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991.
992.
假单胞杆菌B301对稻瘟病菌的拮抗性 总被引:4,自引:0,他引:4
B301是一株分离自空气中的假单胞杆菌(Pseudomonas sp.)。室内测定表明,它能抑制稻瘟病菌的分生孢子萌发和菌丝生长。病菌分生孢子在B301发酵液的2倍稀释液中完全不能萌发,40倍稀释液中的萌发率为35.58%,比对照下降59.4%。B301发酵液稀释140倍时,对病菌菌丝生长的抑制率为52.1%,其抑制菌丝生长的最大稀释度为4480倍。B301发酵液中的抗菌物质具有较强的耐热性,在80℃下,60min仍保持原有活性,但当温度上升到100℃后则不稳定,10min内活性显著下降,80min后完全失活。田间防治试验表明,B301发酵液防治稻瘟病的效果为45%左右,与对照药剂20%三环唑可湿性粉剂500倍液防效相当。此外,B301还能有效抑制棉花炭疽病菌和玉米小斑病菌的生长。 相似文献
993.
Kevin P. Byrne Karen L. Campbell Carol A. Davis David J. Schaeffer & Fred H. Troutt 《Veterinary dermatology》2000,11(2):123-131
Dietary n-3 polyunsaturated fatty acids are widely used for amelioration of inflammatory skin disease in dogs. In this study, a diet containing two different sources of n-3 polyunsaturated fatty acid–triglyceride (from menhaden oil) and concentrated ethyl esters–was fed to one group of six purpose-bred dogs, while an isocaloric isonitrogenous diet with corn oil (n-6 polyunsaturated fatty acids) was fed to another group of eight purpose-bred dogs for six weeks. Peripheral blood neutrophils, isolated at week–1 (baseline), week 2 and week 6, were stimulated with calcium ionophore A23187 and the amount of leukotriene B4 produced was determined via reversed-phase high performance liquid chromatography. Analysis of variance of log-transformed data revealed a significant effect for diet ( P = 0.005) at six weeks, with dogs fed the high n-3 polyunsaturated fatty acid diet having significantly less mean ex vivo neutrophil leukotriene B4 production than dogs fed the high n-6 polyunsaturated fatty acid diet. Further studies on the clinical usefulness of n-3 polyunsaturated fatty acid ethyl esters are warranted. 相似文献
994.
995.
996.
研究将百日咳杆菌用B-G培养基活化后再在改良的S-S培养基上液体培养,用CTAB-NaCl法提取百日咳杆菌的基因组DNA.经PCR扩增出胰岛激活蛋白 B聚体的四个亚基基因,分别将其克隆于pGEX-6p-1载体上,并探讨了在大肠杆菌BL21(DE3)中可溶性表达IAP B聚体各亚基的可能性.通过控制诱导表达温度,S2,S3均可以实现可溶表达,以GST亲和层析得到的S2终产物0.4 mg/L培养物, S3为0.6 mg/L培养物.S4表达虽是可溶性的,但由于融合蛋白的等电点近于7,多步纯化易损失.S5的表达量太低,有待进一步分析. 相似文献
997.
A new 2-arylbenzofuran, sanggenofuran B (3',5'-dihydroxy-6-methoxy-4'-prenyl-2-arylbenzofuran), from the root bark of Chinese Morus cathayana is reported. 相似文献
998.
Plant-derived natural products exhibiting activity against formosan subterranean termites (Coptotermes formosanus) 总被引:1,自引:0,他引:1
The Formosan subterranean termite, Coptotermes formosanus Shiraki, is among the most devastating termite pests. Natural products derived from plant extracts were tested in a discovery programme for effective, environmentally friendly termite control agents. Among the natural products tested, vulgarone B (isolated from Artemisia douglasiana Besser), apiol (isolated from Ligusticum hultenii (Fern.) Calder & Taylor) and cnicin (isolated from Centaurea maculosa Lam.) exhibited significantly higher mortalities than in untreated controls in laboratory bioassay. These compounds are present at high levels in their respective plant sources and also possess other biological activities such as phytotoxic and antifungal properties. 相似文献
999.
1000.
IL-1β expression is increased in response to P. aeruginosa infection, but the responsible proteins have not been clearly elucidated. Here, we demonstrate for the first time that IL-1β expression is induced in response to the heat shock protein 70-like protein DnaK. Treatment with recombinant DnaK (rDnaK) increased IL-1β expression in a dose- and time-dependent manner, and the release of mature IL-1β in response to rDnaK was detected to an extent similar to that stimulated by the well-known agonists, lipopolysaccharide and nigericin. rDnaK-mediated IL-1β expression was driven by the NF-κB signaling pathway. In addition, expression was controlled by the JNK signaling pathway, although these two signaling cascades act independently upon rDnaK stimulation. Finally, rDnaK-induced IL-1β expression was initiated via the action of TLR4. Taken together, the data reveal that P. aeruginosa-derived DnaK induces expression of IL-1β via TLR4-dependent activation of the NF-κB and JNK signaling pathways. 相似文献