Biocontrol Activity of Volatile-Producing Bacillus megaterium and Pseudomonas protegens against Aspergillus flavus and Aflatoxin Production on Stored Rice Grains

In our previous study, three bacterial strains, Bacillus megaterium KU143, Microbacterium testaceum KU313, and Pseudomonas protegens AS15, were selected as effective biocontrol agents against Aspergillus flavus on stored rice grains. In this study, we evaluated the inhibitory effects of the volatiles produced by the strains on A. flavus growth and aflatoxin production on stored rice grains. The three strains significantly reduced mycelial growth of A. flavus in dual-culture assays compared with the negative control strain, Sphingomonas aquatilis KU408, and an untreated control. Of these tested strains, volatiles produced by B. megaterium KU143 and P. protegens AS15 markedly inhibited mycelial growth, sporulation, and conidial germination of A. flavus on agar medium and suppressed the fungal populations in rice grains. Moreover, volatiles produced by these two strains significantly reduced aflatoxin production in the rice grains by A. flavus. To our knowledge, this is the first report of the suppression of A. flavus aflatoxin production in rice grains using B. megaterium and P. protegens volatiles.

Populations of Fungi and Bacteria Associated with Samples of Stored Rice in Korea

Stored rice was collected from rice processing complexes of National Agricultural Cooperative Federation of 11 regions in Korea to evaluate the occurrence of fungi and bacteria and to identify the predominant fungi and bacteria to the genus levels. Most rice samples generally produced the higher levels of fungi and bacteria than white rice. The occurrence of fungi and bacteria varied in various locations of Korea. Among fungi observed, Aspergillus spp. and Penicillium spp. were dominant in the samples and Aspergillus spp. were observed more frequently than Penicillium spp. Predominant bacteria from rice and white rice samples tentatively belonged to the Genus Bacillus, Pectobacterium, Pantoea, and Microbacterium according to BIOLOG and FAME analyses. The results of this study showed that rice in Korea was contaminated in a relatively high level by two dominant storage fungi such as Aspergillus spp. and Penicillium spp. In addition, occurrence of mycotoxins in rice by the fungi could be possible and thus it is necessary to control the storage fungi.

Validity and Reliability of Korean Version of International Physical Activity Questionnaire (IPAQ) Short Form

Background: This study was performed to evaluate the reliability and the validity of the Korean version of IPAQ short form. Method: Sixty-nine volunteer adults completed the questionnaires twice at 1 week interval, and the second one was compared to the results of Actical(R) in order to test validity. Results: The Korean version of IPAQ was accepted as a proper one by the IPAQ developers. Spearman Rho coefficients and Kappa values of test-retest reliability were 0.427~0.646 (median 0.542) and 0.365~0.620 (median 0.471), respectively. The Kappa values were above 0.4 in 5 out of 7 questionnaires. The more physically active by the short form questionnaire, the higher the measured value of the Actical(R) (P=0.039). Spearman Rho coefficient was 0.267 for the correlation between the results of the questionnaire and measured values by Actical(R). Conclusion: The reliability and the validity of the IPAQ short form were proven. Follow-up studies are needed.