Isolation and Characterization of Bacillus Strain as a Potential Biocontrol Agent

Abstract

In this study, to retain a stable bacterial inoculant, Bacillus strains showing antifungal activity were screened. The improved production, antifungal mechanism, and stability of the antifungal metabolite by a selected strain, AF4, a potent antagonist against phytopathogenic Botrytis cinerea, were also investigated. The AF4 strain was isolated from rhizospheric soil of hot pepper and identified as Bacillus subtilis by phenotypic characters and 16S rRNA gene analysis. Strain AF4 did not produce antifungal activity in the absence of a nitrogen source and produced antifungal activity at a broad range of temperatures (25-40°C) and pH (7-10). Optimal carbon and nitrogen sources for the production of antifungal activity were glycerol and casein, respectively. Under improved conditions, the maximum antifungal activity was 140±3 AU/ml, which was higher than in the basal medium. Photomicrographs of strain AF4-treated B. cinerea showed morphological abnormalities of fungal mycelia, demonstrating the role of the antifungal metabolite. The B. subtilis AF4 culture exhibited broad antifungal activity against several phytopathogenic fungi. The antifungal activity was heat-, pH-, solvent-, and protease-stable, indicating its nonproteinous nature. These results suggest that B. subtilis AF4 is a potential candidate for the control of phytopathogenic fungi-derived plant diseases.

Factors affecting vegetable preference in adolescents: stages of change and social cognitive theory

“…Food choices or preferences in childhood or adolescence can continue into adulthood; the food choices one makes in adolescence directly affects those in adulthood, when one becomes independent and responsible for managing their own diet [ 9 10 ]. Thus, from the long-term perspective of improving national health and quality of life, it has become clear that adolescents require nutrition education, not only from educational experts but also from nutritionists.…”

Enhanced Degradation of Residual Cadusafos in Soils by the Microbial Agent of Cadusafos-degrading Sphingobium sp. Cam5-1

“…Key words: Biodegradation, Cadusafos, Microbial agent, Soil 서 론 현재 농업에서 화학 농약의 사용은 작물 생산량 증대 그리 고 다양한 병원체로부터 발생하는 식물병 방제를 위한 가장 효과적인 방법이다 [1]. 그러나 화학 농약은 의도적으로 생명체 를 죽이기 위해 만들어진 독성이 있는 유해화학물질로써 과다 사용 시 토양 잔류로 인해 식물, 동물 그리고 사람에게 전이되 어 부정적 영향을 주는 것으로 알려져 있다 [2,3].…”