immature erythrocytes and propidium iodide (PI) for micronuclei is a widely accepted tool. Because staining with fluorescent dyes may be much simpler compared to immunostaining, attempts are being made to develop a fluorescent dye-based FCM (FD-FCM). The aim of this study was to provide a practical FD-FCM method. Peripheral blood (PB) erythrocytes and bone marrow (BM) erythrocytes were obtained from rats treated with cyclophosphamide at a dose of 20mg/kg for two days. Nucleic cells of BM samples were eliminated using a cellulose column. Then erythrocytes were fixed, stained with Hoechst 33258 and PI and examined with FCM. Mean FD-FCM values of micronucleated immature erythrocytes in PB and BM were respectively 110% and 77% of the values obtained by microscopy. Percentages of mean immature erythrocyte values by FCM to those by microscopy were 74% and 94%. These data suggest that the simple method, composed of column purification of erythrocytes, methanol fixation, fluorescent dye staining and FCM, was useful for automated scoring in micronucleus testing of rat BM and PB.

  17. Origanum majorana Essential Oil Lacks Mutagenic Activity in the Salmonella/Microsome and Micronucleus Assays

    Science.gov (United States)

    Klein-Júnior, Luiz Carlos; Guecheva, Temenouga N.; dos Santos, Luciana D.; Zanette, Régis A.; de Mello, Fernanda B.; de Mello, João Roberto Braga

    2016-01-01

    The present study aimed to investigate the in vitro mutagenic activity of Origanum majorana essential oil. The most abundant compounds identified by GC-MS were γ-terpinene (25.73%), α-terpinene (17.35%), terpinen-4-ol (17.24%), and sabinene (10.8%). Mutagenicity was evaluated by the Salmonella/microsome test using the preincubation procedure on TA98, TA97a, TA100, TA102, and TA1535 Salmonella typhimurium strains, in the absence or in the presence of metabolic activation. Cytotoxicity was detected at concentrations higher than 0.04 μL/plate in the absence of S9 mix and higher than 0.08 μL/plate in the presence of S9 mix and no gene mutation increase was observed. For the in vitro mammalian cell micronucleus test, V79 Chinese hamster lung fibroblasts were used. Cytotoxicity was only observed at concentrations higher than or equal to 0.05 μg/mL. Moreover, when tested in noncytotoxic concentrations, O. majorana essential oil was not able to induce chromosome mutation. The results from this study therefore suggest that O. majorana essential oil is not mutagenic at the concentrations tested in the Salmonella/microsome and micronucleus assays. PMID:27891531

  18. Effects of estradiol and progesterone on the variability of the micronucleus assay

    Energy Technology Data Exchange (ETDEWEB)

    Baeyens, Ans [Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, L. Pasteurlaan 2, 9000 Gent (Belgium)]. E-mail: ansbaeyens@hotmail.com; Vandersickel, Veerle [Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, L. Pasteurlaan 2, 9000 Gent (Belgium); Thierens, Hubert [Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, L. Pasteurlaan 2, 9000 Gent (Belgium); Ridder, Leo De [Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, L. Pasteurlaan 2, 9000 Gent (Belgium); Vral, Anne [Department of Anatomy, Embryology, Histology and Medical Physics, Ghent University, L. Pasteurlaan 2, 9000 Gent (Belgium)

    2005-10-15

    To investigate chromosomal radiosensitivity of lymphocytes the micronucleus (MN) assay has been used for many years. The results of these studies suggest the use of the MN assay as a biomarker for cancer predisposition. However, the MN assay has still some limitations associated with the reproducibility and sensitivity. Especially a high intra-individual variability has been observed. An explanation for this high intra-individual variability is not yet available. In literature it is suggested that the high variability among females is attributable to hormonal status. In this study we investigated if the high intra-individual variability in micronucleus formation in lymphocytes of females after in vitro exposure to ionising radiation is caused by variations in hormone levels of estradiol (E2) and progesterone (PROG). For this, the MN assay was performed on blood samples of 18 healthy women during 7 consecutive weeks while the estradiol and progesterone levels were determined at the same time. The MN assay was also examined in cultures of isolated blood lymphocytes with estradiol or progesterone levels added in vitro. The results demonstrated that estradiol and progesterone levels have no influence on the variations in radiation-induced MN yields observed in blood samples of healthy women. These conclusions were confirmed by the 'in vitro' experiments as no correlation between the MN yields and the concentrations of hormones (estradiol or progesterone) added in vitro to isolated lymphocytes cultures was observed.

  19. Tradescantia micronucleus test indicates genotoxic potential of traffic emissions in European cities

    Energy Technology Data Exchange (ETDEWEB)

    Klumpp, Andreas [Institute for Landscape and Plant Ecology (320), University of Hohenheim, 70593 Stuttgart (Germany)]. E-mail: aklumpp@uni-hohenheim.de; Ansel, Wolfgang [Institute for Landscape and Plant Ecology (320), University of Hohenheim, 70593 Stuttgart (Germany); Klumpp, Gabriele [Institute for Landscape and Plant Ecology (320), University of Hohenheim, 70593 Stuttgart (Germany); Calatayud, Vicent [Fundacion CEAM, Parque Tecnologico, c/Charles Darwin 14, 46980 Paterna, Valencia (Spain); Garrec, Jean Pierre [INRA Nancy, Laboratoire Pollution Atmospherique, 54280 Champenoux (France); He Shang [INRA Nancy, Laboratoire Pollution Atmospherique, 54280 Champenoux (France); Penuelas, Josep [Unitat Ecofisiologia CSIC-CEAB-CREAF, Universitat Autonoma de Barcelona, Ed. C, 08193 Bellaterra, Barcelona (Spain); Ribas, Angela [Unitat Ecofisiologia CSIC-CEAB-CREAF, Universitat Autonoma de Barcelona, Ed. C, 08193 Bellaterra, Barcelona (Spain); Ro-Poulsen, Helge [Botanical Institute, University of Copenhagen, Oster Farimagsgade 2D, 1353 Copenhagen K (Denmark); Rasmussen, Stine [Botanical Institute, University of Copenhagen, Oster Farimagsgade 2D, 1353 Copenhagen K (Denmark); Sanz, Maria Jose [Fundacion CEAM, Parque Tecnologico, c/Charles Darwin 14, 46980 Paterna, Valencia (Spain); Vergne, Phillippe [ENS Lyon and Lyon Botanical Garden, 46 Allee d' Italie, 69364 Lyon Cedex 07 (France)

    2006-02-15

    Urban atmospheres contain complex mixtures of air pollutants including mutagenic and carcinogenic substances such as benzene, diesel soot, heavy metals and polycyclic aromatic hydrocarbons. In the frame of a European network for the assessment of air quality by the use of bioindicator plants, the Tradescantia micronucleus (Trad-MCN) test was applied to examine the genotoxicity of urban air pollution. Cuttings of Tradescantia clone no. 4430 were exposed to ambient air at 65 monitoring sites in 10 conurbations employing a standardised methodology. The tests revealed an elevated genotoxic potential mainly at those urban sites which were exposed to severe car traffic emissions. This bioassay proved to be a suitable tool to detect local 'hot spots' of mutagenic air pollution in urban areas. For its use in routine monitoring programmes, however, further standardisation of cultivation and exposure techniques is recommended in order to reduce the variability of results due to varying environmental conditions. - The Tradescantia micronucleus test can be used to assess genotoxic potential at urban sites.

  20. Best practices for application of attachment cells to in vitro micronucleus assessment by flow cytometry.

    Science.gov (United States)

    Bemis, Jeffrey C; Bryce, Steven M; Nern, Marlies; Raschke, Marian; Sutter, Andreas

    2016-01-01

    This work seeks to provide users with guidance on cell culture, treatment, processing and analytical conditions for achieving optimal performance of the in vitro micronucleus assay using the In Vitro MicroFlow(®) method. Experimental data are provided to support the advice described. The information provided covers specific topics or issues that are identified as critical to the methodology and thus is meant to work with instruction manuals, published papers and other references, and not as a replacement for these documents. The content is divided into several sections. Cell culture and treatment describes conditions for routine maintenance of cells as well as treatment with test articles. Preparation and processing of samples details steps found to be critical in execution of the procedure. Instrument parameters and analysis covers set-up of the flow cytometer and evaluation of the samples. General assay considerations and interpretation of results describes examination of data in terms of assay validity, viability and genotoxicity assessment. The goal is to educate users and enable them to design, conduct and interpret flow cytometric in vitro micronucleus (MN) studies. Readers should obtain an understanding of specific cell culture practices, options for assay formatting and execution and the information required to successfully integrate and validate the in vitro MN assay into their existing safety program.

  1. Gravitropic response of adventitious roots cultivated in light and darkness on sucrose-free medium.

    Science.gov (United States)

    Vinterhalter, D V; Vinterhalter, B S

    1999-11-30

    Elongation of adventitious roots of Dracaena fragrans was investigated under photoautotrophic conditions. Root elongation decreased and stopped when cultures were transferred to darkness. Upon return to light roots renewed growth after a 5 day lag period. During the first two days of intensive new growth roots were agravitropic elongating in random directions. Investigation showed that transient absence of geotropic response was connected with disappearance of starch grains in root tip which occurred due to sucrose starvation of cultures in continuous darkness.

  2. In vivo imaging of the tonoplast intrinsic protein family in Arabidopsis roots

    Directory of Open Access Journals (Sweden)

    Khonsari Roman H

    2009-11-01

    Full Text Available Abstract Background Tonoplast intrinsic proteins (TIPs are widely used as markers for vacuolar compartments in higher plants. Ten TIP isoforms are encoded by the Arabidopsis genome. For several isoforms, the tissue and cell specific pattern of expression are not known. Results We generated fluorescent protein fusions to the genomic sequences of all members of the Arabidopsis TIP family whose expression is predicted to occur in root tissues (TIP1;1 and 1;2; TIP2;1, 2;2 and 2;3; TIP4;1 and expressed these fusions, both individually and in selected pairwise combinations, in transgenic Arabidopsis. Analysis by confocal microscopy revealed that TIP distribution varied between different cell layers within the root axis, with extensive co-expression of some TIPs and more restricted expression patterns for other isoforms. TIP isoforms whose expression overlapped appeared to localise to the tonoplast of the central vacuole, vacuolar bulbs and smaller, uncharacterised structures. Conclusion We have produced a comprehensive atlas of TIP expression in Arabidopsis roots, which reveals novel expression patterns for not previously studied TIPs.

  3. Negative phototropism of rice root and its influencing factors

    Institute of Scientific and Technical Information of China (English)

    WANG; Zhong(王忠); MO; Yiwei(莫亿伟); QIAN; Shanqin(钱善勤); GU; Yunjie(顾蕴洁)

    2002-01-01

    Some characteristics of the rice (Oryza sativa L.) root were found in the experiment of unilaterally irradiating the roots which were planted in water: (ⅰ) All the seminal roots, adventitious roots and their branched roots bent away from light, and their curvatures ranged from 25° to 60°. The curvature of adventitious root of the higher node was often larger than that of the lower node, and even larger than that of the seminal root. (ⅱ) The negative phototropic bending of the rice root was mainly due to the larger growth increment of root-tip cells of the irradiated side compared with that of the shaded side. (ⅲ) Root cap was the site of light perception. If root cap was shaded while the root was irradiated the root showed no negative phototropism, and the root lost the characteristic of negative phototropism when root cap was divested. Rice root could resume the characteristic of negative phototropism when the new root cap grew up, if the original cells of root cap were well protected while root cap was divested. (ⅳ) The growth increment and curvature of rice root were both influenced by light intensity. Within the range of 0-100μmol@m-2@s-1, the increasing of light intensity resulted in the decreasing of the growth increment and the increasing of the curvature of rice root. (ⅴ) The growth increment and the curvature reached the maximum at 30℃ with the temperature treatment of 10-40℃. (ⅵ) Blue-violet light could prominently induce the negative phototropism of rice root, while red light had no such effect. (ⅶ) The auxin (IAA) in the solution, as a very prominent influencing factor, inhibited the growth, the negative phototropism and the gravitropism of rice root when the concentration of IAA increased. The response of negative phototropism of rice root disappeared when the concentration of IAA was above 10 mg@L-1.

  4. Influence of electrical fields and asymmetric application of mucilage on curvature of primary roots of Zea mays

    Science.gov (United States)

    Marcum, H.; Moore, R.

    1990-01-01

    Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl2, but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that 1) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast.

  5. Influence of electrical fields and asymmetric application of mucilage on curvature of primary roots of Zea mays

    Science.gov (United States)

    Marcum, H.; Moore, R.

    1990-01-01

    Primary roots of Zea mays cv. Yellow Dent growing in an electric field curve towards the anode. Roots treated with EDTA and growing in electric field do not curve. When root cap mucilage is applied asymmetrically to tips of vertically-oriented roots, the roots curve toward the mucilage. Roots treated with EDTA curve toward the side receiving mucilage and toward blocks containing 10 mM CaCl2, but not toward "empty" agar blocks or the cut surfaces of severed root tips. These results suggest that 1) free calcium (Ca) is necessary for root electrotropism, 2) mucilage contains effector(s) that induce gravitropiclike curvature, and 3) mucilage can replace gravitropic effectors chelated by EDTA. These results are consistent with the hypothesis that the downward movement of gravitropic effectors to the lower sides of tips of horizontally-oriented roots occurs at least partially in the apoplast.

  6. A novel soybean intrinsic protein gene, GmTIP2;3, involved in responding to osmotic stress

    Directory of Open Access Journals (Sweden)

    Da Yong eZhang

    2016-01-01

    Full Text Available Water is essential for plant growth and development. Water deficiency leads to loss of yield and decreased crop quality. To understand water transport mechanisms in plants, we cloned and characterized a novel tonoplast intrinsic protein (TIP gene from soybean with the highest similarity to TIP2-type from other plants, thus designated GmTIP2;3. The protein sequence contains two conserved NPA motifs and six transmembrane domains. The expression analysis indicated that this gene was constitutively expressed in all detected tissues, with higher levels in the root, stem and pod, and the accumulation of GmTIP2;3 transcript showed a significant response to osmotic stresses, including 20% PEG6000 (polyethylene glycol and 100 µM ABA (abscisic acid treatments. The promoter-GUS (glucuronidase activity analysis suggested that GmTIP2;3 was also expressed in the root, stem and leaf and preferentially expressed in the stele of root and stem, and the core promoter region was 1000 bp in length, located upstream of the ATG start codon. The GUS tissue and induced expression observations were consistent with the findings in soybean. In addition, subcellular localization showed that GmTIP2;3 was a plasma membrane-localized protein. Yeast heterologous expression revealed that GmTIP2;3 could improve tolerance to osmotic stress in yeast cells. Integrating these results, GmTIP2;3 might play an important role in response to osmotic stress in plants .

  7. Temperature variation on root surface with three root-end cavity preparation techniques

    Directory of Open Access Journals (Sweden)

    Bodrumlu Emre

    2013-01-01

    Full Text Available Introduction. Thermal changes can occur on the external root surface when root-end cavity preparation is performed, which may damage periodontal ligament cells and alveolar bone. Objective. The purpose of this study was to evaluate the temperature changes during preparation of the root-end cavities at 1 and 3 mm to the sectioned apical root surfaces when either tungsten carbide round bur, diamond round bur or ultrasonic diamond tip was used. Methods. Root-end resection was performed at 90° to the long axis of the root, 3 mm from the apex. Specimens were randomly divided into three groups of 12 teeth each for three different root-end cavity preparation techniques to be used, i.e. tungsten carbide bur, diamond bur and ultrasonic diamond retro tip. Thermocouples were used to measure temperature changes at 1 mm (T1 and 3 mm (T2 to the cutting plane during the preparations. Results. For T1, the lowest and the highest mean temperature increases of 3.53°C and 4.34°C were recorded for the carbide and diamond burs, respectively. For T2, the lowest and the highest mean temperature increases of 2.62°C and 4.39°C where recorded for the carbide and diamond burs, respectively. The mean temperatures with the ultrasonic tip were 3.68 and 3.04 ºC at T1 and T2 region, respectively. For root-end preparation, the ultrasonic preparation technique took the shortest preparation time (10.25 sec and the diamond bur took the longest time (28.17 sec. Conclusion. Ultrasonic retro tips and burs caused temperature to rise from 2.62° to 4.39°C, and these rises were within safety levels.

  8. Root resorption

    DEFF Research Database (Denmark)

    Kjaer, Inger

    2014-01-01

    Introduction: This paper summarizes the different conditions, which have a well-known influence on the resorption of tooth roots, exemplified by trauma and orthodontic treatment. The concept of the paper is to summarize and explain symptoms and signs of importance for avoiding resorption during...... orthodontic treatment. The Hypothesis: The hypothesis in this paper is that three different tissue layers covering the root in the so-called periroot sheet can explain signs and symptoms of importance for avoiding root resorption during orthodontic treatment. These different tissue layers are; outermost...... processes provoked by trauma and orthodontic pressure. Inflammatory reactions are followed by resorptive processes in the periroot sheet and along the root surface. Evaluation of the Hypothesis: Different morphologies in the dentition are signs of abnormal epithelium or an abnormal mesodermal layer. It has...

  9. 硼胁迫对枳橙砧木细根根尖成熟区和幼嫩叶片细胞结构的影响%Effects of Boron Deficiency on Cellular Structures of Maturation Zone from Root Tips and Functional Leaves from Middle and Upper Plant in Trifoliate Orange Rootstock

    Institute of Scientific and Technical Information of China (English)

    刘磊超; 姜存仓; 董肖昌; 吴秀文; 刘桂东; 卢晓佩

    2015-01-01

    胞内淀粉粒积累加剧;影响叶片中海绵组织细胞形态大小,细胞出现不正常增生,从而抑制砧木根尖及叶片中维管束的发育。%[Objective]The aim of this study was to determine the effects of boron deficiency on the cellular structures of the maturation zone in root tips and the functional leaves in citrus.[Method]A hydroponic experiment was conducted with (10μmol·L-1 H3BO3, +B) and without boron (-B) treatment. Fine root mature zone and young leaf samples were observed by paraffin sections and transmission electron microscope (TEM).[Result]Boron deficiency reduced the amount of parenchyma cell in root and, arranged loosely, led to cell deformation and enlarged the intercellular space. Also, boron deficiency caused the disintegration of the cytoplasm and organelles, and increased the cell wall. Whereas the parenchyma cell morphology was normal, evenly sized, and arranged densely in +B treatment, the parafin section showed the root vascular bundle was dyed deeper and the structure was clearly organized in a circular pattern around the root pulp. Low B stress seriously inhibited the development of vascular bundle and restricted its differentiation, making the cell small and randomly arranged. In the plant, Boron leakage made the leaves thick and uneven and sponge tissue became deformed, leading to bigger cell gaps and an increase in the number and volume of sponge tissue. This improved the proportion of sponge tissue in mesophyll. However, in B+ treatment, leaf thickness was more even and the epidermis cell was more densely arranged. The palisade mesophyll was closely packed and sponge tissue underneath was loosely and organically arranged. Under B deficiency, there was also an accumulation of starch grains in the cell and leaf soluble sugar and starch content increased by 35.3% and 66.7%, respectively. But there was no obvious accumulation of starch in the leaves with +B treatment.[Conclusion] The internal structure of the

  10. Role of acetylcholine on plant root-shoot signal transduction

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The role of acetylcholine (ACh) on plant root- shoot communication was investigated using the root-split system of Vicia faba L. In the experiments, slight osmotic stress caused the decrease of ACh content in root tips and the xylem sap transported up per time unit from root tip to the shoot when the water potential of the shoot was kept unchanged. It also caused the decrease of ACh content in the abaxial epidermis. The decrease was highly correlative to the changes of transpiration rate, suggesting that the decrease of ACh content probably functions as a signal to regulate stomatal behavior. The effect of osmotic stress might be mainly through the inhibition of the ACh synthesis in root tip; thus further influences the ACh content in root tip, xylem sap and abaxial epidermis and resulting in the changes of stomatal behavior. These results provide new evidence that plants transduce positive and negative signals among roots and shoots to coordinate stomatal behavior and adapt to variable environments.

  11. 核桃根、茎、叶提取物对蚕豆的遗传毒性分析%Genetic toxicity of active ingredients extracted from roots,stems, and leaves of walnut on Vicia faba

    Institute of Scientific and Technical Information of China (English)

    黄元河; 潘乔丹

    2012-01-01

    [目的]研究核桃根、茎、叶不同提取物的化感作用机制,为开发新型无公害植物源除草剂提供科学依据.[方法]采用蚕豆根生长试验和蚕豆微核试验,测定核桃根、茎、叶不同提取物对蚕豆生长的影响和遗传毒性.[结果]经核桃根、叶正丁醇提取物培养24和48h的蚕豆根生长减慢,当核桃根、叶正丁醇提取物浓度大于0.050 g/mL时,培养72 h的蚕豆根生长停滞.微核试验结果,核桃根、叶正丁醇提取物能抑制蚕豆根尖细胞生长,损伤其遗传物质,导致其有丝分裂指数下降、微核率增高,与对照相比呈显著性差异(P<0.05),且在试验浓度范围内(0.025~0.100 g/mL)表现出显著的浓度效应和时间效应.[结论]核桃根和叶中含有一定遗传毒性的化感物质,能够抑制植物细胞分裂,导致细胞遗传物质损伤,对周围植物产生不可逆的遗传损伤效应.%In order to provide scientific evidences for the development of pollution-free botanical herbicides, this study explored the allelopathic mechanism of different extracts from the roots, stems, and leaves of walnut (Juglans regia L.). [ Method jThe Vicia (aba root growth test and micronucleus test were used to study the effects of the different ingredients derived from the roots, stems, and leaves of walnut on Vicia faba growth and their genetic toxicity. [ResultJThe research results showed that the Vicia faba root grew slowly after being cultured by the n-butanol extracts (0.025, 0.050, 0.100 g/mL) from walnut roots and leaves for 24 and 48 hrs, respectively. When the extracts concentration was greater than 0.050 g/mL, the Vicia faba root, which was cultured for 72 hrs, stopped growing. The micronuclear test indicated that the n-butanol extracts of roots and leaves could inhibit the growth of Vicia faba root tip cells and damage the genetic material, which resulted in the mitotic index of Vicia faba root tips to decrease and micronuclear rate to

  12. Influence of hydroponic culture method on morphology and hydraulic conductivity of roots of honey locust.

    Science.gov (United States)

    Graves, W R

    1992-09-01

    The morphology and hydraulic conductivity of root systems of Gleditsia triacanthos L. var. inermis Willd. (honey locust) grown hydroponically in sand and solution cultures were compared. Total root system length was similar in the two cultures. However, root systems grown in solution had longer primary roots, fewer lateral roots and root hairs, and a greater distance between the tip of the primary root and the junction of the youngest secondary root and the primary root than root systems grown in sand. Hydraulic conductivities of root systems grown hydroponically for 21 or 35 days in sand or solution culture were similar. These findings show that different methods of hydroponic culture can affect root morphology without altering root resistance to water transport.

  13. REDUCTION OF GENOTOXICITY OF A CREOSOTE-CONTAMINATED SOIL AFTER FUNGAL TREATMENT DETERMINED BY THE TRADESCANTIA-MICRONUCLEUS TEST

    Science.gov (United States)

    The fungal degradation of polyaromatic hydrocarbons (PAH) in a contaminated soil from a hazarous waste site was evaluated in a pilot-scale study. As some PAH are known to be mutagens, the Tradescantia-micronucleus test (TRAD-MCN) was selected to evaluate the genotoxicity of the s...

  14. Reference control data obtained from an in vivo comet-micronucleus combination assay using Sprague Dawley rats.

    Science.gov (United States)

    Kasamoto, Sawako; Masumori, Shoji; Tanaka, Jin; Ueda, Maya; Fukumuro, Masahito; Nagai, Miho; Yamate, Jyoji; Hayashi, Makoto

    2017-04-04

    According to the International Conference on Harmonization Guidance on Genotoxicity Testing and Data Interpretation for Pharmaceuticals Intended for Human Use (ICH S2(R1)), a positive response in any in vitro assay necessitates additional in vivo test(s) (other tissue/endpoint) in addition to the erythrocyte micronucleus test when Option 1 of the test battery is selected. When Option 2 of the test battery is selected, a bacterial gene mutation test and two in vivo tests with different tissues/endpoint are required. The in vivo alkaline comet assay is recommended as the second in vivo test because it can detect a broad spectrum of DNA damage in any tissue and can be combined with the erythrocyte micronucleus test. Considering animal welfare, a combination assay is preferable to an individual assay. Thus, we validated the protocol for the in vivo comet-micronucleus combination assay in rats with three daily administrations and determined the dose of the positive control (ethyl methanesulfonate; EMS, 200mg/kg/day). We also collected the negative control (vehicle) and positive control (EMS) data from the comet (liver, stomach, and kidney) and micronucleus (bone marrow) combination assay using male Sprague Dawley (SD) rats. The negative control data were comparable to our historical control data obtained from stand-alone assays. The positive control data showed clear and consistent positive responses in both endpoints.

  15. Dependence of the bystander effect for micronucleus formation on dose of heavy-ion radiation in normal human fibroblasts.

    Science.gov (United States)

    Matsumoto, Yoshitaka; Hamada, Nobuyuki; Aoki-Nakano, Mizuho; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi; Kakizaki, Takehiko; Kobayashi, Yasuhiko; Furusawa, Yoshiya

    2015-09-01

    Ionising radiation-induced bystander effects are well recognised, but its dependence on dose or linear energy transfer (LET) is still a matter of debate. To test this, 49 sites in confluent cultures of AG01522D normal human fibroblasts were targeted with microbeams of carbon (103 keV µm(-1)), neon (375 keV µm(-1)) and argon ions (1260 keV µm(-1)) and evaluated for the bystander-induced formation of micronucleus that is a kind of a chromosome aberration. Targeted exposure to neon and argon ions significantly increased the micronucleus frequency in bystander cells to the similar extent irrespective of the particle numbers per site of 1-6. In contrast, the bystander micronucleus frequency increased with increasing the number of carbon-ion particles in a range between 1 and 3 particles per site and was similar in a range between 3 and 8 particles per site. These results suggest that the bystander effect of heavy ions for micronucleus formation depends on dose. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. X-ray computed tomography uncovers root-root interactions: quantifying spatial relationships between interacting root systems in three dimensions

    Directory of Open Access Journals (Sweden)

    Alexander Martin Paya

    2015-04-01

    Full Text Available Research in the field of plant biology has recently demonstrated that inter- and intra-specific interactions belowground can dramatically alter root growth. Our aim was to answer questions related to the effect of inter- vs. intra-specific interactions on the growth and utilization of undisturbed space by fine roots within three dimensions (3D using micro X-ray computed tomography. To achieve this, Populus tremuloides (quaking aspen and Picea mariana (black spruce seedlings were planted into containers as either solitary individuals, or inter-/intra-specific pairs, allowed to grow for two months, and 3D metrics developed in order to quantify their use of belowground space. In both aspen and spruce, inter-specific root interactions produced a shift in the vertical distribution of the root system volume, and deepened the average position of root tips when compared to intra-specifically growing seedlings. Inter-specific interactions also increased the minimum distance between root tips belonging to the same root system. There was no effect of belowground interactions on the radial distribution of roots, or the directionality of lateral root growth for either species. In conclusion, we found that significant differences were observed more often when comparing controls (solitary individuals and paired seedlings (inter- or intra-specific, than when comparing inter- and intra-specifically growing seedlings. This would indicate that competition between neighboring seedlings was more responsible for shifting fine root growth in both species than was neighbor identity. However, significant inter- vs. intra-specific differences were observed, which further emphasizes the importance of biological interactions in competition studies.

  17. Differences in U root-to-shoot translocation between plant species explained by U distribution in roots

    Energy Technology Data Exchange (ETDEWEB)

    Straczek, Anne; Duquene, Lise [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Wegrzynek, Dariusz [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Krakow (Poland); Chinea-Cano, Ernesto [IAEA, Seibersdorf Laboratories, A-2444 Seibersdorf (Austria); Wannijn, Jean [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium); Navez, Jacques [Royal Museum of Africa, Department of Geology, Leuvensesteenweg 13, 3080 Tervuren (Belgium); Vandenhove, Hildegarde, E-mail: hvandenh@sckcen.b [Belgium Nuclear Research Centre (SCK.CEN), Biosphere Impact Studies, Boeretang 200, 2400 Mol (Belgium)

    2010-03-15

    Accumulation and distribution of uranium in roots and shoots of four plants species differing in their cation exchange capacity of roots (CECR) was investigated. After exposure in hydroponics for seven days to 100 mumol U L{sup -1}, distribution of uranium in roots was investigated through chemical extraction of roots. Higher U concentrations were measured in roots of dicots which showed a higher CECR than monocot species. Chemical extractions indicated that uranium is mostly located in the apoplasm of roots of monocots but that it is predominantly located in the symplasm of roots of dicots. Translocation of U to shoot was not significantly affected by the CECR or distribution of U between symplasm and apoplasm. Distribution of uranium in roots was investigated through chemical extraction of roots for all species. Additionally, longitudinal and radial distribution of U in roots of maize and Indian mustard, respectively showing the lowest and the highest translocation, was studied following X-ray fluorescence (XRF) analysis of specific root sections. Chemical analysis and XRF analysis of roots of maize and Indian mustard clearly indicated a higher longitudinal and radial transport of uranium in roots of Indian mustard than in roots of maize, where uranium mostly accumulated in root tips. These results showed that even if CECR could partly explain U accumulation in roots, other mechanisms like radial and longitudinal transport are implied in the translocation of U to the shoot.

  18. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    silicon processing. Using a microgripper they were detached from an array and fixed to a standard pyramidal AFM probe or alternatively inserted into a tipless cantilever equipped with a narrow slit. The nanobit-enhanced probes were used for imaging of deep trenches, without visible deformation, wear......We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard...... or dislocation of the tips of the nanobit after several scans. This approach allows an unprecedented freedom in adapting the shape and size of scanning probe tips to the surface topology or to the specific application....

  19. Soil genotoxicity assessment--results of an interlaboratory study on the Vicia micronucleus assay in the context of ISO standardization.

    Science.gov (United States)

    Cotelle, Sylvie; Dhyèvre, Adrien; Muller, Serge; Chenon, Pascale; Manier, Nicolas; Pandard, Pascal; Echairi, Abdelwahad; Silvestre, Jérôme; Guiresse, Maritxu; Pinelli, Eric; Giorgetti, Lucia; Barbafieri, Meri; Silva, Valéria C; Engel, Fernanda; Radetski, Claudemir M

    2015-01-01

    The Vicia micronucleus assay was standardized in an international protocol, ISO 29200, "Assessment of genotoxic effects on higher plants-Vicia faba micronucleus test," for soil or soil materials (e.g., compost, sludge, sediment, waste, and fertilizing materials). The aim of this interlaboratory study on the Vicia micronucleus assay was to investigate the robustness of this in vivo assay in terms of its applicability in different countries where each participant were asked to use their own seeds and reference soil, in agreement with the ISO 29200 standard. The ISO 29200 standard protocol was adopted for this study, and seven laboratories from three countries (France, Italy, and Brazil) participated in the study. Negative and positive controls were correctly evaluated by 100 % of the participants. In the solid-phase test, the micronucleus frequency (number of micronuclei/1,000 cells) varied from 0.0 to 1.8 for the negative control (i.e., Hoagland's solution) and from 5.8 to 85.7 for the positive control (i.e., maleic hydrazide), while these values varied from 0.0 to 1.7 for the negative control and from 14.3 to 97.7 for the positive control in the case of liquid-phase test. The variability in the data obtained does not adversely affect the robustness of the protocol assessed, on the condition that the methodology described in the standard ISO 29200 is strictly respected. Thus, the Vicia micronucleus test (ISO 29200) is appropriate for complementing prokaryotic or in vitro tests cited in legislation related to risk assessment of genotoxicity potential.

  20. At the poles across kingdoms: phosphoinositides and polar tip growth.

    Science.gov (United States)

    Ischebeck, Till; Seiler, Stephan; Heilmann, Ingo

    2010-04-01

    Phosphoinositides (PIs) are minor, but essential phospholipid constituents of eukaryotic membranes, and are involved in the regulation of various physiological processes. Recent genetic and cell biological advances indicate that PIs play important roles in the control of polar tip growth in plant cells. In root hairs and pollen tubes, PIs control directional membrane trafficking required for the delivery of cell wall material and membrane area to the growing tip. So far, the exact mechanisms by which PIs control polarity and tip growth are unresolved. However, data gained from the analysis of plant, fungal and animal systems implicate PIs in the control of cytoskeletal dynamics, ion channel activity as well as vesicle trafficking. The present review aims at giving an overview of PI roles in eukaryotic cells with a special focus on functions pertaining to the control of cell polarity. Comparative screening of plant and fungal genomes suggests diversification of the PI system with increasing organismic complexity. The evolutionary conservation of the PI system among eukaryotic cells suggests a role for PIs in tip growing cells in models where PIs so far have not been a focus of attention, such as fungal hyphae.

  1. Office 2010 Visual Quick Tips

    CERN Document Server

    Gunter, Sherry Kinkoph

    2010-01-01

    Get more done in Office 2010 in less time with these Quick Tips!. Whether you're new to Microsoft Office or updating from older versions, this is the perfect resource to get you quickly up to speed on Office 2010. Every application is covered, including Word, Excel, PowerPoint, Outlook, and Publisher. Full-color screenshots and numbered steps clearly explain dozens of features and functions-while quick shortcuts, tips, and tricks help you save time and boost productivity. You'll also find great new ways to access and use some Office apps right from the Web.: Walks you through dozens of new fea

  2. [Technical Tips for Spinal Anesthesia].

    Science.gov (United States)

    Shima, Takeshi

    2015-09-01

    Spinal anesthesia is a standard technique for all anesthesiologists and surgeons. This review deals with basic knowledge and tips for spinal anesthesia in an empirical manner. It is important to understand practical knowledge about specific character of each local anesthetic, spread patterns of the anesthetics in the subarachnoid space and relation between anesthesia level and puncture site. This review also introduces tips for subarachnoid puncture and divided administration method of isobaric local anesthetic solution based on the literature. Anesthesiologists and surgeons have to recognize that it is necessary to take enough time to perform precious and optimal spinal anesthesia.

  3. ZBrush Professional Tips and Techniques

    CERN Document Server

    Gaboury, Paul

    2012-01-01

    Learn to work effectively and creatively with all versions of ZBrush! ZBrush is used by top artists in Hollywood to model and sculpt characters in such films as Avatar, Iron Man, and Pirates of the Caribbean. In addition, this amazing technology is also used in jewelry design, forensic science, aerospace, video games, toy creation, and the medical field. Written by Pixologic's in-house ZBrush expert Paul Gaboury, this full-color, beautifully illustrated guide provides you with the ultimate tips and tricks to maximize your use of all versions of ZBrush. Reveals numerous little-known tips and tr

  4. Tip Studies using CFD and Comparison with Tip Loss Models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver

    2004-01-01

    of the averaged axial induction factor and the normal and tangential loads are compared with those of a standard blade element momentum code using 2D calibrated airfoil data for a wind speed of 9 m s(-1), where the agreement in computed power is good. Further, a comparison with a new tip loss model proposed...

  5. Monitoring of Human Exposure to Radiation With the Binucleated Lymphocyte Micronucleus Assay 

    Institute of Scientific and Technical Information of China (English)

    HEJI-LINANG; JINHAI-YAN; 等

    2000-01-01

    The micronuclei(MN) of peripheral blood lymphocytes from radiation-exposed people were monitroed with the binucleated lymphocyte micronucleus assay(CBMN),MN rates in people with radiation-disease,radiation exposed and a control group were 12.57%,4.20%and 3.26%,respectively.The MN rate of patients with radiation-disease was significantly higher than those of other groups(P0.05),Meanwhile,chromosome aberrations(CA) of 3 groups were determined.The results were similar to those seen while the MN assay,CA rates were 2.06%,0.93%,and 0.69%,respectively,CA rate of the radiation-disease group was significantly higher than that of other groups(P0.05),The study indicates that the CBMN assay is a rapid,sensitive and accurate method which can be used to monitor a large population exposed to radiation.

  6. Micronucleus as biomarkers of cancer risk in anabolic androgenic steroids users.

    Science.gov (United States)

    Souza, L da Cunha Menezes; da Cruz, L A; Cerqueira, E de Moraes Marcílio; Meireles, Jrc

    2017-03-01

    The use of anabolic androgenic steroids (AAS) has grown among practitioners of recreational bodybuilding, with significant contributions of designer steroids, aiming muscle hypertrophy in healthy subjects. The abusive use of AAS in general is associated with adverse effects; one of the most worrisome is cancer development. The aim of this study was to evaluate the effectiveness of the cytokinesis block micronucleus (CBMN) test in human lymphocytes in identifying risk groups for cancer development in users of AAS. Blood was collected from 15 AAS users bodybuilders (G1), 20 non-users bodybuilders (G2) and 20 non-users sedentary (G3). MN analysis was performed on a minimum of 1000 binucleated lymphocytes. The occurrence of MN was significantly higher ( p < 0.05) in individuals of G1 compared to G2 and G3. The results indicate the sensitivity of CBMN in human lymphocytes in the identification of chromosomal damage in consequence of AAS.

  7. Lanthanum nitrate genotoxicity evaluation: Ames test, mouse micronucleus assay, and chromosome aberration test.

    Science.gov (United States)

    Yang, Hui; Zhang, Xiaopeng; Liu, Haibo; Cui, Wenming; Zhang, Qiannan; Li, Yongning; Yu, Zhou; Jia, Xudong

    2016-11-01

    The increasing use of rare-earth elements (REE) and their compounds has led to their accumulation in the environment and has raised concern about their safety. The toxic effects of REE such as lanthanum are largely unknown; genotoxicity studies have been limited and results are controversial. We evaluated the genotoxicity of lanthanum nitrate (La(NO3)3) in several in vitro and in vivo tests, including bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, and chromosome aberration assay. La(NO3)3 was not mutagenic in the Ames test. La(NO3)3 did not increase the frequencies of bone marrow micronuclei or chromosome aberration in the mouse after repeated treatments at oral doses up to 735 (females) and 855mg/kg (males). The compound did not increase the frequency of chromosome aberrations in CHO cells in vitro. These results indicate that lanthanum is not a genotoxic hazard.

  8. The micronucleus test-most widely used in vivo genotoxicity test.

    Science.gov (United States)

    Hayashi, Makoto

    2016-01-01

    Genotoxicity is commonly evaluated during the chemical safety assessment together with other toxicological endpoints. The micronucleus test is always included in many genotoxic test guidelines for long time in many classes of chemicals, e.g., pharmaceutical chemicals, agricultural chemicals, food additives. Although the trend of the safety assessment of chemicals faces to animal welfare and in vitro systems are more welcome than the in vivo systems, the in vivo test systems are paid more attention in the field of genotoxicity because of its weight of evidence. In this review, I will summarize the following points: 1) historical consideration of the test development, 2) characteristics of the test including advantages and limitations, 3) new approaches considering to the animal welfare.

  9. Genotoxic effect of Lythrum salicaria extract determined by the mussel micronucleus test.

    Science.gov (United States)

    Eck-Varanka, Bettina; Kováts, Nóra; Hubai, Katalin; Paulovits, Gábor; Ferincz, Árpád; Horváth, Eszter

    2015-12-01

    A wide range of aquatic plants have been proven to release allelochemicals, of them phenolics and tannin are considered rather widely distributed. Tannins, however, have been demonstrated to have genotoxic capacity. In our study genotoxic potential of Lythrum salicaria L. (Purple Loosestrife, family Lythraceae) was assessed by the mussel micronucleus test, using Unio pictorum. In parallel, total and hydrolysable tannin contents were determined. Results clearly show that the extract had a high hydrolysable tannin content and significant mutagenic effect. As L. salicaria has been long used in traditional medicine for chronic diarrhoea, dysentery, leucorrhoea and blood-spitting, genotoxic potential of the plant should be evaluated not only with regard to potential effects in the aquatic ecosystem, but also assessing its safe use as a medicinal herb.

  10. The 14-day repeated dose liver micronucleus test with methapyrilene hydrochloride using young adult rats.

    Science.gov (United States)

    Inoue, Kenji; Ochi, Akimu; Koda, Akira; Wako, Yumi; Kawasako, Kazufumi; Doi, Takaaki

    2015-03-01

    The repeated dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect genotoxic hepatocarcinogens that can be integrated into a general toxicity study. The assay methods were thoroughly validated by 19 Japanese facilities. Methapyrilene hydrochloride (MP), known to be a non-genotoxic hepatocarcinogen, was examined in the present study. MP was dosed orally at 10, 30 and 100mg/kg/day to 6-week-old male Crl:CD (SD) rats daily for 14 days. Treatment with MP resulted in an increase in micronucleated hepatocytes (MNHEPs) with a dosage of only 100mg/kg/day. At this dose level, cytotoxicity followed by regenerative cell growth was noted in the liver. These findings suggest that MP may induce clastogenic effects indirectly on the liver or hepatotoxicity of MP followed by regeneration may cause increase in spontaneous incidence of MNHEPs.

  11. Effects of dental adhesives on micronucleus frequency in peripheral blood lymphocytes in vitro.

    Science.gov (United States)

    Prica, Dunja; Tadin, Antonija; Marović, Danijela; Katunarić, Marina; Prica, Adriana; Galić, Nada

    2013-09-01

    Dental adhesives come into direct contact with oral tissues. Due to this close and long-term contact, the materials should exhibit a high degree of biocompatibility. The aim of this study was to evaluate the genotoxic effect of dental adhesives on human lymphocytes in vitro. Polymerized dental adhesives (Excite, Adper Single Bond 2, Prompt L-pop and OptiBond Solo Plus) were eluted in dimethyl sulfoxide for 1 hour, 24 h and 120 h (5 days). Thereafter, lymphocyte cultures were treated with different concentrations of eluates (0.2 microg/mL, 0.5 microg/mL and 5 microg/mL) obtained from each of the tested materials. Genotoxicity was evaluated by micronucleus test. The chi2-test was used on statistical analysis (p dental adhesives causes genotoxic effects in human lymphocytes. Toxic effect of these dental adhesives increases with the tested material concentration and decreases with the length of elution period.

  12. Micronucleus test and metaphase analyses in mice exposed to known and suspected spindle poisons.

    Science.gov (United States)

    Marrazzini, A; Betti, C; Bernacchi, F; Barrai, I; Barale, R

    1994-11-01

    Micronucleus (Mn) and metaphase chromosome analyses were performed in mouse bone marrow cells with two known and eight suspected mitotic spindle poisons. Polychromatic (PCEs) and normochromatic (NCEs) erythrocytes were scored for presence of Mn, while structural (CAs) and numerical chromosome aberrations (NCAs), i.e. hyperploid cells, were evaluated by metaphase analysis. CAs were scored in first, and NCAs in the second metaphases, identified by BrdUrd differential staining. Hydroquinone induced Mn, NCAs and CAs; colchicine, vinblastine and, to a lesser extent, chloral hydrate, diazepam and econazole induced both Mn and NCAs; cadmium chloride and thimerosal induced Mn and CAs, while pyrimethamine and thiabendazole induced Mn only. The proposed stepwise protocol allowed satisfactory statistical evaluation of the effects induced with a reduction in the number of animals killed. An acceptable agreement was found between induction of Mn and NCAs, suggesting a possible use of the Mn test for revealing compounds with aneugenic properties.

  13. Structural and numerical chromosome aberration inducers in liver micronucleus test in rats with partial hepatectomy.

    Science.gov (United States)

    Itoh, Satoru; Hattori, Chiharu; Nagata, Mayumi; Sanbuissho, Atsushi

    2012-08-30

    The liver micronucleus test is an important method to detect pro-mutagens such as active metabolites not reaching bone marrow due to their short lifespan. We have already reported that dosing of the test compound after partial hepatectomy (PH) is essential to detect genotoxicity of numerical chromosome aberration inducers in mice [Mutat. Res. 632 (2007) 89-98]. In naive animals, the proportion of binucleated cells in rats is less than half of that in mice, which suggests a species difference in the response to chromosome aberration inducers. In the present study, we investigated the responses to structural and numerical chromosome aberration inducers in the rat liver micronucleus test. Two structural chromosome aberretion inducers (diethylnitrosamine and 1,2-dimethylhydrazine) and two numerical chromosome aberration inducers (colchicine and carbendazim) were used in the present study. PH was performed a day before or after the dosing of the test compound in 8-week old male F344 rats and hepatocytes were isolated 4 days after the PH. As a result, diethylnitrosamine and 1,2-dimethylhydrazine, structural chromosome aberration inducers, exhibited significant increase in the incidence of micronucleated hepatocyte (MNH) when given either before and after PH. Colchicine and carbendazim, numerical chromosome aberration inducers, did not result in any toxicologically significant increase in MNH frequency when given before PH, while they exhibited MNH induction when given after PH. It is confirmed that dosing after PH is essential in order to detect genotoxicity of numerical chromosome aberration inducers in rats as well as in mice. Regarding the species difference, a different temporal response to colchicine was identified. Colchicine increased the incidence of MNH 4 days after PH in rats, although such induction in mice was observed 8-10 days after PH.

  14. Shoot Tip Culture of Arnica montana for Micropropagation.

    Science.gov (United States)

    Conchou, O; Nichterlein, K; Vömel, A

    1992-02-01

    Multiple shoots were regenerated from shoot tips of ARNICA MONTANA on MS and B5 media supplemented with BA (1 mg/l) and NAA (0.1 mg/l). Sections of 1-2 mm in length cultured from IN VITRO germinated seedlings regenerated 7.7 (mean) shoots on the MS medium, whereas sections cultured from greenhouse plants regenerated 9.0 (mean) shoots on the B5 medium within 6 weeks. Subsequent subcultures of shoots on the same media but without NAA resulted in similar or lower multiplication rates (1.6 to 3.1 in 3 weeks). Shoot development was promoted, whereas shoot initiation was simultaneously inhibited by the addition of activated charcoal to the media. Rooting was induced by culturing shoots from seedling as well as from greenhouse plant shoot tips on MS or B5 medium supplemented with NAA. The plantlets were transplanted into soil and grown successfully under greenhouse and field conditions.

  15. Root border cells and secretions as critical elements in plant host defense.

    Science.gov (United States)

    Driouich, Azeddine; Follet-Gueye, Marie-Laure; Vicré-Gibouin, Maïté; Hawes, Martha

    2013-08-01

    Border cells and border-like cells are released from the root tip as individual cells and small aggregates, or as a group of attached cells. These are viable components of the root system that play a key role in controlling root interaction with living microbes of the rhizosphere. As their separation from root tip proceeds, the cells synthesize and secrete a hydrated mucilage that contains polysaccharides, secondary metabolites, antimicrobial proteins and extracellular DNA (exDNA). This exDNA-based matrix seems to function in root defense in a way similar to that of recently characterized neutrophil extracellular traps (NETs) in mammalian cells. This review discusses the role of the cells and secreted compounds in the protection of root tip against microbial infections.

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the equipment look like? How does the procedure work? How is the procedure performed? What will I experience during and after the procedure? Who interprets the results and how do I get them? What are the benefits vs. risks? What are the limitations of TIPS? ...

  17. Top 10 Staff Survival Tips.

    Science.gov (United States)

    O'Brien, Laurie

    1995-01-01

    Tips for camp staff on how to survive summer camp include not giving campers sugary drinks before bedtime, setting behavior limits with campers, setting an example by following camp rules, getting enough rest, being fair and consistent, controlling anger, being accountable for actions, asking questions, and being flexible. (LP)

  18. Sports Injury Prevention Tip Sheet

    Science.gov (United States)

    ... Commemorative Giving Employment at AAP Advertise with AAP Advertising on AAP.org Advertising on AAP Journals & Publications AAP Mailing and eMail ... Help/Feedback a a a print email share Facebook Twitter 2017 Sports Injury Prevention Tip Sheet 3/ ...

  19. Assigning Effective Homework. Classroom Tips

    Science.gov (United States)

    American Federation of Teachers (NJ), 2010

    2010-01-01

    Each new school year brings high hopes, great expectations and challenges for both new and seasoned educators. The American Federation of Teachers (AFT) has developed a series called "Classroom Tips" to help educators start the year right and anticipate the year ahead. Over the past 40 years, most research studies on homework have found that…

  20. 99 Tips for Safe Schools.

    Science.gov (United States)

    Kaufer, Steve

    This pamphlet highlights 99 tips for maintaining safe schools. Areas of interest include: alarm systems and control of access, vandalism, parent education, transportation, school design, personnel training, and graffiti. The majority of the pointers deal with maintaining and implementing various forms of electronic surveillance and strategies for…

  1. Library Management Tips that Work

    Science.gov (United States)

    Smallwood, Carol, Ed.

    2011-01-01

    There's no shortage of library management books out there--but how many of them actually tackle the little details of day-to-day management, the hard-to-categorize things that slip through the cracks of a larger handbook? "Library Management Tips that Work" does exactly that, addressing dozens of such issues facing library managers, including: (1)…

  2. Library Management Tips that Work

    Science.gov (United States)

    Smallwood, Carol, Ed.

    2011-01-01

    There's no shortage of library management books out there--but how many of them actually tackle the little details of day-to-day management, the hard-to-categorize things that slip through the cracks of a larger handbook? "Library Management Tips that Work" does exactly that, addressing dozens of such issues facing library managers, including: (1)…

  3. Blade tip timing (BTT) uncertainties

    Science.gov (United States)

    Russhard, Pete

    2016-06-01

    Blade Tip Timing (BTT) is an alternative technique for characterising blade vibration in which non-contact timing probes (e.g. capacitance or optical probes), typically mounted on the engine casing (figure 1), and are used to measure the time at which a blade passes each probe. This time is compared with the time at which the blade would have passed the probe if it had been undergoing no vibration. For a number of years the aerospace industry has been sponsoring research into Blade Tip Timing technologies that have been developed as tools to obtain rotor blade tip deflections. These have been successful in demonstrating the potential of the technology, but rarely produced quantitative data, along with a demonstration of a traceable value for measurement uncertainty. BTT technologies have been developed under a cloak of secrecy by the gas turbine OEM's due to the competitive advantages it offered if it could be shown to work. BTT measurements are sensitive to many variables and there is a need to quantify the measurement uncertainty of the complete technology and to define a set of guidelines as to how BTT should be applied to different vehicles. The data shown in figure 2 was developed from US government sponsored program that bought together four different tip timing system and a gas turbine engine test. Comparisons showed that they were just capable of obtaining measurement within a +/-25% uncertainty band when compared to strain gauges even when using the same input data sets.

  4. Sleep Tips for Sjogren's Patients

    Science.gov (United States)

    ... adequate sleep is especially important for those with Sjögren’s syndrome, saying that sleep deprivation exacerbates daytime fatigue and ... tips for better sleep. For more information on Sjögren’s syndrome, visit the SSF Web site at www.sjogrens. ...

  5. Tips voor een goede afstudeerscriptie

    NARCIS (Netherlands)

    Dubbeling, D.J.

    2014-01-01

    'Streng zijn voor jezelf' is het credo om met een goede HBO-afstudeerscriptie voor de dag te komen, want voor je het weet beoordelen meer partijen dan je lief is jouw werk. Hoe doe je dat? Een paar tips naar aanleiding van een kleine inventarisatie van scripties van de post-HBO-opleiding Kostendesku

  6. Isolated root caps, border cells, and mucilage from host roots stimulate hyphal branching of the arbuscular mycorrhizal fungus, Gigaspora gigantea.

    Science.gov (United States)

    Nagahashi, Gerald; Douds, David D

    2004-09-01

    Unlike previous reports that have shown that water soluble and volatile compounds from roots or root exudates play an important role in precolonization events during arbuscular mycorrhizal (AM) fungus-host root interactions (Bécard & Piché 1989, Giovannetti et al. 1993), the results shown here deal with particulate and viscous fractions isolated from host roots. Root caps and a slow sedimenting particulate fraction (SSPF) were rapidly isolated and separated from Ri T-DNA transformed carrot roots (D. carota) grown in liquid culture. In addition, border cells (BC) and mucilage were isolated from aseptically grown corn seedlings (Zea mays). Root caps, SSPF (composed mainly of small root cap fragments and some BCs), BCs, and mucilage all had an associated AM fungus hyphal branching stimulator. Root caps stored for 5 d at 4 degrees C appeared to either synthesize or slowly release the branching stimulator. Also, isolated root caps from roots grown in the absence of P contained more branch stimulating activity than those isolated from roots grown in the presence of P. Although the branching stimulation activity in particulate fractions was low compared to that of the exudate, the particulate fractions can stick to the root surface at considerable distances from the root tip. This may be significant during the infection and colonization of host roots at sites far removed from the primary location of exudation.

  7. Predicting casualties implied by TIPs

    Science.gov (United States)

    Trendafiloski, G.; Wyss, M.; Wyss, B. M.

    2009-12-01

    When an earthquake is predicted, forecast, or expected with a higher than normal probability, losses are implied. We estimated the casualties (fatalities plus injured) that should be expected if earthquakes in TIPs (locations of Temporarily Increased Probability of earthquakes) defined by Kossobokov et al. (2009) should occur. We classified the predictions of losses into the categories red (more than 400 fatalities or more than 1,000 injured), yellow (between 100 and 400 fatalities), green (fewer than 100 fatalities), and gray (undetermined). TIPs in Central Chile, the Philippines, Papua, and Taiwan are in the red class, TIPs in Southern Sumatra, Nicaragua, Vanatu, and Honshu in the yellow class, and TIPs in Tonga, Loyalty Islands, Vanatu, S. Sandwich Islands, Banda Sea, and the Kuriles, are classified as green. TIPs where the losses depend moderately on the assumed point of major energy release were classified as yellow; TIPs such as in the Talaud Islands and in Tonga, where the losses depend very strongly on the location of the epicenter, were classified as gray. The accuracy of loss estimates after earthquakes with known hypocenter and magnitude are affected by uncertainties in transmission and soil properties, the composition of the building stock, the population present, and the method by which the numbers of casualties are calculated. In the case of TIPs, uncertainties in magnitude and location are added, thus we calculate losses for a range of these two parameters. Therefore, our calculations can only be considered order of magnitude estimates. Nevertheless, our predictions can come to within a factor of two of the observed numbers, as in the case of the M7.6 earthquake of October 2005 in Pakistan that resulted in 85,000 fatalities (Wyss, 2005). In subduction zones, the geometrical relationship between the earthquake source capable of a great earthquake and the population is clear because there is only one major fault plane available, thus the epicentral

  8. Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study

    Directory of Open Access Journals (Sweden)

    Wilson Takashi Hida

    2015-02-01

    Full Text Available Purpose: To compare the efficiency of surgical procedures using three phaco tip designs in torsional phacoemulsification using the bevel-down technique. Methods: In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini-flared 30-degree Kelman tip, or Sidewinder 30-degree Kelman tip. Clinical measurements included preoperative and 3-month postoperative corrected distance visual acuity (CDVA, endothelial cell counts (ECC, and preoperative and 1-day postoperative central corneal thickness (CCT. Intraoperative measurements included phaco time, torsional time, aspiration time, case time, cumulative dissipated energy (CDE, and balanced salt solution volume (BSS. Results: The study evaluated 150 eyes of 150 patients. Intraoperatively, there was no statistically significant difference in cumulative dissipated energy, case time, torsional time, and aspiration time between the three tip configurations. However, less phaco time was used with the mini-flared 45-degree Kelman tip (p=0.02 than that with the Sidewinder 30-degree Kelman tip or reversed mini-flared 30-degree Kelman tip. The mini-flared 45-degree Kelman tip and the reversed mini-flared 30-degree Kelman tip required significantly less balanced salt solution volume than that required by the Sidewinder 30-degree Kelman tip (p=0.009. There was no statistically significant difference in corrected distance visual acuity and endothelial cell counts between tips 3 months postoperatively (p>0.05. Conclusion: All three tips were effective with no intraoperative complications. When using torsional phacoemulsification through microincisions and the prefracture technique with the bevel-down technique, the mini-flared 45-degree Kelman tip required a lower mean phaco time than the reversed mini-flared 30-degree Kelman tip and the Sidewinder 30-degree Kelman tip.

  9. Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study.

    Science.gov (United States)

    Hida, Wilson Takashi; Tzelikis, Patrick Frensel; Nakano, Celso Takashi; Motta, Antonio Francisco Pimenta; Alves, Milton Ruiz

    2015-01-01

    To compare the efficiency of surgical procedures using three phaco tip designs in torsional phacoemulsification using the bevel-down technique. In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini-flared 30-degree Kelman tip, or Sidewinder 30-degree Kelman tip. Clinical measurements included preoperative and 3-month postoperative corrected distance visual acuity (CDVA), endothelial cell counts (ECC), and preoperative and 1-day postoperative central corneal thickness (CCT). Intraoperative measurements included phaco time, torsional time, aspiration time, case time, cumulative dissipated energy (CDE), and balanced salt solution volume (BSS). The study evaluated 150 eyes of 150 patients. Intraoperatively, there was no statistically significant difference in cumulative dissipated energy, case time, torsional time, and aspiration time between the three tip configurations. However, less phaco time was used with the mini-flared 45-degree Kelman tip (p=0.02) than that with the Sidewinder 30-degree Kelman tip or reversed mini-flared 30-degree Kelman tip. The mini-flared 45-degree Kelman tip and the reversed mini-flared 30-degree Kelman tip required significantly less balanced salt solution volume than that required by the Sidewinder 30-degree Kelman tip (p=0.009). There was no statistically significant difference in corrected distance visual acuity and endothelial cell counts between tips 3 months postoperatively (p>0.05). All three tips were effective with no intraoperative complications. When using torsional phacoemulsification through microincisions and the prefracture technique with the bevel-down technique, the mini-flared 45-degree Kelman tip required a lower mean phaco time than the reversed mini-flared 30-degree Kelman tip and the Sidewinder 30-degree Kelman tip.

  10. Evaluation of apical preparations performed with ultrasonic diamond and stainless steel tips at different intensities using a scanning electron microscope in endodontic surgery.

    Science.gov (United States)

    Rodríguez-Martos, Ramón; Torres-Lagares, Daniel; Castellanos-Cosano, Lizett; Serrera-Figallo, María-Angeles; Segura-Egea, Juan-José; Gutierrez-Perez, Jose-Luis

    2012-11-01

    The objective of our study is to analyse (with the help of scanning electron microscopes) the quality of the dental root surface and the appearance of dental cracks after performing apical preparations using two different types of ultrasonic tips. We used 32 single-rooted teeth that underwent a root canal and apical resection. Afterwards, the teeth were divided into 4 groups of 8 teeth each, with preparations of the apical cavities in the following manner: Group 1: stainless steel ultrasonic tip at 33 KHz. Group 2: stainless steel ultrasonic tip at 30 KHz. Group 3: diamond ultrasonic tip at 30 KHz. Group 4: diamond ultrasonic tip at 33 KHz. The quality of the root surface and the presence of cracks were evaluated by one single observer using a scanning electron microscope. All of the teeth in our study had cracks after the apical preparations. The mean number of cracks per tooth ranged between 6. ± 1.9 (group 1) and 3.5 ± 2.4 (group 4), with a significantly higher number found in the groups that used stainless steel tips (P=.03). The types of cracks produced involved: 8 complete cracks (4.5%), 167 incomplete cracks (94.4%), and 2 intradentinal cracks (1.1%), with no significant differences observed between the different frequencies used for each group. Stainless steel ultrasonic tips provoked a larger number of cracks than diamond tips. The frequency of vibration used did not have any effect on the number of cracks found.

  11. The Stability of Tip Vortices Generated by a Flexible Wind Turbine

    Science.gov (United States)

    Rodriguez', Steven; Jaworski, Justin

    2016-11-01

    The influence of root-vortices and a trailing vortex sheet on tip-vortex dynamics of a flexible onshore and floating-offshore wind turbine configurations are investigated numerically. The rotor near-wake is generated using a lifting-line free vortex wake method, which is coupled to a finite element solver for linear flapwise bending deformations. A synthetic time series of rigid-body rotor motions emulates the offshore environment for the NREL 5MW reference wind turbine. To evaluate the influence of root vortices and the trailing vortex sheet, a linear stability analysis is first performed for a rotor wake consisting only of the tip vortices. The stability analysis is then modified to account for the presence of the root vortices and trailing vortex sheet. Stability trends of the two analyses are compared to identify any influence that the root vortices and the trailing vortex sheet have on the tip-vortex dynamics. Lastly, the aforementioned stability analyses are conducted for varying tip speed ratios to identify intrinsically stable helical structures.

  12. Tips for Good Oral Health during Pregnancy

    Science.gov (United States)

    Tips for Good Oral Health During Pregnancy B elow are tips for taking care of your oral health while you are pregnant. Getting oral health care, practicing good oral hygiene, eating healthy foods, ...

  13. Tissue-Specific Localization of Pea Root Infection by Nectria haematococca. Mechanisms and Consequences

    National Research Council Canada - National Science Library

    Uvini Gunawardena; Marianela Rodriguez; David Straney; John T. Romeo; Hans D. VanEtten; Martha C. Hawes

    2005-01-01

    .... The failure to infect the root tip was not due to a failure to induce spore germination at this site, suppression of pathogenicity genes in the fungus, or increased expression of plant defense genes...

  14. Endocardial tip cells in the human embryo - facts and hypotheses.

    Directory of Open Access Journals (Sweden)

    Mugurel C Rusu

    Full Text Available Experimental studies regarding coronary embryogenesis suggest that the endocardium is a source of endothelial cells for the myocardial networks. As this was not previously documented in human embryos, we aimed to study whether or not endothelial tip cells could be correlated with endocardial-dependent mechanisms of sprouting angiogenesis. Six human embryos (43-56 days were obtained and processed in accordance with ethical regulations; immunohistochemistry was performed for CD105 (endoglin, CD31, CD34, α-smooth muscle actin, desmin and vimentin antibodies. Primitive main vessels were found deriving from both the sinus venosus and aorta, and were sought to be the primordia of the venous and arterial ends of cardiac microcirculation. Subepicardial vessels were found branching into the outer ventricular myocardium, with a pattern of recruiting α-SMA+/desmin+ vascular smooth muscle cells and pericytes. Endothelial sprouts were guided by CD31+/CD34+/CD105+/vimentin+ endothelial tip cells. Within the inner myocardium, we found endothelial networks rooted from endocardium, guided by filopodia-projecting CD31+/CD34+/CD105+/ vimentin+ endocardial tip cells. The myocardial microcirculatory bed in the atria was mostly originated from endocardium, as well. Nevertheless, endocardial tip cells were also found in cardiac cushions, but they were not related to cushion endothelial networks. A general anatomical pattern of cardiac microvascular embryogenesis was thus hypothesized; the arterial and venous ends being linked, respectively, to the aorta and sinus venosus. Further elongation of the vessels may be related to the epicardium and subepicardial stroma and the intramyocardial network, depending on either endothelial and endocardial filopodia-guided tip cells in ventricles, or mostly on endocardium, in atria.

  15. 体外微核试验重要影响因素研究%Study on Major Factors Influencing in Vitro Micronucleus Test

    Institute of Scientific and Technical Information of China (English)

    管莹; 高茜; 朱洲海; 米其利; 李雪梅; 缪明明; 夭建华

    2013-01-01

    为了提高体外微核试验结果的可重复性和可比性,通过依据不同判定标准对同一受试物诱发细胞微核率进行统计、检测同一受试物对不同代次CHO细胞的微核率,研究了判定标准、细胞连续传代代次对体外微核试验结果的影响.结果表明,判定标准的不同对同一受试物诱发细胞微核率有显著影响;随细胞连续传代代次的升高,同一受试物对CHO细胞微核率呈上升趋势,连续传代9代以内细胞微核率较为稳定.判定标准、细胞连续传代代次是体外微核试验需要控制的重要因素.%In order to improve the repeatability and comparability of in vitro micronucleus test,the effects of scoring criteria and cell passage on micronucleus test had been explored by counting the micronucleus rate of CHO cells induced by the same test matter according to different scoring criteria,and testing the micronucleus rate of different passages CHO cells evoked by the same test matter. The results showed that scoring criterion had siginificant effect on the micronucleus rate and the micronucleus rate induced by the same test matter increased with cell passage. The micronucleus rate was reliable within passage of 9. Scoring criterion and cell passage were the important factors for quality control of in vitro micronucleus test.

  16. The Root Cap Determines Ethylene-Dependent Growth and Development in Maize Roots

    Institute of Scientific and Technical Information of China (English)

    Achim Hahn; Roman Zimmermann; Dierk Wanke; Klaus Harter; Hans G.Edelmann

    2008-01-01

    Besides providing protection against mechanical damage to the root tip,the root cap is involved in the perception and processing of diverse external and internal stimuli resulting in altered growth and development.The transduction of these stimuli includes hormonal signaling pathways such as those of auxin,ethylene and cytokinin.Here,we show that the root cap is essential for the ethylene-induced regulation of elongation growth and root hair formation in maize.Exogenously applied ethylene is no longer able to inhibit elongation growth when the root cap has been surgically removed prior to hormone treatment.Reconstitution of the cap positively correlates with the developing capacity of the roots to respond to ethylene again.In contrast,the removal of the root cap does not per se affect growth inhibition controlled by auxin and cytokinin.Furthermore,our semi-quantitative RT-PCR results support earlier findings that the maize root cap is a site of high gene expression activity with respect to sensing and responding to hormones such as ethylene.From these data,we propose a novel function of the root cap which is the establishment of competence to respond to ethylene in the distal zones of the root.

  17. 29 CFR 516.28 - Tipped employees.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Tipped employees. 516.28 Section 516.28 Labor Regulations... EMPLOYERS Records Pertaining to Employees Subject to Miscellaneous Exemptions Under the Act; Other Special Requirements § 516.28 Tipped employees. (a) With respect to each tipped employee whose wages are...

  18. Genotoxic effects of sodium nitrate in onion roots

    OpenAIRE

    Maria-Mihaela ANTOFIE; Doroftei, Elena

    2013-01-01

    The scope of this paper is to assess cyto- and genotoxic effects of sodium nitrate on Allium cepa root tips by using different concentrations (i.e. 0,1%; 1% and 5%) for treating uniform healthy onion bulbs for three different periods of time: 6, 24 and 72 hours. In the end of the experiment the harvested root tips were prepared according to Feulgen’s squash technique using Schiff reagent and the investigations were realized according to Allium test. The cytotoxic and genotoxic effects of nitr...

  19. Lead-induced DNA damage in Vicia faba root cells: potential involvement of oxidative stress.

    Science.gov (United States)

    Pourrut, Bertrand; Jean, Séverine; Silvestre, Jérôme; Pinelli, Eric

    2011-12-24

    Genotoxic effects of lead (0-20μM) were investigated in whole-plant roots of Vicia faba L., grown hydroponically under controlled conditions. Lead-induced DNA damage in V. faba roots was evaluated by use of the comet assay, which allowed the detection of DNA strand-breakage and with the V. faba micronucleus test, which revealed chromosome aberrations. The results clearly indicate that lead induced DNA fragmentation in a dose-dependant manner with a maximum effect at 10μM. In addition, at this concentration, DNA damage time-dependently increased until 12h. Then, a decrease in DNA damages was recorded. The significant induction of micronucleus formation also reinforced the genotoxic character of this metal. Direct interaction of lead with DNA was also evaluated with the a-cellular comet assay. The data showed that DNA breakages were not associated with a direct effect of lead on DNA. In order to investigate the relationship between lead genotoxicity and oxidative stress, V. faba were exposed to lead in the presence or absence of the antioxidant Vitamin E, or the NADPH-oxidase inhibitor dephenylene iodonium (DPI). The total inhibition of the genotoxic effects of lead (DNA breakage and micronucleus formation) by these compounds reveals the major role of reactive oxygen species (ROS) in the genotoxicity of lead. These results highlight, for the first time in vivo and in whole-plant roots, the relationship between ROS, DNA strand-breaks and chromosome aberrations induced by lead. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. DNA damaging effects of carbofuran and its main metabolites on mice by micronucleus test and single cell gel electrophoresis

    Institute of Scientific and Technical Information of China (English)

    ZHOU Pei; LIU Baofeng; LU Yitong

    2005-01-01

    The DNA damaging effects of the carbamate pesticide carbofuran and its four metabolites (carbofuranphenol, 3-ketocarbofuran, 3-hydrocarbofuran and nitrosocarbofuran) on mice were evaluated by single cell gel electrophoresis (SCGE) assay and micronucleus test. KM mice were exposed to test compounds with different doses of 0.1, 0.2 and 0.4mg/kg through intraperitoneal injection two times with an internal of 24 h, and then killed by cervical dislocation 6 h after the second injection. In SCGE assay, isolated mice peripheral blood lymphocytes were employed to determine DNA damaging degree after a 1 h treatment by test compounds and a following electrophoresis. Carbofuran and carbofuranphenol showed negative results in both test and had no obvious toxicity. 3-hydrocarbofuran and nitrosocarbofuran were positive.3-ketocarbofuran could not induce micronucleus formation but caused significant DNA migration in SCGE test. These tests revealed that 3-ketocarbofuran, 3-hydrocarbofuran and nitrosocarbofuran are potential mutagesis and further research is needed.

  1. Alginate-encapsulation of shoot tips of jojoba [Simmondsia chinensis (Link) Schneider] for germplasm exchange and distribution.

    Science.gov (United States)

    Kumar, Sunil; Rai, Manoj K; Singh, Narender; Mangal, Manisha

    2010-12-01

    Shoot tips excised from in vitro proliferated shoots derived from nodal explants of jojoba [Simmondsia chinensis (Link) Schneider] were encapsulated in calcium alginate beads for germplasm exchange and distribution. A gelling matrix of 3 % sodium alginate and 100 mM calcium chloride was found most suitable for formation of ideal calcium alginate beads. Best response for shoot sprouting from encapsulated shoot tips was recorded on 0.8 % agar-solidified full-strength MS medium. Rooting was induced upon transfer of sprouted shoots to 0.8 % agar-solidified MS medium containing 1 mg l(-1) IBA. About 70 % of encapsulated shoot tips were rooted and converted into plantlets. Plants regenerated from encapsulated shoot tips were acclimatized successfully. The present encapsulation approach could also be applied as an alternative method of propagation of desirable elite genotype of jojoba.

  2. Inducing gravitropic curvature of primary roots of Zea mays cv Ageotropic

    Science.gov (United States)

    Moore, R.; Evans, M. L.; Fondren, W. M.

    1990-01-01

    Primary roots of the mutant 'Ageotropic' cultivar of Zea mays are nonresponsive to gravity. Their root caps secrete little or no mucilage and touch the root only at the extreme apex. A gap separates the cap and root at the periphery of the cap. Applying mucilage from normal roots or substances with a consistency similar to that of mucilage to tips of mutant roots causes these roots to become strongly graviresponsive. Gravicurvature stops when these substances are removed. Caps of some mutants secrete small amounts of mucilage and are graviresponsive. These results indicate that (a) the lack of graviresponsiveness in the mutant results from disrupting the transport pathway between the cap and root, (b) movement of the growth-modifying signal from the cap to the root occurs via an apoplastic pathway, and (c) mucilage is necessary for normal communication between the root cap and root in Zea mays cv Ageotropic.

  3. Dose estimation using dicentric chromosome assay and cytokinesis block micronucleus assay: comparison between manual and automated scoring in triage mode.

    Science.gov (United States)

    De Amicis, Andrea; De Sanctis, Stefania; Di Cristofaro, Sara; Franchini, Valeria; Regalbuto, Elisa; Mammana, Giacomo; Lista, Florigio

    2014-06-01

    In cases of an accidental overexposure to ionizing radiation, it is essential to estimate the individual absorbed dose of a potentially radiation-exposed person. For this purpose, biological dosimetry can be performed to confirm, complement or even replace physical dosimetry when this proves to be unavailable. The most validated biodosimetry techniques for dose estimation are the dicentric chromosome assay, the "gold standard" for individual dose assessment, and cytokinesis-block micronucleus assay. However, both assays are time consuming and require skilled scorers. In case of large-scale accidents, different strategies have been developed to increase the throughput of cytogenetic service laboratories. These are the decrease of cell numbers to be scored for triage dosimetry; the automation of procedures including the scoring of, for example, aberrant chromosomes and micronuclei; and the establishment of laboratory networks in order to enable mutual assistance if necessary. In this study, the authors compared the accuracy of triage mode biodosimetry by dicentric chromosome analysis and the cytokinesis block micronucleus assay performing both the manual and the automated scoring mode. For dose estimation using dicentric chromosome assay of 10 blind samples irradiated up to 6.4 Gy of x-rays, a number of metaphase spreads were analyzed ranging from 20 up to 50 cells for the manual and from 20 up to 500 cells for the automatic scoring mode. For dose estimation based on the cytokinesis block micronucleus assay, the micronucleus frequency in both 100 and 200 binucleated cells was determined by manual and automatic scoring. The results of both assays and scoring modes were compared and analyzed considering the sensitivity, specificity, and accuracy of dose estimation with regard to the discrimination power of clinically relevant binary categories of exposure doses.

  4. 21. New developments in the lymphocyte micronucleus assay-the effect of diet, genotype and the importance of nucleoplasmic bridges

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The cytokinesis-block micronucleus(CBMN)assay is an established method for studying chromosome breakage and loss in human cells both in vitro and in vivo. However, its use in the study of genomic stability could be improved by a better understanding of the impact of (a) micronutrients (b) genetic background and (c) of other associated important nuclear events indicative of chromosome rearrangement (ie nucleoplasmic

  5. Bacterial Traits Involved in Colonization of Arabidopsis thaliana Roots by Bacillus amyloliquefaciens FZB42.

    Science.gov (United States)

    Dietel, Kristin; Beator, Barbara; Budiharjo, Anto; Fan, Ben; Borriss, Rainer

    2013-03-01

    Colonization studies previously performed with a green-fluorescent-protein, GFP, labeled derivative of Bacillus amyloliquefaciens FZB42 revealed that the bacterium behaved different in colonizing surfaces of plant roots of different species (Fan et al., 2012). In order to extend these studies and to elucidate which genes are crucial for root colonization, we applied targeted mutant strains to Arabidopsis seedlings. The fates of root colonization in mutant strains impaired in synthesis of alternative sigma factors, non-ribosomal synthesis of lipopeptides and polyketides, biofilm formation, swarming motility, and plant growth promoting activity were analyzed by confocal laser scanning microscopy. Whilst the wild-type strain heavily colonized surfaces of root tips and lateral roots, the mutant strains were impaired in their ability to colonize root tips and most of them were unable to colonize lateral roots. Ability to colonize plant roots is not only dependent on the ability to form biofilms or swarming motility. Six mutants, deficient in abrB-, sigH-, sigD-, nrfA-, yusV and RBAM017410, but not affected in biofilm formation, displayed significantly reduced root colonization. The nrfA- and yusV-mutant strains colonized border cells and, partly, root surfaces but did not colonize root tips or lateral roots.

  6. Alternating tip splitting in directional solidification.

    Science.gov (United States)

    Utter, B; Ragnarsson, R; Bodenschatz, E

    2001-05-14

    We report experimental results on the tip splitting dynamics of seaweed growth in directional solidification of succinonitrile alloys. Despite the random appearance of the growth, a tip splitting morphology was observed in which the tip alternately splits to the left and to the right. The tip splitting frequency f was found to be related to the growth velocity V as a power law f~V1.5. This finding is consistent with the predictions of a tip splitting model that is also presented. Small anisotropies are shown to lead to different kinds of seaweed morphologies.

  7. Why Does the Treasury Issue TIPS? The TIPS-Treasury Bond Puzzle

    OpenAIRE

    Hanno Lustig

    2011-01-01

    We show that the price of a Treasury bond and an inflation-swapped TIPS issue exactly replicating the cash flows of the Treasury bond can differ by more than $20 per $100 notional. Treasury bonds are almost always overvalued relative to TIPS. Total TIPS-Treasury mispricing has exceeded $56 billion, representing nearly eight percent of the total amount of TIPS outstanding. TIPS-Treasury mispricing is strongly related to supply factors such as Treasury debt issuance and the availability of coll...

  8. My favorite tips from the "clinical interviewing tip of the month" archive.

    Science.gov (United States)

    Shea, Shawn Christopher

    2007-06-01

    The "Interviewing Tips of the Month" on the Website of the Training Institute for Suicide Assessment and Clinical Interviewing are supplied by visitors to the Website or by participants in the author's workshops. Each month the author chooses a favorite tip for posting and then adds the past month's tip to the "Tip Archive." This article describes eight effective tips for uncovering sensitive material such as antisocial behavior, substance abuse, and physical violence as well as a technique for improving medication adherence.

  9. Clinical application of micronucleus test: a case-control study on the prediction of breast cancer risk/susceptibility.

    Science.gov (United States)

    Bolognesi, Claudia; Bruzzi, Paolo; Gismondi, Viviana; Volpi, Samantha; Viassolo, Valeria; Pedemonte, Simona; Varesco, Liliana

    2014-01-01

    The micronucleus test is a well-established DNA damage assay in human monitoring. The test was proposed as a promising marker of cancer risk/susceptibility mainly on the basis of studies on breast cancer. Our recent meta-analysis showed that the association between micronuclei frequency, either at baseline or after irradiation, and breast cancer risk or susceptibility, has been evaluated in few studies of small size, with inconsistent results. The aim of the present study is to investigate the role of micronucleus assay in evaluating individual breast cancer susceptibility. Two-hundred and twenty untreated breast cancer patients and 295 female controls were enrolled in the study. All women were characterized for cancer family history and 155 subjects were evaluated for the presence of BRCA mutations. Micronuclei frequency was evaluated at baseline and after irradiation with 1-Gy gamma rays from a 137Cs source. The results show a non significant increase of frequency of micronucleated binucleated lymphocytes in cancer patients compared with the controls at baseline (Mean (S.E.): 16.8 (0.7) vs 15.7 (0.5), but not after irradiation (Mean (S.E.): 145.8 (3.0) vs 154.0 (2.6)). Neither a family history of breast cancer nor the presence of a pathogenic mutation in BRCA1/2 genes were associated with an increased micronuclei frequency. Our results do not support a significant role of micronucleus frequency as a biomarker of breast cancer risk/susceptibility.

  10. Genotoxic and cytotoxic evaluation of Jatropha dioica Sessé ex Cerv. by the micronucleus test in mouse peripheral blood.

    Science.gov (United States)

    Araujo-Espino, Diana Isela; Zamora-Perez, Ana Lourdes; Zúñiga-González, Guillermo Moisés; Gutiérrez-Hernández, Rosalinda; Morales-Velazquez, Gabriela; Lazalde-Ramos, Blanca Patricia

    2017-03-23

    Jatropha dioica Sessé ex Cerv. is a medicinal plant credited with low cytotoxicity in vitro. Thus, the objective of this work was to evaluate the possible genotoxic and cytotoxic effect in vivo of the J. dioica aqueous extract by means of micronucleus assay in mouse peripheral blood. Four different J. dioica aqueous extract dose-units were evaluated (30, 60, 100, and 300 mg/kg). The extract was administered orally to male Balb-C-strain mice every 24 h during 5 days. Blood samples were taken at 0, 24, 48, 72, 96, and 120 h from the mouse's tail and were performed in duplicate extensions. The number of Polychromatic Erythrocytes (PCE), Polychromatic Micronucleus Erythrocytes (PCEMN), and Micronucleus Erythrocytes (MNE) was determined at the different sampling times in the different study groups. Our results showed that the group that received 60 mg/kg of cyclophosphamide (positive control) presented a significant decrease in the PCE (p = 0.044) proportion and a significant increase in MNE (p = 0.032, p = 0.0001). The groups that received the different J. dioica aqueous extract doses did not present either a PCE decrease or an increase in PCEMN and MNE. J. dioica exerts neither a genotoxic nor a cytotoxic effect on mouse peripheral blood at high doses.

  11. The Effects of Cleistanthoside A Tetraacetate Synthesis on Acute Toxicity and Bone Marrow Micronucleus in ICR Mice

    Directory of Open Access Journals (Sweden)

    Pranom PUCHADAPIROM

    2015-07-01

    Full Text Available Phyllanthus taxodiifolius Beille is used in traditional medicine in tropical and subtropical areas. Although it has been used as a folk medicine for a long time, studies on its safety have been limited. In this study, the bone marrow micronucleus and oral toxicity of Cleistanthoside A tetraacetate, a modified arylnaphthalide lignan of Cleistanthoside A from the P. taxodiifolius Beille, were evaluated. Imprinting control region (ICR female mice were orally administered Cleistanthoside A tetraacetate at doses of 250, 500 and 1,000 mg/kg body weight (BW. Signs of toxicity, bone marrow micronucleus, clinical blood chemistry, and histopathological findings were determined after treatment. No mortality was observed in any of the groups. A significant increase in numbers of bone marrow micronucleus, marked elevation of alkaline phosphatase (ALP, blood urea nitrogen (BUN, and creatinine (CRE were observed in the mice administered with Cleistanthoside A tetraacetate 1,000 mg/kg BW. These results also correlated with the histopathological scoring of liver and kidney cells in ICR mice. The mice administered with Cleistanthoside A tetraacetate 1,000 mg/kg BW had high toxicity in the liver and kidneys. Long term or chronic toxicity should be further studied for safety.

  12. A new prenylated flavanonol from Seseli annuum roots showing protective effect on human lymphocytes DNA.

    Science.gov (United States)

    Vucković, Ivan; Vajs, Vlatka; Stanković, Miroslava; Tesević, Vele; Milosavljević, Slobodan

    2010-03-01

    A new prenylated flavanonol named seselinonol (1) was isolated from the roots of Seseli annuum, together with the well-known biologically active polyacetylenes falcarinol (2) and falcarindiol (3), and the prenylated furanocoumarin phellopterin (4). Its structure was elucidated by extensive spectroscopic analysis, including HR-ESI-MS, 1D- and 2D-NMR. Seselinonol and phellopterin were tested for in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using cytochalasin-B blocked micronucleus (CBMN) assay. The new compound exerted a beneficial effect by decreasing DNA damage of human lymphocytes.

  13. Excised radicle tips as a source of genomic DNA for PCR-based genotyping and melting curve analysis in cotton

    Indian Academy of Sciences (India)

    P Srinivasa Rao; P Sateesh Kumar; Ramesh V Sonti

    2013-03-01

    Genomic DNA isolation in cotton is complicated because of the presence of secondary metabolites that are inhibitory to PCR amplification. We report here that radicle tips, but not other parts of cotton seedlings, yield high-quality DNA that is readily amenable for PCR. The radicle-tip-excised seedlings retain viability because of the formation of adventitious roots. We demonstrate the utility of this method in distinguishing homozygotes from heterozygotes in a cotton breeding population and in hybrid seed purity testing.

  14. Positive Root Bounds and Root Separation Bounds

    Science.gov (United States)

    Herman, Aaron Paul

    In this thesis, we study two classes of bounds on the roots of a polynomial (or polynomial system). A positive root bound of a polynomial is an upper bound on the largest positive root. A root separation bound of a polynomial is a lower bound on the distance between the roots. Both classes of bounds are fundamental tools in computer algebra and computational real algebraic geometry, with numerous applications. In the first part of the thesis, we study the quality of positive root bounds. Higher quality means that the relative over-estimation (the ratio of the bound and the largest positive root) is smaller. We find that all known positive root bounds can be arbitrarily bad. We then show that a particular positive root bound is tight for certain important classes of polynomials. In the remainder of the thesis, we turn to root separation bounds. We observe that known root separation bounds are usually very pessimistic. To our surprise, we also find that known root separation bounds are not compatible with the geometry of the roots (unlike positive root bounds). This motivates us to derive new root separation bounds. In the second part of this thesis, we derive a new root separation for univariate polynomials by transforming a known bound into a new improved bound. In the third part of this thesis, we use a similar strategy to derive a new improved root separation bound for polynomial systems.

  15. Intraspecific variation in root and leaf traits and leaf-root trait linkages in eight aspen demes (Populus tremula and P. tremuloides).

    Science.gov (United States)

    Hajek, Peter; Hertel, Dietrich; Leuschner, Christoph

    2013-01-01

    Leaf and fine root morphology and physiology have been found to vary considerably among tree species, but not much is known about intraspecific variation in root traits and their relatedness to leaf traits. Various aspen progenies (Populus tremula and P. tremuloides) with different growth performance are used in short-rotation forestry. Hence, a better understanding of the link between root trait syndromes and the adaptation of a deme to a particular environment is essential in order to improve the match between planted varieties and their growth conditions. We examined the between-deme (genetic) and within-deme (mostly environmental) variation in important fine root traits [mean root diameter, specific root area (SRA) and specific root length (SRL), root tissue density (RTD), root tip abundance, root N concentration] and their co-variation with leaf traits [specific leaf area (SLA), leaf size, leaf N concentration] in eight genetically distinct P. tremula and P. tremuloides demes. Five of the six root traits varied significantly between the demes with largest genotypic variation in root tip abundance and lowest in mean root diameter and RTD (no significant difference). Within-deme variation in root morphology was as large as between-deme variation suggesting a relatively low genetic control. Significant relationships existed neither between SLA and SRA nor between leaf N and root N concentration in a plant. Contrary to expectation, high aboveground relative growth rates (RGR) were associated with large, and not small, fine root diameters with low SRA and SRL. Compared to leaf traits, the influence of root traits on RGR was generally low. We conclude that aspen exhibits large intraspecific variation in leaf and also in root morphological traits which is only partly explained by genetic distances. A root order-related analysis might give deeper insights into intraspecific root trait variation.

  16. Initiation and elongation of lateral roots in Lactuca sativa

    Science.gov (United States)

    Zhang, N.; Hasenstein, K. H.

    1999-01-01

    Lactuca sativa cv. Baijianye seedlings do not normally produce lateral roots, but removal of the root tip or application of auxin, especially indole-butyric acid, triggered the formation of lateral roots. Primordia initiated within 9 h and were fully developed after 24 h by activating the pericycle cells opposite the xylem pole. The pericycle cells divided asymmetrically into short and long cells. The short cells divided further to form primordia. The effect of root tip removal and auxin application was reversed by 6-benzylaminopurine at concentrations >10(-8) M. The cytokinin oxidase inhibitor N1-(2chloro4pyridyl)-N2-phenylurea also suppressed auxin-induced lateral rooting. The elongation of primary roots was promoted by L-alpha-(2-aminoethoxyvinyl) glycine and silver ions, but only the latter enhanced elongation of lateral roots. The data indicate that the induction of lateral roots is controlled by basipetally moving cytokinin and acropetally moving auxin. Lateral roots appear to not produce ethylene.

  17. Initiation and elongation of lateral roots in Lactuca sativa

    Science.gov (United States)

    Zhang, N.; Hasenstein, K. H.

    1999-01-01

    Lactuca sativa cv. Baijianye seedlings do not normally produce lateral roots, but removal of the root tip or application of auxin, especially indole-butyric acid, triggered the formation of lateral roots. Primordia initiated within 9 h and were fully developed after 24 h by activating the pericycle cells opposite the xylem pole. The pericycle cells divided asymmetrically into short and long cells. The short cells divided further to form primordia. The effect of root tip removal and auxin application was reversed by 6-benzylaminopurine at concentrations >10(-8) M. The cytokinin oxidase inhibitor N1-(2chloro4pyridyl)-N2-phenylurea also suppressed auxin-induced lateral rooting. The elongation of primary roots was promoted by L-alpha-(2-aminoethoxyvinyl) glycine and silver ions, but only the latter enhanced elongation of lateral roots. The data indicate that the induction of lateral roots is controlled by basipetally moving cytokinin and acropetally moving auxin. Lateral roots appear to not produce ethylene.

  18. The effects of fungicide benomyl (benlate) on growth and mitosis in onion (Allium cepa L.) root apical meristem.

    Science.gov (United States)

    Dane, F; Dalgiç, O

    2005-01-01

    In this study, the effects of benomyl, a systemic fungicide were investigated in the mitotic cell division in onion (Allium cepa) root tip cells during germination. For this aim, different concentrations (1, 2, 5, 10 and 20 mM) of benomyl solutions were used. All the concentrations used caused several abnormalities in mitotic cell divisions and the mitotic frequency in the onion root tip cells decreased as the concentration of benomyl solution increased. Based on our findings, it is reported that benomyl has some negative effects on mitotic divisions in onion root tip cells.

  19. Root elongation against a constant force: experiment with a computerized feedback-controlled device

    Science.gov (United States)

    Kuzeja, P. S.; Lintilhac, P. M.; Wei, C.

    2001-01-01

    Axial force was applied to the root tip of corn (Zea mays L. cv. Merit) seedlings using a computerized, feedback-controlled mechanical device. The system's feedback capability allowed continuous control of a constant tip load, and the attached displacement transducer provided the time course of root elongation. Loads up to 7.5 g decreased the root elongation rate by 0.13 mm h-1 g-1, but loads 7.5 to 17.5 g decreased the growth rate by only 0.04 mm h-1 g-1. Loads higher than 18 g stopped root elongation completely. Measurement of the cross-sectional areas of the root tips indicated that the 18 g load had applied about 0.98 MPa of axial pressure to the root, thereby exceeding the root's ability to respond with increased turgor pressure. Recorded time-lapse images of loaded roots showed that radial thickening (swelling) occurred behind the root cap, whose cross-sectional area increased with tip load.

  20. The Belgian coal tips: geomorphic and pedogenetic research with community service and educational aspects

    Science.gov (United States)

    Nyssen, Jan; Vermeersch, Dominiek; Diependaele, Stijn; van Ranst, Eric; Derycke, Anja; Corexenos, Pavlos; Palmers, Jo; Poesen, Jean

    2010-05-01

    Coal tips are composed of various materials, essentially sterile rock but also waste such as mine wood, scrap metal as well as scoria from surface facilities. Rocks composing Belgian coal tips belong to the Westfalian and Namurian (approx. 320 Ma) and include psammites, schists and coal residues. Currently, these coal tips are increasingly regarded as socio-cultural heritage. Worldwide, several studies have focused on the factors controlling the magnitude of geomorphic processes, such as nature of slope material, vegetation type and cover, the role of self-ignition and combustion, time and slope gradient. In the international literature, research gaps concern particular processes, such as causes and consequences of the widespread tree toppling and root throw, rock fragment movement at the surface, or gully control by check dams. Especially spatially distributed erosion rates by the various processes active on coal tips, neither sediment budgets seem ever to have been established. The same holds for regional (subcontinental) variability in slope processes on coal tips. The many Belgian coal tips that have not been levelled provide a unique opportunity for geomorphological and pedogenetical studies, which have so far demonstrated the existence of: - correlations between the intensity of observed geomorphic processes and a broad range of bio-physical explanatory factors; - strong and reciprocal influences between the vegetation of coal tips and the morphology of the colonised slopes; - absence of strong relations between gully activity and slope angle, resulting from the narrow range of slope gradients on coal tips; - possibilities to locate landslide risk zones through combined use of Digital Elevation Models and thermographic imagery; - presence of neoformed minerals on burning/burned coal tips, which impact the soil forming processes as well as soil quality.

  1. Canal enlargement by Er:YAG laser using a cone-shaped irradiation tip.

    Science.gov (United States)

    Shoji, S; Hariu, H; Horiuchi, H

    2000-08-01

    To solve the problem of mechanical instrumentation, we developed a cone-shaped laser irradiation tip. This tip delivers 80% of the energy of the laser laterally and 20% of the energy forward. The tip was equipped with a water nozzle. The aim of this study was to examine the effect of Er:YAG laser irradiation using this tip on root canal enlargement and debridement. As a root canal model, a hole (0.5 x 5 mm) was drilled into a bovine dentin block. The tip was inserted into this hole and moved from the apex to the orifice (45 mm/min). The power of 10 mJ x 10 pps caused enlargement of the canal dimension by 106.5%. 20 and 40 mJ x 10 pps caused enlargements of 116.3 and 118.6%. 30 mJ x 10 pps caused the biggest change (129.8%). Scanning electron microscopic observations indicated that the dentin surface after laser preparation appeared cleaner than that obtained after preparation by drilling. This technique may have the advantage of decreasing the preparation time.

  2. Acetylcholinesterase inhibition and micronucleus frequency in oysters (Crassostrea corteziensis exposed to chlorpyrifos

    Directory of Open Access Journals (Sweden)

    AB Benitez-Trinidad1

    2014-09-01

    Full Text Available Chlorpyrifos (CPF is an Organophosphorous pesticide (OP that has been widely used for both agricultural and domestic pest control. To date, there is little information regarding the effects of this pesticide on aquatic organisms, particularly oysters. The aim of this study was to evaluate Acetylcholinesterase (AChE activity and Micronucleus (MN frequency in the oyster Crassostrea corteziensis in laboratory exposure with CPF (20, 40, 60, 80, and 160 μg/L and in a field study. The results showed that AChE was reduced 60 - 82 % in oysters exposed to CPF, relative to the negative control. Similar AChE results were observed in oysters collected from the Boca de Camichín Estuary in Nayarit, Mexico; with respect to genetic damage, evaluated through MN, treatment with CPF did not induce the MN frequency, nor did the oyster from the field study exhibit an increase in this biomarker. These results suggest that C. corteziensis is a sensitive model for evaluating the acute toxicity of OP in laboratory studies as well in the field. In addition, it generates prospects on studying mechanisms through which the oyster could possess resistance to genotoxic agents, as well as its being a reliable model for evaluating the genotoxic effects of xenobiotics through the MN technique.

  3. Chromosome aberrations, micronucleus and sperm head abnormalities in mice treated with natamycin, [corrected] a food preservative.

    Science.gov (United States)

    Rasgele, Pinar Goc; Kaymak, Fisun

    2010-03-01

    Natamycin [corrected] is used as preservative in foods. The genotoxic effects of the food preservative natamycin [corrected] were evaluated using chromosome aberrations and micronucleus test in bone marrow cells and sperm head abnormality assays in mice. Blood samples were taken from mice and levels of total testosterone in serum were also determined. Natamycin [corrected] was intraperitoneally (ip) injected at 200, 400 and 800 mg/kg. Natamycin [corrected] did not induce chromosome aberrations but significantly increased the number of micronucleated polychromatic erythrocytes in bone marrow and sperm head abnormalities at all concentrations and treatment periods. It also decreased MI at all concentrations for 6, 12 and 24h treatment periods. Natamycin [corrected] decreased PCE/NCE ratio at all concentrations for 48h in female mice, for 24 and 48h treatment periods in male mice. At the 800 mg/kg concentration, natamycin [corrected] decreased PCE/NCE ratio for 24 and 72h in female mice. A dose dependent increase was observed in the percentage of sperm head abnormalities. The levels of serum testosterone decreased dose-dependently. The obtained results indicate that natamycin [corrected] is not clastogenic, but it is aneugenic in mice bone marrow and it is a potential germ cell mutagen in sperm cells.

  4. Synergistic interaction of radiation and octylphenol evaluated by tradescantia-micronucleus assay

    Energy Technology Data Exchange (ETDEWEB)

    Shin, H. S.; Lee, J. H. [Chungnam National University, Taejon (Korea, Republic of); Lee, B. H.; Kim, J. K. [KAERI, Taejon (Korea, Republic of)

    2003-07-01

    Many kinds of synthetic chemicals have been being used for various purposes. Some of them are called 'endocrine disruptors' because they can disturb the endocrine system of organisms. Presently no technique is established for the quantitative assessment of biological risk of the environmental hormones. The pollen mother cells (PMC) of tradescantia are very sensitive to chemical toxicants or ionizing radiation, and thus can be used as a biological end- point for assessing their effects. Micronucleus frequencies in PMC showed a good dose- and concentration-response relationship for radiation and bisphenol A. The MCN frequencies in the pollen mother cells treated with octylphenol were 4.20, 7.27, 4.93 MCN/100 tetrads for 1, 5 and 10 {mu}M, respectively. On the other hand, the frequencies were 10.13, 19.27, 24.47 MCN/100 tetrads for the octylphenol treatments (1, 5, and 10 {mu}M) combined with 30 cGy irradiation. The MCN frequency of 30 cGy control was 8.00 MCN/100 tetrads for the octylphenol treatments (1, 5, and 10{mu}M) combined with 30 cGy irradiation. The MCN frequency of 30 cGy control was 8.00 MCN/100 tetrads. It is known from the result that the Trad-MCN assay can be an excellent tool for the detection of biologically harmful effects of environmental toxicants or synthetic chemicals.

  5. Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review

    Science.gov (United States)

    Torres-Bugarín, Olivia; Macriz Romero, Nicole; Ramos Ibarra, María Luisa; Flores-García, Aurelio; Valdez Aburto, Penélope; Zavala-Cerna, María Guadalupe

    2015-01-01

    Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies. PMID:26339592

  6. Cytogenotoxicity of Abattoir Effluent in Clarias gariepinus (Burchell, 1822 Using Micronucleus Test

    Directory of Open Access Journals (Sweden)

    Chibuisi G. Alimba

    2015-01-01

    Full Text Available The cytogenotoxic potential of abattoir effluent from Bodija, Nigeria, was investigated using micronucleus test in Clarias gariepinus. Fish was exposed to five different concentrations: 0.2, 0.4, 0.8, 1.6, and 3.1% of the effluent for 7, 14, and 28 days. Tap water and 0.02 mL/L of benzene were used as negative and positive controls, respectively. Physicochemical parameters and heavy metals were analyzed in the effluent in accordance with standard methods. After exposure, blood was collected from the treated and control fish and slides were prepared for micronuclei (MN and nuclear abnormality evaluation in the peripheral erythrocytes. The effluent induced significant (p<0.05 increase in the frequency of MN in a time dependent manner. Similarly, the frequency of total nuclear abnormalities (blebbing, notch, bud, binucleation, and vacuolation was higher in the exposed fish than the negative control. Electrical conductivity, nitrate, biochemical oxygen demand, chemical oxygen demand, arsenic, and copper analyzed in the effluent may have provoked the observed cytogenetic damage. The findings herein suggest the presence of clastogens and cytotoxins in Bodija abattoir wastewater which are capable of increasing genomic instability in aquatic biota.

  7. Influence of counting methodology on erythrocyte ratios in the mouse micronucleus test.

    Science.gov (United States)

    LeBaron, Matthew J; Schisler, Melissa R; Torous, Dorothea K; Dertinger, Stephen D; Gollapudi, B Bhaskar

    2013-04-01

    The mammalian erythrocyte micronucleus test is widely used to investigate the potential interaction of a test substance with chromosomes or mitotic apparatus of replicating erythroblasts. In addition to the primary endpoint, micronucleated erythrocyte frequency, the proportion of immature erythrocytes is measured to assess the influence of treatment on erythropoiesis. The guideline recommendation for an acceptable limit of the immature erythrocyte fraction of not < 20% of the controls was based on traditional scoring methods that consider RNA content. Flow-based sample analysis (e.g., MicroFlow®) characterizes a subpopulation of RNA-containing reticulocytes (RETs) based on CD71 (transferrin receptor) expression. As CD71+ cells represent a younger cohort of RETs, we hypothesized that this subpopulation may be more responsive than the RNA+ fraction for acute exposures. This study evaluated RET population in the peripheral blood of two strains of mice treated by oral gavage with three clastogens (cyclophosphamide, N-ethyl-N-nitrosourea, and methyl methanesulfonate). Although CD71+ frequencies correlated with RNA-based counts, the relative treatment-related reductions were substantially greater. Accordingly, when using the flow cytometry-based CD71+ values for scoring RETs in an acute treatment design, it is suggested that a target value ≥ 5% CD71+ reticulocytes (i.e., 95% depression in reticulocytes proportion) be considered as acceptable for a valid assay.

  8. Repeated-dose liver micronucleus test of 4,4'-methylenedianiline using young adult rats.

    Science.gov (United States)

    Sanada, Hisakazu; Koyama, Naomi; Wako, Yumi; Kawasako, Kazufumi; Hamada, Shuichi

    2015-03-01

    Liver micronucleus (MN) tests using partial hepatectomized rats or juvenile rats have been shown to be useful for the detection of hepatic carcinogens. Moreover, Narumi et al. established the repeated-dose liver MN test using young adult rats for integration into general toxicity. In the present study, in order to examine the usefulness of the repeated-dose liver MN test, we investigated MN induction with a 14 or 28 day treatment protocol using young adult rats treated with 4,4′-methylenedianiline (MDA), a known hepatic carcinogen. MDA dose-dependently induced micronuclei in hepatocytes in 14- and 28-day repeated-dose tests. However, although statistically significant increases in micronuclei were observed in bone marrow cells at two dose levels in the 14-day study, there was no dose response and no increases in micronuclei in the 28-day study. These results indicate that the evaluation of genotoxic effects using hepatocytes is effective in cases where chromosomal aberrations are not clearly detectable in bone marrow cells. Moreover, the repeated-dose liver MN test allows evaluation at a dose below the maximum tolerable dose, which is required for the conventional MN test because micronucleated hepatocytes accumulate. The repeated-dose liver MN test employed in the present study can be integrated into the spectrum of general toxicity tests without further procedural modifications.

  9. Micronucleus test in rodent tissues other than liver or erythrocytes: Report of the IWGT working group.

    Science.gov (United States)

    Uno, Yoshifumi; Morita, Takeshi; Luijten, Mirjam; Beevers, Carol; Hamada, Shuichi; Itoh, Satoru; Ohyama, Wakako; Takasawa, Hironao

    2015-05-01

    At the 6th International Workshop on Genotoxicity Testing, the liver micronucleus test (MNT) working group briefly discussed the MNT using tissues other than liver/erythrocytes. Many tissues other than liver/erythrocytes have been studied, primarily for research purposes. They have included the colon and intestinal epithelium, skin, spleen, lung, stomach, bladder, buccal mucosa, vagina, and fetal/neonatal tissues. These tissues were chosen because they were target sites of carcinogens, and/or relevant to a specific route of exposure. Recently, there has been particular focus on the gastrointestinal (GI) tract as it is a contact site associated with high exposure following oral gavage. Furthermore GI tumors are observed with high frequency in human populations. A collaborative study of the rat glandular stomach and colon MNT was conducted in conjunction with a collaborative study of the repeated-dose liver MNT. Based on limited data currently available, the rodent MNT using the glandular stomach and/or colon seems to detect genotoxic carcinogens with GI tract target-organ specificity. The working group concluded that the GI tract MNT would be a promising method to examine clastogenicity or aneugenicity of test chemicals in the stomach and/or colon. Further data will be needed to fully establish the methods, and to identify the sensitivity and specificity of the GI tract MNT.

  10. Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review

    Directory of Open Access Journals (Sweden)

    Olivia Torres-Bugarín

    2015-01-01

    Full Text Available Autoimmune diseases (AD are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies.

  11. Genotoxicity assessment of cobalt chloride in Eisenia hortensis earthworms coelomocytes by comet assay and micronucleus test.

    Science.gov (United States)

    Ciğerci, İbrahim Hakkı; Ali, Muhammad Muddassir; Kaygısız, Şöhret Yüksek; Liman, Recep

    2016-02-01

    Cobalt and its different compounds are extensively used worldwide and considered as possible environmental pollutant. Earthworms are useful model organism and its different species are used to monitor soil pollution. No study has been found to detect cobalt chloride (CoCl2) genotoxicity in earthworms. So, current study aimed to evaluate CoCl2 induced genotoxicity in Eisenia hortensis earthworms coelomocytes by alkaline comet assay (CA) and micronucleus (MN) test. The earthworms (n = 10 for each group) were exposed to different series of CoCl2 concentrations (100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm) to find LD50. The LD50 for CoCl2 was found at 226 ppm. Then, doses of LD50/2, LD50 and 2XLD50 for 48 h were used. CA and MN demonstrated the significant increase (P < 0.05) in DNA damage and chromosomal aberrations. Dose dependent relationship was found. Highest DNA damage and chromosomal aberrations were noticed at 2XLD50. The results concluded that CoCl2 induced DNA damage, cytokinesis failure and chromosomal aberrations in E. hortensis earthworms.

  12. Fluorescence in situ hybridization in combination with the comet assay and micronucleus test in genetic toxicology

    Directory of Open Access Journals (Sweden)

    Hovhannisyan Galina G

    2010-09-01

    Full Text Available Abstract Comet assay and micronucleus (MN test are widely applied in genotoxicity testing and biomonitoring. While comet assay permits to measure direct DNA-strand breaking capacity of a tested agent MN test allows estimating the induced amount of chromosome and/or genome mutations. The potential of these two methods can be enhanced by the combination with fluorescence in situ hybridization (FISH techniques. FISH plus comet assay allows the recognition of targets of DNA damage and repairing directly. FISH combined with MN test is able to characterize the occurrence of different chromosomes in MN and to identify potential chromosomal targets of mutagenic substances. Thus, combination of FISH with the comet assay or MN test proved to be promising techniques for evaluation of the distribution of DNA and chromosome damage in the entire genome of individual cells. FISH technique also permits to study comet and MN formation, necessary for correct application of these methods. This paper reviews the relevant literature on advantages and limitations of Comet-FISH and MN-FISH assays application in genetic toxicology.

  13. Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review.

    Science.gov (United States)

    Torres-Bugarín, Olivia; Macriz Romero, Nicole; Ramos Ibarra, María Luisa; Flores-García, Aurelio; Valdez Aburto, Penélope; Zavala-Cerna, María Guadalupe

    2015-01-01

    Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies.

  14. Genotoxic evaluation of Halfenprox using the human peripheral lymphocyte micronucleus assay and the Ames test.

    Science.gov (United States)

    Akyıl, Dilek; Eren, Yasin; Konuk, Muhsin; Dere, Hatice; Serteser, Ahmet

    2017-04-01

    The genotoxicity and mutagenicity of Halfenprox, a synthetic pyrethroid insecticide and acaricide, was assessed using two standard genotoxicity assays of the Salmonella typhimurium mutagenicity assay (Ames test) and in vitro micronucleus (MN) assay in human peripheral lymphocytes. In the Ames test, Salmonella strains TA98 and TA100 were treated with or without S9 fraction. The doses of Halfenprox were 6.25, 12.5, 25, 50, and 100 μg/plate and test materials were dissolved in DMSO. The concentrations of Halfenprox did not show mutagenic activity on both strains with and without S9 fraction. The MN assay was used to investigate the genotoxic effects of Halfenprox in human peripheral lymphocytes treated with 250, 500, 750, and 1000 μg/ml concentrations of Halfenprox for 24 and 48 h, and at 1000 μg/ml the concentration was significantly increased and the MN formation was compared with the negative control for both treatment periods. In addition, a significant decrease of the nuclear devision index (NDI) values at the higher concentrations of Halfenprox and at both treatment periods was observed.

  15. Micronucleus test for radiation biodosimetry in mass casualty events: Evaluation of visual and automated scoring

    Energy Technology Data Exchange (ETDEWEB)

    Bolognesi, Claudia, E-mail: claudia.bolognesi@istge.i [Environmental Carcinogenesis Unit, National Cancer Research Institute, Largo R. Benzi 10, 16132 Genoa (Italy); Balia, Cristina; Roggieri, Paola [Environmental Carcinogenesis Unit, National Cancer Research Institute, Largo R. Benzi 10, 16132 Genoa (Italy); Cardinale, Francesco [Clinical Epidemiology Unit, National Cancer Research Institute, Largo R. Benzi 10, 16132 Genoa (Italy); Department of Health Sciences, University of Genoa, Genoa (Italy); Bruzzi, Paolo [Clinical Epidemiology Unit, National Cancer Research Institute, Largo R. Benzi 10, 16132 Genoa (Italy); Sorcinelli, Francesca [Environmental Carcinogenesis Unit, National Cancer Research Institute, Largo R. Benzi 10, 16132 Genoa (Italy); Laboratory of Genetics, Histology and Molecular Biology Section, Army Medical and Veterinary, Research Center, Via Santo Stefano Rotondo 4, 00184 Roma (Italy); Lista, Florigio [Laboratory of Genetics, Histology and Molecular Biology Section, Army Medical and Veterinary, Research Center, Via Santo Stefano Rotondo 4, 00184 Roma (Italy); D' Amelio, Raffaele [Sapienza, Universita di Roma II Facolta di Medicina e Chirurgia and Ministero della Difesa, Direzione Generale Sanita Militare (Italy); Righi, Enzo [Frascati National Laboratories, National Institute of Nuclear Physics, Via Enrico Fermi 40, 00044 Frascati, Rome (Italy)

    2011-02-15

    In the case of a large-scale nuclear or radiological incidents a reliable estimate of dose is an essential tool for providing timely assessment of radiation exposure and for making life-saving medical decisions. Cytogenetics is considered as the 'gold standard' for biodosimetry. The dicentric analysis (DA) represents the most specific cytogenetic bioassay. The micronucleus test (MN) applied in interphase in peripheral lymphocytes is an alternative and simpler approach. A dose-effect calibration curve for the MN frequency in peripheral lymphocytes from 27 adult donors was established after in vitro irradiation at a dose range 0.15-8 Gy of {sup 137}Cs gamma rays (dose rate 6 Gy min{sup -1}). Dose prediction by visual scoring in a dose-blinded study (0.15-4.0 Gy) revealed a high level of accuracy (R = 0.89). The scoring of MN is time consuming and requires adequate skills and expertise. Automated image analysis is a feasible approach allowing to reduce the time and to increase the accuracy of the dose estimation decreasing the variability due to subjective evaluation. A good correlation (R = 0.705) between visual and automated scoring with visual correction was observed over the dose range 0-2 Gy. Almost perfect discrimination power for exposure to 1-2 Gy, and a satisfactory power for 0.6 Gy were detected. This threshold level can be considered sufficient for identification of sub lethally exposed individuals by automated CBMN assay.

  16. In-vitro carbofuran induced micronucleus formation in human blood lymphocytes.

    Science.gov (United States)

    Sharma, R K; Rai, D K; Sharma, B

    2012-12-22

    The farmers in general get exposed to different chemicals including pesticides. Many of these compounds are capable of inducing mutations in DNA and lead to several diseases including cancer. Carbofuran is a broad spectrum pesticide and frequently used in agricultural practices in India. In this study we intended to evaluate DNA damage inflicted by pesticide exposure in human blood lymphocytes under in vitro condition. The lymphocytes were exposed to varying concentrations of carbofuran (0—50μM) and analyzed by means of the micronucleus (MN) test. The results obtained showed significant increase in MN frequency after exposure to 5, 10, 25 and 50μM of carbofuran as compared to the control group. The frequencies of MN were observed to be in concentration dependent manner. As we further increase the concentration of carbofuran, we observed significant decrease in the mean percentage of binucleated cells (70—49%) and increase in the number of micronuclei formed per 1000 binucleated cells. Simultaneously, we also observed reduction in Cytokinesis—Block Proliferation index (CBPI) with increase in the carbofuran concentrations. The results indicate that this pesticide may exhibit genotoxic effect at higher concentrations. This study emphasizes the need to reinforce the good practices campaigns in order to enlighten those who work with pesticides and also to make them aware about the importance of using protective measures.

  17. Effects of heavy metals/metalloids contamination of soils on micronucleus induction in Tradescantia pallida

    Directory of Open Access Journals (Sweden)

    Neelima Meravi

    2013-06-01

    Full Text Available The present study was conducted in GGV campus, Bilaspur in which heavy metals/metalloids speciation of soil (for Cr, Fe, Ni, Cd and Pb was performed for assessing the genotoxicity of these metals. The metals concentrations were measured with the help of AAS 7000 (Shimadzu and the standard solution was prepared using standard metal solution of Inorganic Ventures. The concentrations of Cr, Fe, Ni, Cd and Pb (in ug/100 g soil were 12.4, 33.9, 3.1, 0.07 and 2.4 respectively. The flowers of Tradescantia pallida plants growing in this soil were taken and their micronucleus (Trad-MCN bioassay was performed. Trad-MCN bioassay was performed using the protocols established by Ma (1981. The study revealed that at these concentrations of metals micronuclei (stained objects that were smaller than the nuclei and not connected to the nuclei are classified as MCN were formed. Therefore it can be inferred from the present study that soil of GGV campus is genotoxic for the Tradescantia pallida.

  18. Application of micronucleus test and comet assay to evaluate BTEX biodegradation.

    Science.gov (United States)

    Mazzeo, Dânia Elisa Christofoletti; Matsumoto, Silvia Tamie; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

    2013-01-01

    The BTEX (benzene, toluene, ethylbenzene and xylene) mixture is an environmental pollutant that has a high potential to contaminate water resources, especially groundwater. The bioremediation process by microorganisms has often been used as a tool for removing BTEX from contaminated sites. The application of biological assays is useful in evaluating the efficiency of bioremediation processes, besides identifying the toxicity of the original contaminants. It also allows identifying the effects of possible metabolites formed during the biodegradation process on test organisms. In this study, we evaluated the genotoxic and mutagenic potential of five different BTEX concentrations in rat hepatoma tissue culture (HTC) cells, using comet and micronucleus assays, before and after biodegradation. A mutagenic effect was observed for the highest concentration tested and for its respective non-biodegraded concentration. Genotoxicity was significant for all non-biodegraded concentrations and not significant for the biodegraded ones. According to our results, we can state that BTEX is mutagenic at concentrations close to its water solubility, and genotoxic even at lower concentrations, differing from some described results reported for the mixture components, when tested individually. Our results suggest a synergistic effect for the mixture and that the biodegradation process is a safe and efficient methodology to be applied at BTEX-contaminated sites.

  19. Phacoemulsification efficiency with a radiused phaco tip.

    Science.gov (United States)

    Gupta, Isha; Zaugg, Brian; Stagg, Brian C; Barlow, William R; Pettey, Jeff H; Jensen, Jason D; Kirk, Kevin R; Olson, Randall J

    2014-05-01

    To evaluate radiused and nonradiused phacoemulsification tips to determine which tip is more efficient in removal of lens fragments using 3 ultrasound (US) modalities. John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA. Experimental study. Porcine lens nuclei were formalin-soaked for 2 hours or 3 hours and then divided into 2.0 mm cubes. Thirty-degree, 0.9 mm beveled radiused tips and nonradiused tips were used with torsional, transverse, and micropulsed US modalities. Bent tips were used with torsional and transversal US, and straight tips were used with micropulsed US. Efficiency (time to lens removal) and chatter (number of lens fragment repulsions from the tip) were determined. The mean phacoemulsification efficiency was statistically significantly decreased (increased time for removal) with the radiused tip compared with the nonradiused tip for torsional US only (2-hour soaked lenses: 2.14 seconds ± 1.94 [SD] versus 1.18 ± 0.69 seconds [P tip showed decreased efficiency with torsional US only. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  20. Aluminium-induced reduction of plant growth in alfalfa (Medicago sativa) is mediated by interrupting auxin transport and accumulation in roots.

    Science.gov (United States)

    Wang, Shengyin; Ren, Xiaoyan; Huang, Bingru; Wang, Ge; Zhou, Peng; An, Yuan

    2016-07-20

    The objective of this study was to investigate Al(3+)-induced IAA transport, distribution, and the relation of these two processes to Al(3+)-inhibition of root growth in alfalfa. Alfalfa seedlings with or without apical buds were exposed to 0 or 100 μM AlCl3 and were foliar sprayed with water or 6 mg L(-1) IAA. Aluminium stress resulted in disordered arrangement of cells, deformed cell shapes, altered cell structure, and a shorter length of the meristematic zone in root tips. Aluminium stress significantly decreased the IAA concentration in apical buds and root tips. The distribution of IAA fluorescence signals in root tips was disturbed, and the IAA transportation from shoot base to root tip was inhibited. The highest intensity of fluorescence signals was detected in the apical meristematic zone. Exogenous application of IAA markedly alleviated the Al(3+)-induced inhibition of root growth by increasing IAA accumulation and recovering the damaged cell structure in root tips. In addition, Al(3+) stress up-regulated expression of AUX1 and PIN2 genes. These results indicate that Al(3+)-induced reduction of root growth could be associated with the inhibitions of IAA synthesis in apical buds and IAA transportation in roots, as well as the imbalance of IAA distribution in root tips.

  1. Auxin, ethylene and the regulation of root growth under mechanical impedance

    Science.gov (United States)

    Sharma, Rameshwar; Santisree, Parankusam; Nongmaithem, Sapana; Sreelakshmi, Yellamaraju

    2012-07-01

    Among the multitude functions performed by plant roots, little information is available about the mechanisms that allow roots to overcome the soil resistance, in order to grow in the soil to obtain water and nutrient. Tomato (Solanum lycopersicum) seedlings grown on horizontally placed agar plates showed a progressive decline in the root length with the increasing impedance of agar media. The incubation with 1-methylcyclopropane (1-MCP), an inhibitor of ethylene perception, led to aerial growth of roots. In contrast, in absence of 1-MCP control roots grew horizontally anchored to the agar surface. Though 1-MCP-treated and control seedlings showed differential ability to penetrate in the agar, the inhibition of root elongation was nearly similar for both treatments. While increased mechanical impedance also progressively impaired hypocotyl elongation in 1-MCP treated seedlings, it did not affect the hypocotyl length of control seedlings. The decline in root elongation was also associated with increased expression of DR5::GUS activity in the root tip signifying accumulation of auxin at the root tip. The increased expression of DR5::GUS activity in the root tip was also observed in 1-MCP treated seedlings, indicating independence of this response from ethylene signaling. Our results indicate operation of a sensing mechanism in root that likely operates independently of ethylene but involves auxin to determine the degree of impedance of the substratum.

  2. Spiralizations and tropisms in Arabidopsis roots.

    Science.gov (United States)

    Migliaccio, F; Piconese, S

    2001-12-01

    When Arabidopsis seedlings are grown on a hard-agar plate, their primary roots show characteristic spiralling movements, apparent as waves, coils and torsions, together with a slanting toward the right-hand side. All these movements are believed to be the result of three different processes acting on the roots: circumnutation, positive gravitropism and negative thigmotropism. The basic movement of the roots is described as that of a growing right-handed helix, which, because of the root tip hitting the agar plate, is continuously switched from the right-hand to the left-hand of the growth direction, and vice versa. This movement also produces a slanting root-growth direction toward the right-hand because of the incomplete waves made by the right-handed root to the left-hand. By contrast, the torsions seen in the coils and waves are interpreted as artefacts that form as an adaptation of the three-dimensional root helix to the flat two-dimensional agar surface.

  3. The tip of the iceberg

    DEFF Research Database (Denmark)

    Bjørst, Lill Rastad

    2010-01-01

      Abstract: The tip of the iceberg: Ice as a nonhuman actor of the climate change debate   The global climate change debate has the Arctic as a core region of concern and ice has become a central aspect of discourses. This article discusses ice representations from six different contexts linked...... are represented. Ice becomes a nonhuman actor, framing the discussions, acting in specific ways, and linking hybrid networks. Indeed it is used in diverse platforms by scientists, politicians, governments, NGOs, as well as Inuit hunters and fishermen...

  4. Windows 8 visual quick tips

    CERN Document Server

    McFedries, Paul

    2012-01-01

    Easy-in, easy-out format covers all the bells and whistles of Windows 8 If you want to learn how to work smarter and faster in Microsoft's Windows 8 operating system, this easy-to-use, compact guide delivers the goods. Designed for visual learners, it features short explanations and full-color screen shots on almost every page, and it's packed with timesaving tips and helpful productivity tricks. From enhancing performance and managing digital content to setting up security and much more, this handy guide will help you get more out of Windows 8. Uses full-color screen shots and short, step-by-

  5. Twitter Tips, Tricks, and Tweets

    CERN Document Server

    McFedries, Paul

    2010-01-01

    Maximize your fun and boost your productivity with this updated, full-color guide to tantalizing Twitter tips!. The popularity of Twitter continues to soar, and is fast becoming the most popular social networking site online. Whether you're looking to learn how to set up an account for the first time or are on the prowl for some cool third-party Twitter apps, this full-color guide will boost your entire Twitter experience. Allowing you to communicate with fellow Twitters within a 140-character limit, this fun and fascinating social networking tool is easier than maintaining a blog and quicker

  6. Dark tip-tilt sensing

    CERN Document Server

    Arcidiacono, Carmelo; Viotto, Valentina; Bergomi, Maria; Farinato, Jacopo; Magrin, Demetrio; Dima, Marco; Gullieuszik, Marco; Marafatto, Luca

    2016-01-01

    Dark wavefront sensing in its simplest and more crude form is a quad-cell with a round spot of dark ink acting as occulting disk at the center. This sensor exhibits fainter limiting magnitude than a conventional quad-cell, providing that the size of the occulting disk is slightly smaller than the size of the spot and smaller than the residual jitter movement in closed loop. We present simulations focusing a generic Adaptive Optics system using Natural Guide Stars to provide the tip-tilt signal. We consider a jitter spectrum of the residual correction including amplitudes exceeding the dark disk size.

  7. Aluminum-induced cell death of barley-root border cells is correlated with peroxidase- and oxalate oxidase-mediated hydrogen peroxide production.

    Science.gov (United States)

    Tamás, L; Budíková, S; Huttová, J; Mistrík, I; Simonovicová, M; Siroká, B

    2005-06-01

    The function of root border cells (RBC) during aluminum (Al) stress and the involvement of oxalate oxidase, peroxidase and H(2)O(2) generation in Al toxicity were studied in barley roots. Our results suggest that RBC effectively protect the barley root tip from Al relative to the situation in roots cultivated in hydroponics where RBC are not sustained in the area surrounding the root tip. The removal of RBC from Al-treated roots increased root growth inhibition, Al and Evans blue uptake, inhibition of RBC production, the level of dead RBC, peroxidase and oxalate oxidase activity and the production of H(2)O(2). Our results suggest that even though RBC actively produce active oxygen species during Al stress, their role in the protection of root tips against Al toxicity is to chelate Al in their dead cell body.

  8. Cutting efficiency of apical preparation using ultrasonic tips with microprojections: confocal laser scanning microscopy study.

    Science.gov (United States)

    Kwak, Sang-Won; Moon, Young-Mi; Yoo, Yeon-Jee; Baek, Seung-Ho; Lee, WooCheol; Kim, Hyeon-Cheol

    2014-11-01

    The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. The apical 3-mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

  9. Effects of long-term temperature and nutrient manipulation on Norway spruce fine roots and mycelia production

    DEFF Research Database (Denmark)

    Leppälammi-Kujansuu, J.; Ostonen, I.; Strömgren, M.;

    2013-01-01

    production were determined from soil cores and mesh bags. Results and conclusions The fine root biomass and necromass were highest in the fertilized plots, following similar trends in the above-ground biomass, whereas the EcM root tip biomass per basal area decreased by 22 % in the fertilized plots compared......Aims and methods The effects of changing climate on ectomycorrhizal (EcM) fine roots were studied in northern Sweden by manipulating soil temperature for 14 years and/or by fertilizing for 22 years. Fine root biomass, necromass, EcM root tip biomass, morphology and number as well as mycelia...... to the control. Warming increased the fine root biomass, live/dead-ratio and the number of EcM root tips in the mineral soil and tended to increase the production of EcM mycelia. Greater fine root biomass meant more EcM root tips, although the tip frequency was not affected by fertilization or warming...

  10. Mini-flared Kelman tip, reverse tip, and sidewinder tip with torsional phaco: a prospective randomized comparative study

    National Research Council Canada - National Science Library

    Hida, Wilson Takashi; Tzelikis, Patrick Frensel; Nakano, Celso Takashi; Motta, Antonio Francisco Pimenta; Alves, Milton Ruiz

    2015-01-01

    ...: In this prospective, comparative, masked study, patients were randomly assigned to have torsional coaxial microincision cataract surgery using the mini-flared 45-degree Kelman tip, reversed mini...

  11. Micropropagation of Plantago asiatica L. through culture of shoot-tips

    Directory of Open Access Journals (Sweden)

    Joanna Makowczyńska

    2011-01-01

    Full Text Available Shoot-tip multiplication of the medicinal species - Plantago asiatica was carried on MS medium with IAA and BAP or kinetin. Best results in micropropagation were achieved by adding 0.1 mg/dm3 IAA and 1 mg/dm3 BAP. After 6 weeks shoots were transferred to MS medium for rooting. The resulting plantlets were transferred after 8 weeks into pots and after a period of adaptation into the ground (field culture. The species Plantago asiatica was propagated in vitro by shoot-tip multiplication for the first time.

  12. Direct calculation of wind turbine tip loss

    DEFF Research Database (Denmark)

    Wood, D.H.; Okulov, Valery; Bhattacharjee, D.

    2016-01-01

    The usual method to account for a finite number of blades in blade element calculations of wind turbine performance is through a tip loss factor. Most analyses use the tip loss approximation due to Prandtl which is easily and cheaply calculated but is known to be inaccurate at low tip speed ratio....... We develop three methods for the direct calculation of the tip loss. The first is the computationally expensive calculation of the velocities induced by the helicoidal wake which requires the evaluation of infinite sums of products of Bessel functions. The second uses the asymptotic evaluation...... of those sums by Kawada. The third uses the approximation due to Okulov which avoids the sums altogether. These methods are compared to the tip loss determined independently and exactly for an ideal three-bladed rotor at tip speed ratios between zero and 15. Kawada's asymptotic approximation and Okulov...

  13. THE INDUCTION OF MICRONUCLEUS UNDER THE INFLUENCE OF ACETAMIPIRID INSECTICIDE ON THE GOLDFISH (CARASSIUS AURATUS AFTER THE TIME TREATMENT OF 24 AND 72 HOURS

    Directory of Open Access Journals (Sweden)

    Smajl Rizani

    2012-06-01

    Full Text Available As a result of environmental, pollution by mutagen substances are created micronucleus, which are genetically defects, which may cause mutation and cancerous diseases. Based in this fact, we have attempted to do a research, which will prove that genetically damages are as result of environment pollution. Our research is based in Micronucleus-test method, according to Schmid. This method is used to be observed micronucleus, as mentioned above are created as result of environment pollution in blood of living organism. As we expected, during the research with this method, we have faced in genetically damage as aftermath of our environment pollution for research. For the research we have decided fish (goldfish, whereas environment pollution is created referring to our needs about research. The result is astonishing. As higher is level of pollution the higher will be the number of micronucleus, more precisely number of genetically damages. We have used 50 fish for our research diffused in five aquariums, distinguished by dose and day of treatment with insecticide. As our environmental pollutant for research we used acetamipirid insecticide in goldfish. The research has resulted what has proved by Schmid with Micronucleus-Test method, which proved the presence of genetic damages harmonized with the amount of pollution. Our research opens the way for safe research in environment polluting to see real situation on the ground and the ability to make managerial policies to prevent pollution, moreover to prevent many diseases caused by such pollution.

  14. Evaluation of in vivo genotoxicity by thioacetamide in a 28-day repeated-dose liver micronucleus assay using male young adult rats.

    Science.gov (United States)

    Sui, Hajime; Matsumoto, Hirotaka; Wako, Yumi; Kawasako, Kazufumi

    2015-03-01

    The repeated-dose liver micronucleus (RDLMN) assay has the potential to detect liver carcinogens and can be integrated into general toxicological studies. In this study, thioacetamide (TAA) was tested in 14- and 28-day RDLMN assays to assess the performance of the assay. The test substance, TAA, was administered orally to 6-week-old male Crl:CD (SD) rats once daily for 14 or 28 days at a dosage of 5, 10 or 20mg/kg/day. Hepatocytes were collected approximately 24h after the last TAA administration, and the incidence of micronuclei was assessed. In this study, bone marrow micronucleus assays were also conducted in the same animals. The 14- and 28-day RDLMN assays indicated that none of the TAA dosages significantly increased the proportion of micronucleated hepatocytes. Bone marrow micronucleus assays with TAA also provided negative results. It is known that TAA is a liver carcinogen in mice and rats. In the previous genotoxic studies, the Ames test and the chromosomal aberration test using CHL/IU cells have yielded negative results [1-4]. The liver micronucleus assay using young adult rats singly dosed with TAA (75 and 150mg/kg) also produced negative results [5]. TAA gave positive results only in the mouse bone marrow micronucleus assays [6,7].

  15. Tip Clearance Flows in Turbine Cascades

    Institute of Scientific and Technical Information of China (English)

    Li Wei; Qiao Weiyang; Sun Dawei

    2008-01-01

    This article describes the effects of some factors on the tip clearance flow in axial linear turbine cascades.The measurements of the total pressure loss coefficient are made at the cascade outlets by using a five-hole probe at exit Mach numbers of 0.10,0.14 and 0.19.At each exit Mach number,experiments axe performed at the tip clearance heights of 1.0%,1.5%,2.0%,2.5% and 3.0% of the blade height.The effects of the non-uniform tip clearance height of each blade in the pitchwise direction are also studied.The results show that at a given tip clearance height,generally,total pressure loss rises with exit Mach numbers proportionally.At a fixed exit Mach number,the total pressure loss augments nearly proportionally as the tip clearance height increases.The increased tip clearance heights in the tip regions of two adjacent blades are to be blame for the larger clearance loss of the center blade.Compared to the effects of the tip clearance height,the effects of the exit Mach number and the pitchwise variation of the tip clearance height on the cascade total pressure loss are so less significant to be omitted.

  16. Tip-modulation scanned gate microscopy.

    Science.gov (United States)

    Wilson, Neil R; Cobden, David H

    2008-08-01

    We introduce a technique that improves the sensitivity and resolution and eliminates the nonlocal background of scanned gate microscopy (SGM). In conventional SGM, a voltage bias is applied to the atomic force microscope tip and the sample conductance is measured as the tip is scanned. In the new technique, which we call tip-modulation SGM (tmSGM), the biased tip is oscillated and the induced oscillation of the sample conductance is measured. Applied to single-walled carbon nanotube network devices, tmSGM gives sharp, low-noise and background-free images.

  17. More Time Management Tips for Busy People

    Science.gov (United States)

    2014-10-01

    OCT 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE More Time Management Tips for Busy People 5a. CONTRACT...50 More Time Management Tips for Busy People Roy Wood, Ph.D.   Wood is the dean of the Defense Systems Management College at the Defense Acquisition...Management Tips for Those Who Don’t Have the Time” (Defense AT&L, November–December 2013, p. 58), that of-fered some time-saving tips for busy people

  18. [Endodontic surgery (apicoectomy)--success rate of more than 90% using dental operating microscope and ultrasonic tips].

    Science.gov (United States)

    Zesis, A; Lin, S; Fuss, Z

    2005-01-01

    The main cause of root canal treatment failure is presence of bacteria in the root canal. Surgical endodontic retreatment is indicated as a valuable treatment choice for failed endodontic treatment. The aim of the article is to describe the advantages of a new technique for apicoectomy using dental operating microscope and ultrasonic tips in comparison to the traditional technique. Precise root end resection with minimal or no bevel and accurate preparation of the root end cavity to the depth of 3-4 mm allows minimal bone removal and reduces procedural accidents such as perforation of the lingual canal wall. Zink oxide eugenol based materials allow sealing of the retrograde preparation adequately to prevent bacteria and toxins to penetrate the periradicular tissues. Literature review demonstrates success rate to above 90% when employing dental operating microscope and ultrasonic tips for retrograde cavity preparation.

  19. Proteins among the polysaccharides: a new perspective on root cap slime.

    Science.gov (United States)

    Wen, Fushi; Curlango-Rivera, Gilberto; Hawes, Martha C

    2007-09-01

    Charles Darwin recognized the power of the root cap as a model for plant signalling and behavior, and used it to explore the ways plants sense and respond to diverse stimuli. Over ensuing decades, various groups have reported tantalizing clues regarding the role of a complex extracellular matrix that ensheaths the tip region housing the apical and root cap meristems. In the course of characterizing root tip resistance to infection and injury and the role border cells play in this phenomenon, we confirmed and extended early- and mid-20(th) century studies reporting enzyme activities secreted from the root cap. Multidimensional protein analysis revealed, in fact, that >100 proteins are actively synthesized and secreted from the root cap and border cells. This 'root cap secretome' appears to be a critical component of root tip resistance to infection. We have developed a microscopic assay to quantify the protein-based extracellular response to dynamic changes in environmental conditions including hydroponic culture, and present the results here. This tool provides a simple, direct measure that can be used to explore the ways border cells may function in the manner of white blood cells to trap, immobilize and neutralize threats to the growing root tip.

  20. Evaluation of a repeated dose liver micronucleus assay in rats treated with two genotoxic hepatocarcinogens, dimethylnitrosamine and 2-acetylaminofluorene: the possibility of integrating micronucleus tests with multiple tissues into a repeated dose general toxicity study.

    Science.gov (United States)

    Takashima, Rie; Takasawa, Hironao; Kawasako, Kazufumi; Ohyama, Wakako; Okada, Emiko; Narumi, Kazunori; Fujiishi, Yohei; Wako, Yumi; Yasunaga, Katsuaki; Hattori, Akiko; Kawabata, Masayoshi; Nakadate, Kiyoko; Nakagawa, Munehiro; Hamada, Shuichi

    2015-03-01

    As part of a collaborative study by the Collaborative Study Group for Micronucleus Test (CSGMT) of the Mammalian Mutagenicity Study Group (MMS) in the Japanese Environmental Mutagen Society (JEMS), the present study evaluated the effectiveness of the repeated dose liver micronucleus (RDLMN) assay. Two genotoxic hepatocarcinogens, dimethylnitrosamine (DMN) and 2-acetylaminofluorene (2-AAF), were administered orally to male rats (6 weeks old at the initial dosing) once daily for 14 and 28 days to evaluate the micronucleus (MN) inducibility in the liver. In addition, these chemicals were evaluated for MN inducibility in the bone marrow (BM) and gastrointestinal (GI) tract, i.e. glandular stomach and colon of the same animals used in the RDLMN assay. As a result, both chemicals produced positive results in the liver, although a weak positive response was given by 2-AAF. DMN gave negative results in the tissues other than the liver. 2-AAF produced positive responses in the BM and glandular stomach, and a prominent response was particularly observed in the glandular stomach, which is directly exposed to the test chemicals by gavage. The present results suggest that the RDLMN assay is a useful method for detecting genotoxic hepatocarcinogens, and that it is especially effective for evaluating test chemicals, such as DMN, undetectable by the BM and GI tract MN assay. Moreover, the results in this investigation indicate that the use of multiple tissues in the study integrating the MN tests is more effective than using a single tissue, for detection of the MN induction produced by chemical exposure to rats, and helps to determine the characteristics of the test chemicals.