A case of Meropenem as a novel antibacterial agent to suppress and eliminate Agrobacterium tumefaciens in the Agrobacterium-mediated transformation of orchid protocorm-like bodies （PLBs） has been reported in this ar...A case of Meropenem as a novel antibacterial agent to suppress and eliminate Agrobacterium tumefaciens in the Agrobacterium-mediated transformation of orchid protocorm-like bodies （PLBs） has been reported in this article. The in vitro activities of meropenem and four comparator antibacterial agents against three Agrobacterium tumefaciens strains, LBA4404, EHA101, and GV3101, were assessed. In addition, the effect of meropenem on the growth of Dendrobium phalaenopsis PLBs was determined. Compared with other commonly used antibiotics （including ampicillin, carbenicillin, cefotaxime, and cefoperazone）, meropenem showed the highest activity in suppressing all tested A. tumefaciens strains （minimum inhibitory concentration [MIC] 〈 0.5 mg L^-1, which is equal to minimum bactericidal concentration [MBC]）. Meropenem, at all tested concentrations, except for 10 mg L^-1 concentration, had little negative effect on the growth of orchid tissues. The A. tumefaciens strain EHA101 in genetic transformation with vector plG121Hm in infected PLBs of the orchid was visually undetectable after a two-month subculture in 1/2 MS medium with 50 mg L^-1 meropenem and 25 mg L^-1 hygromacin. The expression and incorporation of the transgenes were confirmed by GUS histochemical assay and PCR analysis. Meropenem may be an alternative antibiotic for the effective suppression of A. tumefaciens in genetic transformation.展开更多
Gliadin, the major storage protein in endosperm, affects grain quality in spring wheat by its content and composition. Eighteen cultivars differing in HMW-GS were used in the study to approach the accumulation pattern...Gliadin, the major storage protein in endosperm, affects grain quality in spring wheat by its content and composition. Eighteen cultivars differing in HMW-GS were used in the study to approach the accumulation pattern of gliadin fractions α, β, γ, ω and regulation of three kinds of nitrogen source. The results showed that the content of gliadin in grains increased gradually along with the process of grain-filling, but the accumulation intensity and final content differed evidently among cultivars with different HMW-GS composition. Of all the subunit types used here, cultivars with subunits 7＋9 and 2＋12 had smaller accumulation intensity and lower final content. During grain-filling, 4 gliadin fractions had the same increase trend, but differed in accumulation course. The dynamic trends of gliadin accumulation were similar in different nitrogen treatments whose effects on initial amount, accumulation intensity and final level of accumulation varied with cultivars. Of three nitrogen fertilizer types, the amide-form nitrogen source was better to the formation and accumulation of gliadin as well as its four fractions.展开更多
文摘A case of Meropenem as a novel antibacterial agent to suppress and eliminate Agrobacterium tumefaciens in the Agrobacterium-mediated transformation of orchid protocorm-like bodies （PLBs） has been reported in this article. The in vitro activities of meropenem and four comparator antibacterial agents against three Agrobacterium tumefaciens strains, LBA4404, EHA101, and GV3101, were assessed. In addition, the effect of meropenem on the growth of Dendrobium phalaenopsis PLBs was determined. Compared with other commonly used antibiotics （including ampicillin, carbenicillin, cefotaxime, and cefoperazone）, meropenem showed the highest activity in suppressing all tested A. tumefaciens strains （minimum inhibitory concentration [MIC] 〈 0.5 mg L^-1, which is equal to minimum bactericidal concentration [MBC]）. Meropenem, at all tested concentrations, except for 10 mg L^-1 concentration, had little negative effect on the growth of orchid tissues. The A. tumefaciens strain EHA101 in genetic transformation with vector plG121Hm in infected PLBs of the orchid was visually undetectable after a two-month subculture in 1/2 MS medium with 50 mg L^-1 meropenem and 25 mg L^-1 hygromacin. The expression and incorporation of the transgenes were confirmed by GUS histochemical assay and PCR analysis. Meropenem may be an alternative antibiotic for the effective suppression of A. tumefaciens in genetic transformation.
文摘Gliadin, the major storage protein in endosperm, affects grain quality in spring wheat by its content and composition. Eighteen cultivars differing in HMW-GS were used in the study to approach the accumulation pattern of gliadin fractions α, β, γ, ω and regulation of three kinds of nitrogen source. The results showed that the content of gliadin in grains increased gradually along with the process of grain-filling, but the accumulation intensity and final content differed evidently among cultivars with different HMW-GS composition. Of all the subunit types used here, cultivars with subunits 7＋9 and 2＋12 had smaller accumulation intensity and lower final content. During grain-filling, 4 gliadin fractions had the same increase trend, but differed in accumulation course. The dynamic trends of gliadin accumulation were similar in different nitrogen treatments whose effects on initial amount, accumulation intensity and final level of accumulation varied with cultivars. Of three nitrogen fertilizer types, the amide-form nitrogen source was better to the formation and accumulation of gliadin as well as its four fractions.
