Screening, identification and antagonistic effect evaluation of biocontrol strains to Asarum leaf blight / 中国中药杂志

Leaf blight is the main disease of Asarum. At present, chemical treatment is main measure for disease control, and there is no report on biological control. In order to achieve the biological control of Asarum leaf blight, the biocontrol strains with antagonistic effect on Asarum leaf blight were screened. The rhizosphere bacteria of healthy Asarum plants were isolated by soil dilution method, and the isolated strains were screened by the methods of antagonistic antifungal and fermentation liquid antifungal, then the strains were identified and the control effect in vivo was determined. Abiocontrol bacterial strains S2-31 which with high antagonism to leaf blight was obtained from more than 100 isolated strains. The inhibitory rates of antagonistic antifungal and fermentation liquid antifungal reached 92.47% and 60.56%, respectively. It was identified by morphology and 16 S rDNA sequence analysis, and the strain was identified as Brevibacillus laterosporus. The results of indoor potted experiment showed that the control effect was 79.87%, 71.44% and 66.82% on the 3 rd, 5 th and 7 th day after inoculation, respectively, which indicated that S2-31 could reduce the disease index and control the development of Asarum leaf blight.

Identification and Screening of Broad-spectrum Antibiotics-producing Strains / 微生物学通报

60 strains which have antimicrobial activity had been isolated from nutritious soil in China in the study.We have further selected 1 strain which product broad-spectrum antibiotics using agar well-diffusion method.The strain was identified Brevibacillus laterosporus after physiological biochemical characteristic experiments,sequencing of 16S rDNA and cluster analysis,named S62-9.

Optimization of an Antimicrobial Peptide R-1 Production by Brevibacillus laterosporus Lh-1 / 微生物学通报

To improve and optimize marine antimicrobial peptide R-1 production by a newly isolated Brevibacillus laterosporus Lh-1, Plackett-Burman (PB) design and response surface methodology (RSM) using central composite design was adopted in culture conditions. MINITAB 15.0 was used for planning the experiments, data analysis, contour diagrams and response optimizations. In this study, PB design was undertaken to evaluate the effects of the fifteen factors. By the statistical regression analysis, the significant factors affecting the novel antimicrobial peptide R-1 in submerged fermentation by Br. laterosporus Lh-1 were determined as follows: glucose, peptone and CaCl2. Then a RSM was used to optimize the above critical internal factors, and the optical concentration of the variables were deter-mined as: 15.72 g/L glucose, 6.01 g/L peptone and 3.29 g/L CaCl2. The content of R-1 was increased from 82.15 kU/mL to 116.27 kU/mL.