• Journal of Microbiology and Biotechnology
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• v.28 no.12
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• pp.1955-1970
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• 2018

Several genetic strategies have been proposed for the successful transformation and expression of microbial transgenes in model and crop plants. Here, we bring into focus the prominent applications of microbial transgenes in plants for the development of disease resistance; mitigation of stress conditions; augmentation of food quality; and use of plants as "bioreactors" for the production of recombinant proteins, industrially important enzymes, vaccines, antimicrobial compounds, and other valuable secondary metabolites. We discuss the applicable and cost-effective approaches of transgenesis in different plants, as well as the limitations thereof. We subsequently present the contemporary developments in targeted genome editing systems that have facilitated the process of genetic modification and manifested stable and consumer-friendly, genetically modified plants and their products. Finally, this article presents the different approaches and demonstrates the introduction and expression of microbial transgenes for the improvement of plant resistance to pathogens and abiotic stress conditions and the production of valuable compounds, together with the promising research progress in targeted genome editing technology. We include a special discussion on the highly efficient CRISPR-Cas system helpful in microbial transgene editing in plants.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.273.1-273
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• 1997

No Abstract, See Full Text

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.270-276
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• 2005

This study was conducted to examine whether a specific synthetic metalworking fluid (MWF), "A", in use for 10 months without replacement, displayed microbial resistance and to identify the additives associated with the control of microbial growth. Three synthetic MWF products ("A", "B", and "C") were studied every week for two months. Microbial deterioration of the fluids was assessed through evaluation by endotoxin, bacteria and fungi levels in the MWFs. In addition, formaldehyde, boron, ethanolamine, and copper levels were also studied to determine whether they influence microbial growth in water-based MWFs. Throughout the entire study in the sump where MWF "A" was used, bacteria counts were lower than 103 CFU/mL, and endotoxins never exceeded 103 EU/mL. These levels were significantly lower than levels observed in sumps badly deteriorated with microbes. Boron levels in MWF "A" ranged from 91.7 to 129.6 ppm, which was significantly higher than boron levels found in other MWF products. The total level of ethanolamine (EA) in MWF "A" ranged from 35,595 to 57,857 ppm (average 40,903 ppm), which was over ten times higher than that found in other MWFs. Monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) concentrations in MWF "A" were also significantly higher than seen in other MWFs. However, although EA and boron might improve anti-microbial performance, their abuse can pose a serious risk to workers who handle MWFs. From an industrial hygiene perspective, our study results stress that the positive synergistic effect of boron and EA in reducing microbial activity in MWF must be balanced with the potentially negative health effects of such additives. Our study also addresses the disadvantage of failing to comprehensively report MWF additives on Material Safety Data Sheets (MSDS). Future research in MWF formulation is needed to find the best level of EA and boron for achieving optimal synergistic anti-microbial effects while minimizing employee health hazards.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.197-207
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• 2012

This study investigated the role of plasmids and their relationship with the multiple antibiotic resistance of 30 Vibrios sp. isolated from molluscs and crustaceans sampled from the Kerala coastal waters of India. The biochemical identification and antibiotic resistance profiles were determined, followed by the plasmid profiles, conjugation and transformation efficiencies. The results showed a considerable difference in the level of bacterial resistance to various antibiotics; while all 30 strains were found to be MAR Vibrios sp. and their resistance patterns varied. All the strains were resistant to amoxycillin, ampicillin and carbeniciliin. 87% were resistant to rifampicin; 74% to cefuroxime; 67 to streptomycin; 53% to norfloxacin and ciprofloxacin and 47% to furazolidone and nalidixic acid. In addition to their antibiotic resistance, the plasmid DNA of the MAR Vibrios strains isolated from the molluscs and crustaceans was also studied. Nine strains isolated from crustaceans and molluscs were found to harbor 1-3 plasmids with sizes varying from 5. 98 kb to 19. 36 kb. The average transformation efficiency was about $5{\times}10^{-8}$ and the conjugation efficiency varied from $2.1{\times}10^{-3}$ to $10^{-9}$. A further study of antibiotic resistance patterns may be useful to test the extent of drug resistance in seafoods and help to devise a nationwide antibiotic policy.

• Infection and chemotherapy
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• v.50 no.4
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• pp.328-339
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• 2018

Background: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). Materials and Methods: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ${\geq}2$ non-${\beta}$-lactam antimicrobials. Results: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. Conclusion: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

• The Journal of the Korean dental association
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• v.41 no.2 s.405
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• pp.116-123
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• 2003

Antimicrobial Peptides are natural antibiotics evolved by many plants, invertebrate, and vertebrate to defend against the microbial infection. Antimicrobial peptides show a broad-spectrum antimicrobial activity with little opportunity for the development of resistance since they target microbial membranes that distinguish microbes from enkaryotic cells. The oral cavity is constantly exposed to microbial challenges and antimicrobial peptides play an important role in managing the oral health. With the increase of resistant micro-organisms to conventional antibiotics, antimicrobial peptides are attracting interests as novel antibiotics. In this review, the characteristics of antimicrobial of antimicrobial peptides including the classification, mechanism of action, resistance, and expression in the oral cavity have been discussed in the prospects of application to oral disease.

• Environmental Engineering Research
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• v.25 no.2
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• pp.238-242
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• 2020

Sediment microbial fuel cells (SMFCs) illustrated great potential for powering environmental sensors and bioremediation of sediments. In the present study, array anodes for SMFCs were fabricated with graphite rods as anode material and stainless steel plate as electric current collector to make it inconvenient to in situ settle down and not feasible for large-scale application. The results demonstrated that maximum power of 89.4 ㎼ was obtained from three graphite rods, twice of 43.3 ㎼ for two graphite rods. Electrochemical impedance spectroscopy revealed that three graphite rods resulted in anodic resistance of 61.2 Ω, relative to 76.0 Ω of two graphite rods. It was probably caused by the parallel connection of the graphite rods, as well as more biomass which could reduce the charge transfer resistance of the biofilm anode. The presently designed array configuration possesses the advantages of easy to enlarge the surface area, decrease in anodic resistance because of the parallel connection of each graphite rod, and convenience to berry into sediment by gravity. Therefore, the as prepared array node would be an effective method to fabricate large-scale SMFC and make it easy to in situ applicate in natural sediments.

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.274-276
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• 1997

Transformation of Coprinus congregatus with a linearized plasmid has been successfully carried out using phosphinothricin resistance gene as a dominant selectable marker. The transforming frequency was about 500 transformants per microgram of DNA using the protoplast-$CaCl_2$ method. The transforming vector pBARGEM 7-1 which had the phosphinothricin resistance gene was detected in the restriction enzyme fragments of chromosomal DNA from a transformant by Southern hybridization.

• Journal of Microbiology and Biotechnology
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• v.17 no.1
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• pp.96-103
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• 2007

Plant growth-promoting rhizobacteria (PGPR) have the potential to be used as microbial inoculants to reduce disease incidence and severity and to increase crop yield. Some of the PGPR have been reported to be able to enter plant tissues and establish endophytic populations. Here, we demonstrated an approach to screen bacterial endophytes that have the capacity to promote the growth of pepper seedlings and protect pepper plants against a bacterial pathogen. Initially, out of 150 bacterial isolates collected from healthy stems of peppers cultivated in the Chungcheong and Gyeongsang provinces of Korea, 23 putative endophytic isolates that were considered to be predominating and representative of each pepper sample were selected. By phenotypic characterization and partial 16S rDNA sequence analysis, the isolates were identified as species of Ochrobacterium, Pantoea, Pseudomonas, Sphingomonas, Janthinobacterium, Ralstonia, Arthrobacter, Clavibacter, Sporosarcina, Acidovorax, and Brevundimonas. Among them, two isolates, PS4 and PS27, were selected because they showed consistent colonizing capacity in pepper stems at the levels of $10^6-10^7CFU/g$ tissue, and were found to be most closely related to Pseudomonas rhodesiae and Pantoea ananatis, respectively, by additional analyses of their entire 16S rDNA sequences. Drenching application of the two strains on the pepper seedlings promoted significant growth of peppers, enhancing their root fresh weight by 73.9% and 41.5%, respectively. The two strains also elicited induced systemic resistance of plants against Xanthomonas axonopodis pv. vesicatoria.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.725-736
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• 2000

It is becoming increasingly apparent that periodontitis consists of mixture of diseases, most of which respond favorably to traditional mechanical therapy. Among these variants of the disease, some appear to be associated with unusual microbial infections and defective host defenses. Many of these fail to respond to conventional treatment. The recognition that some forms of periodontitis are refractory to standard periodontal therapy has given rise to a new classification of peridontitis. A series of 1692 subgingival microbial samples sent to a diagnostic microbiology laboratory included 738 samples that could be identified as compatible with a clinical diagnosis of refractory or recurrent periodontitis. In descending order of prevalence the associated microbiota included Bacteroides forsythus(85%) ,Fusobacterium species(78%), Spirochetes(67%), Campylobacter rectus(64%), Porphyromonas gingivalis(59%), Peptostreptococcus micros(58%), motile rods(46%), Prevotella intermedia(33%), Eikenella corrodens(13%), Capnocytophaga species(12%) ,and Actinobacillus actinomycetemcomitans(6%). Antibiotic resistance to tetracycline, penicillin G, or metronidazole was particularly noticeable for Fusobacterium species, Capnocytophaga species, and Actinobacillus actinomycetemcomitans. It was largely absent for Campylobacter rectus. No antibiotic data were obtained for Porphyromonas gingivalis or Bacteroides forsythus, as these species were detected by immunofluorescence. The results indicate that a substantial number of microorganisms associated with refractory periodontitis are variably resistant to commonly-used antibiotics. Diagnostic microbiology must be considered an essential adjunct to the therapist faced with periodontal lesions refractory to conventional treatment.