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71.
通过37℃恒温振荡培养含有Taq DNA聚合酶基因的E.coli菌株,并用IPTG诱导该基因表达获得TaqDNA聚合酶蛋白,利用40%硫酸铵沉淀该蛋白后溶解于storage buffer中.此法获得的Taq DNA聚合酶带负电荷,因此采用阴离子交换柱纯化蛋白.试验结果表明,此法与传统的透析方法相比能快速地去除生物小分子杂质,同时去除透析方法无法除去的杂蛋白;既能保证Taq DNA聚合酶的生物学活性,同时能缩短纯化时间、提高Taq DNA聚合酶的纯度.以土壤微生物DNA、水稻cDNA为模板进行PCR扩增并对扩增产物进行测序,结果显示纯化后的Taq DNA聚合酶具有较高的扩增效率和保真性. 相似文献
72.
采前施用钾肥对菠萝果实贮藏特性的影响 总被引:2,自引:0,他引:2
为提高果实的贮藏品质,以菠萝品种巴厘(Ananas comosus cv.Comtede Paris)为试材,采用滴灌形式,研究施钾(硫酸钾和氯化钾)对果实贮藏期间可溶性固形物、可溶性蛋白、维生素C、可滴定酸和可溶性糖的影响.结果表明:适量增施硫酸钾能提高果实采收时可溶性糖、可溶性蛋白、可滴定酸、维生素C的含量;延缓果实贮藏中后期可溶性固形物、维生素C和可滴定酸含量的下降,提高可溶性蛋白含量.而增施氯化钾则显著减少了采收时果实可溶性固形物含量,并且不影响贮藏期间果实维生素C含量.因此,施900 kg/hm2硫酸钾处理果实贮藏品质更好. 相似文献
73.
Tatiana da Rosa Guimar?es Carlos Guillermo Quiroz Caroline Rigotto Simone Quintana de Oliveira Maria Tereza Rojo de Almeida éverson Miguel Bianco Maria Izabel Goulart Moritz Jo?o Luís Carraro Jorge Alejandro Palermo Gabriela Cabrera Eloir Paulo Schenkel Flávio Henrique Reginatto Cláudia Maria Oliveira Sim?es 《Marine drugs》2013,11(11):4176-4192
The n-butanol fraction (BF) obtained from the crude extract of the marine sponge Petromica citrina, the halistanol-enriched fraction (TSH fraction), and the isolated compounds halistanol sulfate (1) and halistanol sulfate C (2), were evaluated for their inhibitory effects on the replication of the Herpes Simplex Virus type 1 (HSV-1, KOS strain) by the viral plaque number reduction assay. The TSH fraction was the most effective against HSV-1 replication (SI = 15.33), whereas compounds 1 (SI = 2.46) and 2 (SI = 1.95) were less active. The most active fraction and these compounds were also assayed to determine the viral multiplication step(s) upon which they act as well as their potential synergistic effects. The anti-HSV-1 activity detected was mediated by the inhibition of virus attachment and by the penetration into Vero cells, the virucidal effect on virus particles, and by the impairment in levels of ICP27 and gD proteins of HSV-1. In summary, these results suggest that the anti-HSV-1 activity of TSH fraction detected is possibly related to the synergic effects of compounds 1 and 2. 相似文献
74.
Tahereh A. Aghajanzadeh Martin Reich Malcolm J. Hawkesford Meike Burow 《Archives of Agronomy and Soil Science》2019,65(7):945-956
Salinity as a major agricultural problem can affect crop growth and quality. Onion (Allium cepa L.) plant contains a wide variety of sulfur-containing compounds which may be involved in plant protection against salt stress. In the current study, a similar reduction in growth caused by chloride and sulfate salts was observed when onion was exposed to equimolar concentrations of Na+. Also, no difference was observed for shoot/root ratio and dry matter content of roots and shoots. Plants accumulated Na+ and the respective anions (chloride and sulfate) which in turn caused changes in the content of other nutrients. The content of potassium and calcium was decreased more than the other elements by both sodium salts. Sulfate salinity resulted in substantial increase in total sulfur and sulfate content but chloride salinity affected neither the total sulfur nor sulfate content of the roots and shoots, only in onion exposed to 200 mM chloride salt, those of roots and shoots were reduced. Furthermore, the water-soluble non-protein thiol content as well as the content of alliin remained rather unaffected. In conclusion, either salts affected the uptake and distribution of sulfate in onion, but had no or only a minor effect on the plant sulfur metabolism. 相似文献
75.
In this research experiment, two commercial onion cultivars (Allium cepa L., cvs. Dorrcheh and Cebolla Valenciana) were grown in sand culture and exposed to two levels of selenium (Se) (0 and 25?µM) and two levels of sulfate (1 and 3?mM). According to the results obtained, addition of 25?µM Se in combination with 3?mM sulfate was not only effective in significant increase of onion bulb yield, but it significantly increased Se concentration of bulb. By considering the average consumption of onion in central Iran, the daily intake of Se via consumption of Se-biofortified onion is estimated to be 68.4–77.2?µg in spring and summer and 72.6–117.1?µg in fall and winter. These amounts of daily intakes of Se is higher than the sufficient levels of Se recommended by world health organization (WHO) but less than the maximum tolerable level of Se (400?µg Se per day) for human. 相似文献
76.
Gabriela Vargas Jos Verdejo Adrian Rivera Domingo Surez Cristian Youlton Juan L. Celis-Diez Yves Le Bissonnais Elvira A. Dovletyarova Alexander Neaman 《植物养料与土壤学杂志》2019,182(2):159-166
The structural stability of soil is a physical characteristic that affects soil degradation processes. Calcium‐based amendments, such as calcium carbonate, calcium sulfate, and calcium oxide/hydroxide, have been shown to improve the stability of soil aggregates. This study seeks to determine which calcium‐based soil amendments, and at what concentration, are the most efficient in improving aggregate stability of sandy topsoils derived from granitic and metamorphic parent materials, and to analyze the mechanisms involved. In the pot experiment, soils amended with CaCO3, CaCl2, and CaSO4 did not present significant differences in aggregate stability compared to the control or among each other. In contrast, Ca(OH)2 soil amendment brought the greatest stability to the soil aggregates. A dose of 1% Ca(OH)2 significantly increased the stability of soil aggregates. This effect is due to the reaction of Ca(OH)2 with atmospheric CO2 which leads to the formation of CaCO3, a delayed reaction not showed by the other soil amendments tested. Likewise, the greater solubility of Ca(OH)2 compared to CaCO3 exerts a greater aggregation effect on soil. Thus, the mechanism of action of Ca(OH)2 is related to cementation, rather than flocculation. Future studies should be carried out to demonstrate the effectiveness of Ca(OH)2 under field conditions. 相似文献
77.
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79.
Renschler J Tarigo J Neel J Grindem C 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2008,37(1):129-132
9-year-old castrated male Greyhound dog was presented for evaluation of vomiting and lethargy of 1-week duration. On physical examination, the dog was febrile and dehydrated with a tense abdomen and petechial hemorrhages. Clinicopathologic abnormalities included relative polycythemia, mild lymphopenia with reactive lymphocytes, hypoalbuminemia, hypocholesterolemia, hyperbilirubinemia, increased ALP, mild hypokalemia, hyperamylasemia, hyperlipasemia, increased D-dimer concentration, and hyperfibrinogenemia. Cytologic evaluation of peritoneal fluid revealed marked suppurative inflammation with intracellular barium sulfate particles. The day before presentation, the referring veterinarian had administered oral barium sulfate in an upper gastrointestinal contrast study. Radiographs revealed free contrast material in the peritoneal cavity, consistent with gastrointestinal perforation, and leakage of contrast material. Abdominal exploratory surgery revealed a mid-jejunal perforation and a hepatic nodule. Histopathologic diagnosis of the jejunal and liver lesions was T-cell lymphoma. The patient recovered well postoperatively and received chemotherapy for treatment of lymphoma. Most commercial barium sulfate preparations contain relatively uniform, weakly birefringent, pale yellow particles <1 microm in diameter. Because barium sulfate is found occasionally in clinical specimens, cytopathologists should be familiar with its cytologic appearance. 相似文献
80.
试验旨在评估日粮添加不同铜源对肉鸭生长性能、屠宰性能和粪便铜含量的影响。选取1056只1日龄樱桃谷肉鸭,分为硫酸铜组、蛋氨酸螯合铜组2个处理组,每个处理4个重复,每个重复132只。结果显示:在生长性能方面,饲粮中添加不同铜源对肉鸭各阶段日采食量、日增重和出栏体重影响不显著(P>0.05)。全期来看,添加蛋氨酸螯合铜组肉鸭1~38日龄料重比显著改善(P<0.05)。在屠宰性能方面,不同铜源对肉鸭各胴体指标均影响不显著(P>0.05)。蛋氨酸螯合铜组肉鸭粪便中铜含量比硫酸铜组高0.8mg/kg,但差异不显著(P>0.05)。综上,除料重比外,日粮添加不同铜源对肉鸭生长性能、粪铜含量影响无显著差异。 相似文献