No abstract

We expressed the heat-labile enterotoxin B (LTB) subunit from enterotoxigenic Escherichia coli and the cholera toxin B (CTB) subunit from Vibrio cholerae under the control of the rice (Oryza sativa) globulin (Glb) promoter. Binding of recombinant LTB and CTB proteins was confirmed based on GM1-ganglioside binding enzyme-linked immunosorbent assays (GM1-ELISA). Real-time PCR of three generations (T3, T4, and T5) in homozygous lines (LCI-11) showed single copies of LTB, CTB, bar and Tnos. LTB and CTB proteins in rice transgenic lines were detected by Western blot analysis. Immunogenicity trials of rice-derived CTB and LTB antigens were evaluated through oral and intraperitoneal administration in mice, respectively. The results revealed that LTB- and CTB-specific IgG levels were enhanced in the sera of intraperitoneally immunized mice. Similarly, the toxin-neutralizing activity of CTB and LTB in serum of orally immunized mice was associated with elevated levels of both IgG and IgA. The results of the present study suggest that the combined expression of CTB and LTB proteins can be utilized to produce vaccines against enterotoxigenic strains of Escherichia coli and Vibrio cholera, for the prevention of diarrhea.

ABSTRACT. Forty schools having natural turf playgrounds were investigated by on-spot investigation and oral interviews with relevant school officials to find out basic information on turfgrass management practices of school playgrounds in Gyeonggi province. Average area of playground was 3,890 m 2 per school and 12 m 2 per student. Ninety five percent of turf playgrounds were managed by school staff and ninety percent of schools spent less than 5 million won per year for turf management. The difficulties in turfgrass management were considered as a major challenge for the schools, followed by turfgrass management cost. Among the management practices, school officials pointed out weed management as the most difficult work, followed by irrigation. The average number of fertilization and mowing was 2 and 6 times per year, respectively. About the half of playgrounds were irrigated only when there was wilting symptom. Zoysiagrass was the most popular choice for the school playgrounds and only three school playgrounds were established with pop-up irrigation system. Fourteen school playgrounds had good turf quality but the rest of school playgrounds had inadequate turf quality requiring minor or full renovation.

Having a variety of flower colors makes Schlumbergera truncata more valuable as an ornamental. S. truncata quality is mainly determined based on the number of phylloclades and flowering at the apical phylloclades. Cytokinins have been shown to promote branching and flowering in Cactaceae. This study was carried out to investigate the effects of growth regulators on the plant growth and flowering of four cultivars of S. truncata: 'Orange Candle', 'Pink Dew', 'Red Roman', and 'Snow Queen'. Foliar treatments of benzylamino purine (BA) or both a mixture of BA and gibberellic acid (GA 3 ) were applied (100 -200 mg•L -1 ) when plants reached the three-phylloclade stage under a long-day photoperiod. All plants treated with BA alone or the mixture of BA and GA 3 produced more phylloclades and branches than the control. Application of BA significantly produced more phylloclades and branches than BA in combination with GA 3 . However, BA application shortened the length of phylloclades, while adding GA 3 to BA promoted the elongation of phylloclades but delayed flowering. During the second trial, only BA was applied at 0 to 100 mg•L -1 to the plants at the two-phylloclade stage under a long-day photoperiod. The number of phylloclades increased by 19.8 -33.0% without shortening the length of phylloclades when BA was applied at 50 or 75 mg•L -1 concentration. The number of flower buds increased by 100 to 190% under short days when BA at 100 mg•L -1 was applied on 'Orange Candle' and 'Red Roman', while BA application at 150 -200 mg•L -1 increased only from 33.0 to 41.7% in 'Pink Dew' and 'Snow Queen'. The number of flower buds increased with the higher concentration of BA, but the number of days to flower decreased and the length of the flowers shortened. In conclusion, Only BA application appears to be more effective for increasing the number of phylloclades and flower buds in S. truncata.