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1.
[目的]研究稻壳为模板和硅源合成Ni-TiO2-SiO2对龙胆紫水溶液的吸附性能。[方法]以稻壳为原料合成可再生的染料吸附剂Ni-TiO2-SiO2,研究Ni-TiO2-SiO2对龙胆紫染料的吸附行为。[结果]吸附1 h后Ni-TiO2-SiO2对龙胆紫的吸附率可达90%左右;浓度为25 mg/L的100 ml龙胆紫染料水溶液中,当染料溶液的pH=8、吸附剂用量为0.07 g时,Ni-TiO2-SiO2的吸附效果最好。更重要的是Ni-TiO2-SiO2作为吸附剂可重复使用,并不会因为泄露造成二次污染。[结论]该研究为实际工程应用提供依据。 相似文献
2.
Destruction of Trypanosoma cruzi by Natural killer cells 总被引：16，自引：0，他引：16
Mice infected with trypanosoma cruzi or stimulated with poly(inosinic.cytodylic acid) were found to possess splenic and peritoneal exudate cells with enhanced cytotoxic activity against epimastigote and trypomastigote forms of Trypanosoma cruzi. By use of specific alloantiserums it was determined that the effector cells responsible for this cytotoxic activity were typical natural killer cells. 相似文献
3.
E E Montamat C Burgos N M Gerez de Burgos L E Rovai A Blanco E L Segura 《Science (New York, N.Y.)》1982,218(4569):288-289
Gossypol, a phenolic compound isolated from the cotton plant, is a powerful inhibitor of nicotinamide adenine dinucleotide-linked enzymes (alpha-hydroxyacid dehydrogenase and malate dehydrogenase) of Trypanosoma cruzi, the parasite that causes Chagas' disease. Parasites at the epimastigote stage that were incubated for 5 minutes with 100 micromolar gossypol were completely immobilized. Concentrations of gossypol as low as 0.01 micromolar markedly reduced the growth rate of T. cruzi in culture. 相似文献
4.
Trypanosoma cruzi infection inhibited by peptides modeled from a fibronectin cell attachment domain 总被引：10，自引：0，他引：10
M A Ouaissi J Cornette D Afchain A Capron H Gras-Masse A Tartar 《Science (New York, N.Y.)》1986,234(4776):603-607
The mechanism by which Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, becomes attached to mammalian cells is not well understood. Fibronectin is thought to participate in the attachment, and in this study the region of fibronectin that interacts with the surface receptors of T. cruzi trypomastigotes was investigated by testing the binding of the amino acid sequence Arg-Gly-Asp-Ser, corresponding to the cell attachment site of fibronectin to T. cruzi trypomastigotes. Peptides with the sequence Arg-Gly-Asp-Ser, but not Arg-Phe-Asp-Ser, Arg-Phe-Asp-Ser-Ala-Ala-Arg-Phe-Asp, Ser-Lys-Pro, Glu-Ser-Gly, or Ala-Lys-Thr-Lys-Pro, bound to the parasite surface and inhibited cell invasion by the pathogen. Monoclonal antibodies to the cell attachment domain of fibronectin also inhibited cell infection by the parasite. The immunization of BALB/c mice with tetanus toxoid-conjugated peptide induced a significant protection against T. cruzi. The data support the notion that the sequence Arg-Gly-Asp-Ser of cell surface fibronectin acts as a recognition site for attachment of the parasites. 相似文献
5.
苜蓿总黄酮对小鼠脂类代谢及氧自由基的影响 总被引：2，自引：0，他引：2
试验结果显示：灌胃给予苜蓿总黄酮（TFA）的小鼠全血中甘油三酯（TG）和低密度脂蛋白胆固醇（LDL—C）的含量明显降低（P〈0．05）,而高密度脂蛋白胆固醇（HDL—C）含量升高,而且其肝脏和肾脏组织匀浆中过氧化物歧化酶（SOD）的活性显著升高（P〈0．05）,丙二醛（MDA）的含量降低。因此得出结论：TFA具有降血脂、降低低密度脂蛋白胆固醇含量、预防和减轻动脉硬化的作用;同时也具有抑制氧自由基损伤、防止脂质过氧化的作用。 相似文献
6.
Atwood JA Weatherly DB Minning TA Bundy B Cavola C Opperdoes FR Orlando R Tarleton RL 《Science (New York, N.Y.)》2005,309(5733):473-476
To complement the sequencing of the three kinetoplastid genomes reported in this issue, we have undertaken a whole-organism, proteomic analysis of the four life-cycle stages of Trypanosoma cruzi. Peptides mapping to 2784 proteins in 1168 protein groups from the annotated T. cruzi genome were identified across the four life-cycle stages. Protein products were identified from >1000 genes annotated as "hypothetical" in the sequenced genome, including members of a newly defined gene family annotated as mucin-associated surface proteins. The four parasite stages appear to use distinct energy sources, including histidine for stages present in the insect vectors and fatty acids by intracellular amastigotes. 相似文献
7.
8.
A developmentally regulated neuraminidase activity in Trypanosoma cruzi 总被引：18，自引：0，他引：18
M E Pereira 《Science (New York, N.Y.)》1983,219(4591):1444-1446
The human pathogen Trypanosoma cruzi (Y strain) contains a neuraminidase activity that varies widely in the different developmental stages of the parasite. The specific neuraminidase activity of infective trypomastigotes obtained from tissue culture and from the bloodstream of infected mice is 7 to 15 times higher than that of the acellular culture forms. Amastigotes were devoid of enzyme activity. The enzyme has a pH optimum of 6.0 to 6.5. Live trypanosomes released sialic acid from human erythrocytes and plasma glycoproteins. Several sialyl compounds were hydrolyzed by the parasite, but the best substrate was the protein orosomucoid. Erythrocytes from infected mice with T. cruzi parasitemia were agglutinated by peanut lectin and the hemagglutination titer was correlated with the degree of parasitemia. 相似文献
9.
American trypanosomiasis, or Chagas disease, caused by the protozoan parasite Trypanosoma cruzi and transmitted by blood-feeding triatomine bugs, is a chronic, frequently fatal infection that is common in Latin America. Neither adequate drugs nor a vaccine is available. A mathematical model calibrated to detailed household data from three villages in northwest Argentina shows that householders could greatly reduce the risk of human infection by excluding domestic animals, especially infected dogs, from bedrooms; removing potential refuges for bugs from walls and ceilings; and using domestically applied insecticides. Low-cost, locally practicable environmental management combined with intermittent use of insecticides can sustainably control transmission of T. cruzi to humans in rural Argentina and probably elsewhere. 相似文献
10.
通过动物药理试验，发现儿茶素能明显减少兔外伤皮损内Ｄｏｐａ阳性的黑色细胞数，从而减少局部的色素沉着．试验结果表明，儿茶素治疗色素沉着主要是通过调节机体自由基系统，保护ＳＯＤ活性，抑制酪氨酸酶的活性，从而抑制ＬＰＯ的形成，减少含酪氨酸酶的黑素细胞，从而达到减轻色素沉着的效果． 相似文献
11.
El-Sayed NM Myler PJ Bartholomeu DC Nilsson D Aggarwal G Tran AN Ghedin E Worthey EA Delcher AL Blandin G Westenberger SJ Caler E Cerqueira GC Branche C Haas B Anupama A Arner E Aslund L Attipoe P Bontempi E Bringaud F Burton P Cadag E Campbell DA Carrington M Crabtree J Darban H da Silveira JF de Jong P Edwards K Englund PT Fazelina G Feldblyum T Ferella M Frasch AC Gull K Horn D Hou L Huang Y Kindlund E Klingbeil M Kluge S Koo H Lacerda D Levin MJ Lorenzi H Louie T Machado CR McCulloch R 《Science (New York, N.Y.)》2005,309(5733):409-415
Whole-genome sequencing of the protozoan pathogen Trypanosoma cruzi revealed that the diploid genome contains a predicted 22,570 proteins encoded by genes, of which 12,570 represent allelic pairs. Over 50% of the genome consists of repeated sequences, such as retrotransposons and genes for large families of surface molecules, which include trans-sialidases, mucins, gp63s, and a large novel family (>1300 copies) of mucin-associated surface protein (MASP) genes. Analyses of the T. cruzi, T. brucei, and Leishmania major (Tritryp) genomes imply differences from other eukaryotes in DNA repair and initiation of replication and reflect their unusual mitochondrial DNA. Although the Tritryp lack several classes of signaling molecules, their kinomes contain a large and diverse set of protein kinases and phosphatases; their size and diversity imply previously unknown interactions and regulatory processes, which may be targets for intervention. 相似文献
12.
Polyamine metabolism: a potential therapeutic target in trypanosomes 总被引：16，自引：0，他引：16
C J Bacchi H C Nathan S H Hutner P P McCann A Sjoerdsma 《Science (New York, N.Y.)》1980,210(4467):332-334
alpha-Difluoromethylornithine (RMI 71,782), a specific irreversible inhibitor of the first step in polyamine biosynthesis, that is, the formation of putrescine from ornithine by ornithine decarboxylase, cures mice infected with a virulent, rodent-passaged strain of Trypanosoma brucei brucei. This parasite is closely related to the trypanosomes that cause human sleeping sickness. The drug, which is remarkably nontoxic, was effective when administered in drinking water or by intubation. The ability of the compound to inhibit ornithine decarboxylase in vitro was demonstrated by the reduced amounts of putrescine synthesized from tritiated ornithine in Trypanosoma brucei suspensions. These observations direct attention to polyamine metabolism as a target for chemotherapy of parasitic diseases. 相似文献
13.
研究了不同超干度的红花种子自由基和水分状态．结果显示：自由水／束缚水比例随着超干种子内含水量的降低而减小．超干引起内、外种皮自由基急剧增加,而胚中自由基的上升发生在超干种子的老化期间．超干或超干后又经老化的种子在高湿度的环境中经回水处理能使胚中自由基水平急剧下降到相当低的水平．超干轻微地降低种子萌发率和种子活力,但大大地增进了种子抗老化的能力．本文还对超干种子老化过程中,胚中高水平自由基的情况下仍保持高的种子萌发率和种子活力的生理原因进行了讨论． 相似文献
14.
El-Sayed NM Myler PJ Blandin G Berriman M Crabtree J Aggarwal G Caler E Renauld H Worthey EA Hertz-Fowler C Ghedin E Peacock C Bartholomeu DC Haas BJ Tran AN Wortman JR Alsmark UC Angiuoli S Anupama A Badger J Bringaud F Cadag E Carlton JM Cerqueira GC Creasy T Delcher AL Djikeng A Embley TM Hauser C Ivens AC Kummerfeld SK Pereira-Leal JB Nilsson D Peterson J Salzberg SL Shallom J Silva JC Sundaram J Westenberger S White O Melville SE Donelson JE Andersson B Stuart KD Hall N 《Science (New York, N.Y.)》2005,309(5733):404-409
A comparison of gene content and genome architecture of Trypanosoma brucei, Trypanosoma cruzi, and Leishmania major, three related pathogens with different life cycles and disease pathology, revealed a conserved core proteome of about 6200 genes in large syntenic polycistronic gene clusters. Many species-specific genes, especially large surface antigen families, occur at nonsyntenic chromosome-internal and subtelomeric regions. Retroelements, structural RNAs, and gene family expansion are often associated with syntenic discontinuities that-along with gene divergence, acquisition and loss, and rearrangement within the syntenic regions-have shaped the genomes of each parasite. Contrary to recent reports, our analyses reveal no evidence that these species are descended from an ancestor that contained a photosynthetic endosymbiont. 相似文献
15.
Ivens AC Peacock CS Worthey EA Murphy L Aggarwal G Berriman M Sisk E Rajandream MA Adlem E Aert R Anupama A Apostolou Z Attipoe P Bason N Bauser C Beck A Beverley SM Bianchettin G Borzym K Bothe G Bruschi CV Collins M Cadag E Ciarloni L Clayton C Coulson RM Cronin A Cruz AK Davies RM De Gaudenzi J Dobson DE Duesterhoeft A Fazelina G Fosker N Frasch AC Fraser A Fuchs M Gabel C Goble A Goffeau A Harris D Hertz-Fowler C Hilbert H Horn D Huang Y Klages S Knights A Kube M Larke N Litvin L Lord A 《Science (New York, N.Y.)》2005,309(5733):436-442
16.
比较老鼠簕粗多糖(CAP)、老鼠簕酸性多糖B组分(AAPB)和老鼠簕中性多糖(NAP)的体外抗氧化能力。从采自广东省汕头市澄海区的老鼠簕树枝提取老鼠簕多糖,测定多糖的还原力,及其对DPPH自由基、邻苯三酚自氧化体系产生的超氧阴离子自由基(O2-.)和Feton体系产生的羟基自由基(.OH)的清除能力。CAP、AAPB和NAP均具有较强的抗氧化性和良好的还原力,AAPB的抗氧化能力远高于中性多糖NAP。层析纯化后的老鼠簕酸性多糖AAPB清除自由基的效果有明显提高,特别是对羟基自由基。0.2 mg/ml AAPB可以除去80.0%的DPPH自由基,对超氧阴离子的抑制率为66.1%;0.5 mg/ml AAPB对羟基自由基的清除率达到48.5%。老鼠簕酸性多糖AAPB是老鼠簕粗多糖CAP中最重要的抗氧化成分。 相似文献
17.
油菜蕾长与花粉发育时期的关系研究 总被引：3，自引：0，他引：3
本文取1.0-5.0mm的花蕾,用1%龙胆紫染液压片法制片,在光学显微镜下观察花粉发育情况。通过对油菜花粉细胞发育过程的观察,探讨花蕾长度与花粉发育时期的相互关系,以便在进行有关遗传性状改良或其他生物技术研究活动时,可以直接依据花蕾长度,判断花粉发育时期。结果表明：当花蕾1.0-1.5mm长时,花粉基本处于减数分裂时期;花蕾1.6-2.2m长时,为花粉发育的四分体时期;花蕾2.3-3.0mm长时,为花粉发育的单核高峰期;花蕾3.1-3.7mm长时,为花粉发育的双核高峰期;花蕾3.8-5.0mm及以上长时,为花粉发育的成熟期。 相似文献
18.
龙胆草斑枯病由Septoria spp.侵染引起,主要为害叶片,是龙胆草生长过程中危害最严重的病害.目前缺乏对龙胆草抗病性、病害流行规律及防治技术等方面的系统研究.文章通过室内抑菌试验筛选出对该病原菌抑制效果较好的药剂叶病康和代森锰锌.田间药效试验结果表明,硫酸小诺霉素对该病的防治效果较好,在发病后期防治效果达69.2... 相似文献
19.
研究紫红薯糖蛋白的体外抗氧化活性。使用水提醇沉方法、Sevage法除游离蛋白,用DEAE-52纤维素层析及SephadexG-75纯化制备糖蛋白。采用超氧阴离子自由基(O-2.)、羟基自由基(·OH)、1,1-二苯基-2-苯肼自由基(DPPH.)清除率测定法及还原力测定法评价紫红薯糖蛋白体外抗氧化活性。糖蛋白在0～640μg/mL内,均具有明显的抗氧化活性,随着质量浓度的增加活性增强;其中在紫红薯糖蛋白的质量浓度为640μg/mL时,对超氧阴离子自由基(O-2.)清除作用达到69.80%;对羟基自由基(.OH)的清除作用达到73.29%。 相似文献
20.
龙胆草斑枯病发生规律及其防治研究 总被引：8，自引：0，他引：8
龙胆草斑枯病是近几年生产上发生的一种毁灭性病害。作者对该病害的发生规律和防治进行了初步研究。研究结果表明：该病菌是一种高温高湿喜光病菌。高温、高湿、裸露和低密度栽培有利病害的发生和流行。根据病害的发生规律将侵染循环分成五个阶段。只有采取种苗消毒、田园卫生、遮阴栽培和药剂防治等综合防治措施,才能取得理想的防治效果。 相似文献