• Korean Journal of Veterinary Research
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• v.51 no.1
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• pp.29-35
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• 2011

Lack of hygiene and puerperal mastitis are common causes of bacterial diseases in nursing neonates. The aim of this study was to isolate microorganisms from milk samples of healthy female Jindo dogs with suckling puppies and to investigate antimicrobial susceptibility against the isolated bacteria. Milk samples were collected from 120 udders of 12 lactating Jindo dogs that were 2~4 years old without any clinical diseases including mastitis. Bacteria were isolated from 64 milk samples (53.3%), either singly (76.6%) or in combination (23.4%). Staphylococcus (S.) spp. was the most common microorganisms (74.7%) isolated from canine milk, followed by Haemophillus spp. (10.9%), Streptococcus spp. (9.6%), Gardnerella spp. (2.4%) and Moraxella spp. (2.4%). The most frequently isolated organism was S. warneri (31.3%). Antimicrobial susceptibility of these bacteria was tested with 17 antimicrobial agents by Kirbyand Bauer standardized disc diffusion method. Results indicated that bacteria isolated from healthy canine milk were mostly susceptible to amoxicillin-clavulanic acid, cephalothin and ceftiofur, but were resistant to erythromycin, neomycin and tetracycline.

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.337-340
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• 2007

Pseudomonas syringae Pv. syringae is a causal agent of bacterial blossom blight of kiwifruit in Korea. Eleven strains of the pathogen were isolated from different kiwifruit orchards in Korea and the plasmid profiles were obtained by pulsed-field gel electrophoresis. They could be clustered into six groups according to the number and size of plasmids. The number of plasmids per strain and size of these plasmids ranged from 0 to 4 and from 22 to 160 kb, respectively. Among them, four strains belonging to Group III which harbored two plasmids were resistant to copper sulfate. Southern blot hybridization of the plasmid DNA indicated that the copper resistance determinant was carried on a 48 kb plasmid.

• IMMUNE NETWORK
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• v.4 no.2
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• pp.73-80
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• 2004

Viruses are obligate intracellular parasites which cause infection by invading and replicating within cells. The immune system has mechanisms which can attack the virus in extracellular and intracellular phase of life cycle, and which involve both non-specific and specific effectors. The survival of viruses depends on the survival of their hosts, and therefore the immune system and viruses have evolved together. Immune responses to viral infection may be variable depending on the site of infection, the mechanism of cell-to-cell spread of virus, physiology of the host, host genetic variation, and environmental condition. Viral infection of cells directly stimulates the production of interferons and they induce antiviral state in the surrounding cells. Complement system is also involved in the elimination of viruses and establishes the first line of defence with other non-specific immunity. During the course of viral infection, antibody is most effective at an early stage, especially before the virus enters its target cells. The virus- specific cytotoxic T lymphocytes are the principal effector cells in clearing established viral infections. But many viruses have resistant mechanism to host immune responses in every step of viral infection to cells. Some viruses have immune evasion mechanism and establish latency or persistency indefinitely. Furthermore antibodies to some viruses can enhance the disease by the second infection. Immune responses to viral infection are very different from those to bacterial infection.

• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.4
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• pp.691-703
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• 1998

Saliva is obviously potential medium to protect the dental caries by not only physical clearing effect, but aggregating action of protein with bacteria. Nevertheless, we still do not understand how the dental caries occur and what brings the individual difference in caries prevalence. In the regards of dental caries prevalence, we hypothesized that the composition of salivary protein might be different from caries susceptible group to caries resistant group. The purposes of this experiment were focused on the molecular analysis of salivary proteins from the subjects who were involved in multiple caries. Electrophoretic analysis was done on the whole saliva collected from the children with and without multiple caries. We found 86.2% of subjects with multiple caries has approximately 120 KDa protein band while 30.4% in the healthy subjects. And the concentration of the total protein on the subjects with multiple caries is significantly higher than that of the healthy group. However, it turned out that the difference of the salivary composition does not affect the bacterial adhesion to hydroxyapatite bead. With regards of enzymes in saliva, the activity of ${\alpha}-amylase$ and lactate dehydrogenase does not have any significant difference between both groups. However, the concentrations of $Na^+\;and\;Cl^-$ in saliva from multiple caries group is higher than that of the control group. Taken all together, it may be concluded that 120 KDa protein in saliva may be associated with the process of dental caries, also the high concentration of protein and $Na^+,\;Cl^-$ in saliva may be linked to dental caries development as a cofactors.

• Korean journal of applied entomology
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• v.4
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• pp.29-32
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• 1965

1. The 30 isolates of Xanthomonas oryzae collected from various places in Korea were classified into 2 strains in A' and B, by the 4 kinds of Japanese bacteriophages as follow; A' strain; Susceptible to $OP_1$ and $OP_2$ but not to $OP_1h$ and $OP_1h_2$. B strain; Susceptible to $OP_1h$, $OP_1h_2$ and $OP_2$ but not to $OP_1$. Of these bacterial strains, A' strain, a little different to A strain in Japan, was susceptible to $OP_1h_2$, while A' strain was resistant to $OP_1h_2$, 2. A' strain was widely and commonly distributed throughout this country, In geographical distribution, it was generally known that A' strain was distributed in south of Kyunggi-Do, whereas B strain was distributed north of Suwon area. 3. No specific tendency was found in the distribution of these strains in same variety.

• Food Science of Animal Resources
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• v.31 no.4
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• pp.609-616
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• 2011

In this study, a LCH1227 bacterial strain that possesses anti-listerial activity was isolated from fermented food and identified as Lactobacillus salivarius LCH1227 based on its morphological and biochemical properties, as well as its 16S rRNA gene sequences. Anti-listerial substance also inhibited the growth of various Gram-positive bacteria, such as vancomycinresistant Enterococcus faecalis, Streptococcus agalactiae, Bacillus cereus, Lactobacillus fermentum. The highest level of production of antimicrobial substances from L. salivarius LCH1227 occurred during the early stationary phase. The antilisterial activity was found to be stable over a broad range of pH values (2.0-12.0) and after heat treatment. However, it was inactivated by proteolytic enzymes, indicating its proteinaceous nature. The apparent molecular mass of the partially purified anti-listerial substance, as measured by Tricine-SDS-PAGE, was approximately 5 kDa.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.11-18
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• 2020

Bacteria of the genus Enterococcus are of importance in food fermentations as well as their use as probiotics in humans and livestock. However, they are also important nosocomial pathogens that cause infections. Some strains are resistant to multiple antibiotics and possess virulence factors. The role of Enterococcus species in disease has raised issues on their safety for use in foods or as probiotics. First, this review summarized the positive and negative traits of Enterococcus spp. to illustrate the controversial nature of this bacterial genus and discussed the current genomic approaches can eliminate pathogenic strains. Then, this review examined the current status of starter development for traditional food fermentations and the regulation on the approval of novel food microorganisms in Korea to point out problems in the regulation. Based on the conclusions from the studies on Enterococcus spp., we suggested the direction of safety assessment of novel food microorganisms in Korea.

• The Plant Pathology Journal
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• v.15 no.3
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• pp.137-143
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• 1999

A novel chromosomal gene tagging technique using a specific fragment of the fatty acid desaturase-like open reading frame (des-like ORF) from the tox-argK gene cluster of Pseudomonas syringae pv. phaseolicola was developed to identify Xanthomonas spp.released into the environment as biocontrol agents. X. campestris pv. convolvuli FB-635, a pathogen of Convolvulus arvensis L., (bindweed), was chosen as the organism in which to develop and test the system. A 0.52 kb DES fragment amplified from P. syringae pv. phaseolicola C-199 was inserted into pGX15, a cosmid clone containing a 10.3 kb Eco RI-HindIII fragment derived from the xanthomonadin biosynthetic gene cluster contained in plasmid pIG102, to create a pigG::DES insertion. The 10.8 kb EcoRI-BamHI fragment carrying the pigG:: DES insertion was cloned into pLAFR3 to generate pLXP22. pLXP22 was then conjugated into X. campestris pv. convolvuli FB-635 and the pigG::DES insertion integrated into the bacterial chromosome by marker exchange. Rifampicin resistant, tetracycline sensitive, starch hydrolyzing, white colonies were used to differentiate the marked strain from yellow pigmented wild-type ones. PCR primers specific for the unique DES fragment were used for direct detection of the marked strain. Result showed the marked strain could be detected at very low levels even in the presence of high levels of other closely related or competitive bacteria. This PCR-based DES-tagging system provides a rapid and specific tool for directly monitoring the dispersal and persistence of Xanthomonas spp.released into the environment.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.203-209
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• 1987

The substances obtained from the leaf, stem and root of tobacco plants inoculated with avirulent and virulent isolates of Pseudomonas solanacearum were at R_f\;0.6$ and R_f\;0.9$ on TLC plate, respectively. Both substances showed antibacterial activities not only on P. solanacearum but also on Erwinia carotovora subsp. carotovora and Escherichia coli in vitro. However, the antibacterial substances were not detectable from the filtrate of the autoclaves tobacco sap medium, in which the avirulent or virulent bacterium was cultured for 3 days. Peroxidase and poly phenoloxidase activities and their isozyme patterns did not differ significantly between plants treated with the virulent and avirulent isolates, or between the susceptible cultivar BY 4 and the resistant cultivar NC 82. However, activities of the two enzymes were increased in leaves of the susceptible cultivar BY 4 treated with either the virulent or the avirulent isolate.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.223-228
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• 2016

Shigella is a common cause of bacterial enteritis worldwide. Shigella sonnei accounts for 90% of Shigella infections and Shigella flexneri is rarely reported in Korea. Although the incidence of Shigella infection has decreased, the incidence of organisms with antibiotic resistance has gradually increased in Korea. An outbreak of extended-spectrum ${\beta}-lactamase$ (ESBL)-producing S. sonnei in children was reported in Korea; however, ESBL-producing S. flexneri has not yet been reported. We report the first two cases of multidrug-resistant CTX-M-14-producing S. flexneri infections in Korean children.