• Plant Biotechnology Reports
• /
• v.3 no.4
• /
• pp.277-283
• /
• 2009

One of the limitations to conducting maize Agrobacterium-mediated transformation using explants of immature zygotic embryos routinely is the availability of the explants. To produce immature embryos routinely and continuously requires a well-equipped greenhouse and laborious artificial pollination. To overcome this limitation, an Agrobacterium-mediated transformation system using explants of type II embryogenic calli was developed. Once the type II embryogenic calli are produced, they can be subcultured and/or proliferated conveniently. The objectives of this study were to demonstrate a stable Agrobacterium-mediated transformation of maize using explants of type II embryonic calli and to evaluate the efficiency of the protocol in order to develop herbicide-resistant maize. The type II embryogenic calli were inoculated with Agrobacterium tumefaciens strain C58C1 carrying binary vector pTF102, and then were subsequently cultured on the following media: co-cultivation medium for 1 day, delay medium for 7 days, selection medium for $4{\times}14$ days, regeneration medium, and finally on germination medium. The T-DNA of the vector carried two cassettes (Ubi promoter-EPSPs ORF-nos and 35S promoter-bar ORF-nos). The EPSPs conferred resistance to glyphosate and bar conferred resistance to phosphinothricin. The confirmation of stable transformation and the efficiency of transformation was based on the resistance to phosphinothricin indicated by the growth of putative transgenic calli on selection medium amended with $4mg\;1^{-1}$ phosphinothricin, northern blot analysis of bar gene, and leaf painting assay for detection of bar gene-based herbicide resistance. Northern blot analysis and leaf painting assay confirmed the expression of bar transgenes in the $R_1$ generation. The average transformation efficiency was 0.60%. Based on northern blot analysis and leaf painting assay, line 31 was selected as an elite line of maize resistant to herbicide.

• Journal of Microbiology
• /
• v.44 no.4
• /
• pp.383-395
• /
• 2006

Four different Trichoderma strains, T. harzianum CECT 2413, T. asperellum T53, T. atroviride T11 and T. longibrachiatum T52, which represent three of the four sections contained in this genus, were transformed by two different techniques: a protocol based on the isolation of protoplasts and a protocol based on Agrobacterium-mediated transformation. Both methods were set up using hygromycin B or phleomycin resistance as the selection markers. Using these techniques, we obtained phenotypically stable transformants of these four different strains. The highest transformation efficiencies were obtained with the T. longibrachiatum T52 strain: 65-70 $transformants/{\mu}g$ DNA when transformed with the plasmid pAN7-1 (hygromycin B resistance) and 280 $transformants/l0^7$ spores when the Agrobacterium-mediated transformation was performed with the plasmid pUR5750 (hygromycin B resistance). Overall, the genetic analysis of the transform ants showed that some of the strains integrated and maintained the transforming DNA in their genome throughout the entire transformation and selection process. In other cases, the integrated DNA was lost.

• Korean Journal of Plant Tissue Culture
• /
• v.25 no.3
• /
• pp.201-206
• /
• 1998

To develop the fruits of cucumber (Cucumis sativus L.) producing high yields of superoxide dismutase (SOD), the MnSOD cDNA from pea (Pisum sativum) under the control of the cauliflower mosaic virus 35S promoter was introduced into cucumber using Agrobacterium tumefaciens (strain LBA 4404)-mediated transformation. The kanamycin-resistant shoots were selected on the selection medium containing MS basal salt, 1.0 mg/L zeatin, 0.1 mg/L IAA, 300 mg/L claforan, and 100 mg/L kanamycin. After 6 weeks of culture on the selection medium, the shoots were transferred to MS medium containing 0.2 mg/L NAA to induce roots. PCR analysis using the primers for neomycin phosphotransferase (NPTII) gene revealed that three plantlets were transformed. The fruits of one transgenic plant had approximately 3.2-fold higher SOD activity than those of non-transgenic plants. MnSOD isoenzyme band was strongly detected on native gel in fruits of transgenic plants.

• Mycobiology
• /
• v.50 no.5
• /
• pp.374-381
• /
• 2022

In the mating of filamentous basidiomycetes, dikaryotic mycelia are generated through the reciprocal movement of nuclei to a monokaryotic cytoplasm where a nucleus of compatible mating type resides, resulting in the establishment of two different dikaryotic strains having the same nuclei but different mitochondria. To better understand the role of mitochondria in mushrooms, we created four sets of dikaryotic strains of Lentinula edodes, including B2×E13 (B2 side) and B2×E13 (E13 side), B5×E13 (B5 side) and B5×E13 (E13 side), E8×H3 (E8 side) and E8×H3 (H3 side), and K3×H3 (K3 side) and K3×H3 (H3 side). The karyotypes and mitochondrial types of the dikaryotic strains were successfully identified by the A mating type markers and the mitochondrial variable length tandem repeat markers, respectively. Comparative analyses of the dikaryotic strains on the mycelial growth, substrate browning, fruiting characteristics, and mitochondrial gene expression revealed that certain mitochondria are more effective in the mycelial growth and the production of fruiting body, possibly through the activated energy metabolism. Our findings indicate that mitochondria affect the physiology of dikaryotic strains having the same nuclear information and therefore a selection strategy aimed at mitochondrial function is needed in the development of new mushroom strain.

• Microbiology and Biotechnology Letters
• /
• v.10 no.1
• /
• pp.33-37
• /
• 1982

The work has been carried out for the development of antifungal antibiotics possessing curative effect in the control of sheath blight disease of rice plant. Soil samples were collected from over 1600 spots throughout the country. More than 1300 specimens which seem to be the genus Streptomyces were isolated from the soil samples. Screening procedures consist of respective processes by four steps. Those are growth inhibition test in liquid culture, paper disk method, dendroid test and green house test. 102 isolates appeared to be active against Pellicularia sasakii when all specimens isolated were examined by the first growth inhibition test. Finally a strain of Streptomyces forming strong antifungal substances against P. sasakii was selected from a soil sample of Mt. Soyo, Kyeongi Province. Antifungal substances formed by the strain were isolated and purified from the culture broth and examined for antimicrobial activities as to be specific against fungi but not active on bacterial growth.

• Applied Biological Chemistry
• /
• v.51 no.2
• /
• pp.93-101
• /
• 2008

This study was conducted to obtain a good probiotic strain of L. acidophilus from infant feces which have the acid and bile tolerance. The selection criteria for the strain included antimicrobial activity, serum cholesterol reduction, resistance to the hydrogen peroxide, angiotensin converting enzyme (ACE) inhibition activity and iron solubility. To this end, five probiotic Lactobacillus strains have been isolated from infant feces. Especially, L. acidophilus SD 105 had strong antimicrobial activity against Listeria sp., high deconjugation activity in the medium which contained 0.5% of glycocholate (GCA) and high resistance to the hydrogen peroxide. L. acidophilus SD 102 showed the highest ACE inhibition activity among the tested cultures and L. acidophilus SD 103 showed iron solubility of more than 70%.

• Microbiology and Biotechnology Letters
• /
• v.45 no.2
• /
• pp.143-148
• /
• 2017

Ten Bacillus strains possessing amine oxidase activity were selected from 126 Bacillus isolates from meju and doenjang (two traditional Korean soybean foods). Among the isolates, two B. licheniformis strains (8MI05 and 8MS03) harbored the amine oxidase gene yobN. By conducting a gene search against published B. licheniformis genomes, the possession of yobN was proved to be a strain-specific property. Both strains degraded four types of biogenic amines (cadaverine, histamine, putrescine, and tyramine) supplemented in tryptic soy broth during their culture. A recombinant harboring yobN also degraded the four types of biogenic amines during cultivation. Both Bacillus strains could grow at a NaCl concentration of 14% and exhibited strain-specific protease and lipase activities.

• The Korean Journal of Pesticide Science
• /
• v.7 no.4
• /
• pp.296-301
• /
• 2003

This study was conducted to select low toxic insecticides against natural enemies, and to evaluate resistance stability and cross-resistance to resistance strain for the fulfillment of integrated pest management development. Toxicity of imidacloprid and spinosad to Amblyseius cucumeris was relatively low regardless of the adopting test methods. In addition, those to the Amblyseius fallacis was also low by slide dipping method. The slide dipping method was useful to eliminate repellency effect by mites to the tested insecticides. Mortality of A. fallacis to deltamethrin recorded in 1994 and 1999 was 21.6% and 7.4%, respectively. Meanwhile, the permethrin-resistanct strain of A. fallacis was maintained its resistance to deltamethrin. However, the cross-resistance to the newly introduced insecticides namely imidacloprid, fipronil, chlorfenapyr, abamectin, and spinosad. was relatively low.

• Research in Plant Disease
• /
• v.12 no.3
• /
• pp.267-271
• /
• 2006

Botrytis cinerea Pers. was found to be highly virulent to the grapevine plant, especially in greenhouse condition. Pseudomonas species play key roles for the biocontrol of many plant diseases especially in soil. Of the 83 isolates of Pseudomonas spp., a bacterial strain P84, isolated from tomato rhizosphere, was shown to suppress a wide range of phytopathogenic fungi in vitro. The isolate was identified as Pseudomonas putida on the basis of its bacteriological and genetic characteristics. The P. putida P84 strain carry the phlD gene for 2,4-diacetylphloroglucinol biosynthesis and may produce the antibiotics as an antagonistic mechanism involved in biocontrol. The antagonistic activity of the bacterium has a promising implication for its use as a biocontrol agent to control grapevine gray mold.

• Food Science of Animal Resources
• /
• v.26 no.4
• /
• pp.497-502
• /
• 2006

The adhesion of 16 bifidobacterial strains, including 10 isolates from Korea infants, to Caco-2 cells and their cell surface hydrophobicity were tested. The results of adhesion and cell surface hydrophobicity of for various bifidobacterial strains were obtained and correlations between adhesion and hydrophobicity were strain-dependent properties. Any correlations between species of tested strains were not observed. Among the tested strains, Bifidobacterim longum D6, B. longum H4, B. thermophilum ATCC 25525, B. suis ATCC 27533, and B. animalis subsp. lactis BB12 had higher adherent properties and B. bifidum B3, B. longum D6, B. longum stronger hydrophobicity, respectively. Due to the strain-dependant correlation between adhesion to Caco-2 cells and cell surface hydrophobicity of bifidobacteria, these results provide a possible method for preliminary selection of bifidobacteria potentially adherent to Caco-2 cells by means of cell surface hydrophobic properties.