Control Effects of Bacillus subtilis DJ-6 and Pyraclostrobin Alone and in Combination Against Fusarium oxysporum

[Objective] This study was conducted to screen a synergistic biological fungicide complex to control Fusarium wilt, reducing the use of chemical pesticides. [Method] The inhibitory effects of Bacil us subtilis DJ-6 and pyraclostrobin alone or in combination at five ratios against Fusarium oxysporum were detected by mea-suring mycelium growth rate in laboratory tests. The growth promotion and disease control effect of combined or single use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000, 1∶2 000 and 1∶3 000 dilutions were detected in field trials. [Result] The EC50 values of combined use of B. subtilis DJ-6 and pyra-clostrobin at ratios of 1∶1, 1∶2, 1∶3, 1∶4 and 1∶5 against F. oxysporum were 5.311 5, 4.008 6, 3.570 6, 3.350 9 and 3.218 9 μg/ml, with the synergistic ratios （SR） of 2.28, 1.77, 1.53, 1.64, 1.11, among which the synergetic effect at 1∶1 was the best. The fungicidal activity of pyraclostrobin was greater than that of B. subtilis DJ-6 in laboratory tests. Field trials revealed that al the 1∶1 000, 1∶2 000 and 1∶3 000 dilu-tions of 20% pyraclostrobin·2×1011 cfu/g B. subtilis DJ-6 WP in combination, 1∶1 000 dilution of 1 ×1012 cfu/g B. subtilis DJ-6 WP and 1∶2 000 dilution of 250 g/L pyra-clostrobin EC promoted the growth of strawberry by increasing plant height, leaf petiole, leaf blade area and stem diameter. Among them, the treatments with 1∶1 000 and 1∶2 000 of 20% pyraclostrobin · 2×1011 cfu/g B. subtilis DJ-6 WP in combina-tion had better effects than other treatments. The control effects of al the treat-ments were measured 30 and 80 d after fungicide application. The control effects of 1∶1 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combina-tion were up to 100% and 93.11%, which were higher than those in al other treat-ments. The second highest control effects were found in the treatment with 1∶ 2 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination, they were 92.49% and 86.49%, higher than those in other treatments except the 1∶1 000 dilution of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 in combination. The control effects of 1∶3 000 dilution of 20% pyraclostrobin and 2×1011 cfu/g B. subtilis DJ-6 in combination were 82.61% and 72.42%, higher than those in treatment with 1∶1 000 dilution of 1×1012 cfu/g B. subtilis DJ-6 WP, but lower than those in treat-ment with 1∶2 000 dilution of 25% pyraclostrobin EC. [Conclusion] Al the results re-vealed that the combination use of 20% pyraclostrobin and 2 ×1011 cfu/g B. subtilis DJ-6 WP at 1∶1 000 to 1∶2 000 dilution had better control effect against strawberry Fusarium wilt.

哌拉西林与氧氟沙星联合抗菌活性的研究(摘要)

目前对于严重的难治性感染性疾病常采用抗菌药物联合治疗。本文根据棋盘法设计,应用微量稀释法研究了酰脲类青霉素哌拉西林(Piperacillin,PIP)与氟喹诺酮类药物氧氟沙星(Ofloxacin,OFLX)的体外联合抗菌活性。

Selective targeted adsorption and inactivation of antibiotic-resistant bacteria by Cr-loaded mixed metal oxides

Herein we provide a novel high-efficiency nanocomposite for bacterial capture based on mixed metal oxides(MMOs)with deleterious chromium properties.With both the layer structure of layered double hydroxides(LDHs)and the magnetic properties of Fe,MMOs enrich the location of ionic forms on the surface,providing a good carrier for adsorption of the heavy metal Cr(VI).The capacity for adsorption of Cr(VI)by MMOs can be as high as 98.80 mg/g.The prepared Cr(VI)-MMOs achieved extremely expeditious location of gram-negative antibiotic-resistant E.coliNDM-1 by identifying lipid bilayers.Cr-MMOs with a Cr loading of 19.70 mg/g had the best bactericidal effect,and the concentration of E.coliNDM-1 was decreased from~10^(8) to~10^(3) CFU/mL after 30 min of reaction.The binding of nitrogen and phosphorus hydrophilic groups to chromate generated realistic models for density functional theory(DFT)calculations.The specific selectivity of MMOs toward bacterial cells was improved by taking Cr(VI)as a transferable medium,thereby enhancing the antibacterial activity of Cr-MMOs.Under the combined action of chemical and physical reactions,Cr(VI)-MMOs achieved high capacity for inactivation of bacteria.Moreover,the metallic elements ratio in Cr-MMOs remained stable in their initial valence states after inactivation.This guaranteed high removal efficiency for both heavy metals and bacteria,allowing recycling of the adsorbent in practical applications.