• Korean Journal of Veterinary Research
• /
• v.50 no.3
• /
• pp.239-246
• /
• 2010

Among 203 avian pathogenic Escherichia coli (APEC) isolated from poultry with colibacillosis in korea, 14 isolates were selected from total 68 isolates transferred R plasmid and classified into 5 groups on the basis of antimicrobial minimal inhibitory concentration (MIC) pattern, farm source and O serotype. An association between clonal origin and R plasmid of them was investigated by R plasmid profile, restriction endonuclease analysis and pulsed-field gel electrophoresis (PFGE). The strains that showed the same or very similar antimicrobial MIC pattern, but different farm source and O serotype, revealed different PFGE pattern, which seemed to be different clonal origin. And the strains that showed the same MIC pattern and O serotype, revealed different PFGE pattern, seemed to be originated from different clone. Also the strains showing the same MIC pattern and farm source, but different O serotype, revealed to be different clonal origin. The strains that showed the same or similar MIC pattern, farm source, and O serotype, revealed identical or similar PFGE pattern, which seemed to belong to be one clone. Meanwhile, horizontal transfer of R plasmid seems to be common in APEC with regardless of O serotype and clone of the strains. These results indicate that rapid and accurate epidemiological survey of APEC can be possible by the combination of O serotyping, plasmid profiling and PFGE analysis following the classification of them into groups of antimicrobial drug resistance pattern.

• Korean Journal of Veterinary Service
• /
• v.41 no.4
• /
• pp.257-262
• /
• 2018

Avian pathogenic E. coli (APEC) causes severe economic losses in the poultry farms, due to systemic infections leading to lethal colisepticemia. It causes a variety of diseases from air sac infection to systemic spread leading to septicemia. Secondary infection contains opportunistic infections due to immunosuppression disease. Collibacillosis causes the great problems in the poultry industry in Korea. Thus, it is necessary to identify and classify the characteristics of E. coli isolate of chicken origin to confirm the diversity of symptoms and whether they are transmitted among the farms. Fragment analysis is identify the difference in the number of Variable-Number Tandem-Repeats (VNTRs) for genotyping. VNTRs have repeating structure (Microsatellite, Short tandem repeats; STR, Simple sequence repeats; SSR) in the chromosome. This region can be used as a genetic marker because of its high mutation rate. And various lengths of the amplified DNA fragment cause the difference in the number of repetition of the DNA specific site. The number of repetition sequences indicates the separated size of fragments, so the each fragments can be distinguished by specific samples. The results of the sample show that there is no difference in six microsatellite loci (yjiD, aidB, molR_1, ftsZ, b1668, yibA). There are differences among the farms in relation of the number of repetitions of other six microsatellite loci (ycgW, yaiN, yiaB, mhpR, b0829, caiF). Four (ycgW, yiaB, b0829, caiF) of these six microsatellite loci show statistically significant differences (P<0.05). It means that the analysis using four microsatellite loci including ycgW, yiaB, b0829, and caiF can confirm among the farms. Five E. coli samples in one farm have same SSR repetition at all markers. But, there are significant differences from other farms at Four (ycgW, yiaB, b0829, caiF) microsatellite loci. These results emphasize again that the four microsatellite loci makes a difference in the amplified DNA fragments, enabling it to be used for E. coli genotyping.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.11
• /
• pp.1447-1455
• /
• 2009

Two novel avian $\beta$-defensins (AvBDs) isolated from duck liver were characterized and their homologies with other AvBDs were analyzed. They were shown to be duck AvBD9 and AvBD10. The mRNA expression of the two genes was analyzed in 17 different tissues from 1-28-day-old ducks. AvBD9 was differentially expressed in the tissues, with especially high levels of expression in liver, kidney, crop, and trachea, whereas AvBD10 was only expressed in the liver and kidney of ducks at all the ages investigated. We produced and purified GST-tagged recombinant AvBD9 and AvBDI0 by expressing the two genes in Escherichia coli. Both recombinant proteins exhibited antimicrobial activity against several bacterial strains. The results revealed that both recombinant proteins retained their antimicrobial activities against Staphylococcus aureus under a range of different temperatures ($-70^{\circ}C-100^{\circ}C$) and pH values (pH 3-12).

• Korean Journal of Veterinary Research
• /
• v.46 no.1
• /
• pp.13-19
• /
• 2006

Generally known psittacosis or ornithosis is a disease of birds caused by the bacterium Chlamydia psittaci. Humans are accidential hosts and are most commonly infected from avian sources. It raises hepatitis or neurosis. As major outer membrane protein (MOMP) of Chlamydia psittaci has been known to play a role in the avoidance of host immune defenses, research on developing a Chlamydia vaccine has focused on the MOMP. In this study, the gene encoding the major outer membrane protein (MOMP) of the Chlamydia psittaci strain 6BC was cloned and expressed in Escherichia coli strain M-15. The recombinant DNA was cloned by fusion prokaryotic expression vector pQE30-GFPII. Expression of the recombinant protein was performed in E. coli and was induced by IPTG. The size of expressed recombinant protein is 74.220 kDa (MOMP, 43.260 kDa; GFP expression region, 30 kDa; $6{\times}His$ tag, 960Da). This protein was purified by using his-tagging-inclusion body. Recombinant protein was reconfirmed through ELISA test and western blot with antibody against pQE30-GFPII. It will be useful antibody development.

• Journal of the Korea Convergence Society
• /
• v.12 no.4
• /
• pp.201-206
• /
• 2021

Damage to the highly pathogenic avian influenza virus(H5N1) continues to increase, but there is a lack of antiviral research. In this study, we analyze antiviral properties on H5N1 by coating Cu/TiO2 photocatalyst on polyethylene films. The specimen was manufactured a photocatalyst master batch and coated both sides of the 3-layer polyethylene fabric at 280℃ from the extrusion coating machine. The results showed a 99.9% decrease in the Staphylococcus aureus and Escherichia coli. In particular, H5N1 type highly pathogenic avian influenza viruses, which is capable of human infection, has been found to decrease 99.9% within five minutes of contact with Cu/TiO2 films. Antibacterial effects of films coated with photocatalyst are known, but this study also confirmed the antiviral effects.

• Korean Journal of Veterinary Research
• /
• v.57 no.2
• /
• pp.117-126
• /
• 2017

Bovine mastitis is an important microbial disease in the dairy industry. We investigated the frequencies of bacterial pathogens in 62 farms and pathogen antibiotic resistance from mastitis samples (n = 748). We tested the antimicrobial activity of chicken and duck egg white and lysozyme purified from chicken egg white. Moreover, we compared the microbiomes of normal and mastitic raw milk obtained by 16S rRNA gene pyrosequencing and culture methods. The results showed that the frequencies of Gram-positive pathogens (Enterococcus faecalis 37% and Staphylococcus aureus 36%) were higher than that of a Gram-negative pathogen (Escherichia coli 15%). Resistance frequencies to ampicillin and norfloxacin were lowest in Staphylococcus aureus (21%), Enterococcus faecalis (23%), and Escherichia coli (33%), and the antimicrobial activity of chicken egg white was higher than those of lysozyme and duck egg white. Pyrosequencing results revealed clear differences between the microbiomes of mastitic and normal raw milk samples and revealed a slightly similar, but clearly different, composition of pathogens compared to that from the culture method. Thus, pyrosequencing may be useful for elucidating changes in microbiomes during mastitis progression and treatment. A chicken egg white and antibiotic combination may help with mastitis treatment; however, further studies are needed.

• Animal Bioscience
• /
• v.35 no.4
• /
• pp.631-637
• /
• 2022

Objective: Surface disinfection is important in the proper running of livestock farms. However, disinfection of farm equipment and facilities is difficult because they are made of different materials, besides having large surface areas and complex structures. 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC) is a quaternary ammonium salt-based disinfectant that attaches to various surfaces by forming covalent bonds and maintains its disinfecting capacity for a considerable time. Our aim was to evaluate the potential use of Si-QAC for disinfection of farm equipment and facilities. Methods: The short- and long-term antimicrobial and antiviral effects of Si-QAC were evaluated in both laboratory and farm settings using modified quantitative assessment method based on the standard operating procedures of the United States Environmental Protection Agency. Results: Si-QAC was highly effective in controlling the growth of the Newcastle disease virus and avian pathogenic Escherichia coli. Electron microscopy revealed that the mechanism underlying the disinfection activity of Si-QAC was associated with its ability to damage the outer membrane of the pathogen cells. In the field test, Si-QAC effectively reduced viral contamination of surfaces of equipment and space. Conclusion: Our results suggest that Si-QAC has great potential as an effective chemical for disinfecting farm equipment and facilities. This disinfectant could retain its disinfection ability longer than other commercial disinfectants and contribute to better farm biosecurity.

• Korean Journal of Poultry Science
• /
• v.34 no.4
• /
• pp.287-294
• /
• 2007

Current study was conducted to identify the effects of dietary supplementation of Aspergillus oryzae ferments (AOF) cultured under normal (NAOF) or nitrogen-deficient (NMAOF) environment on feed efficiency, nutrient digestibility for broiler chicks. Fecal microbes and ammonia gas production were also determined. A total of 168 male Avian chicks, 2-wk-old, were randomly assigned into 56 cages, three chicks per cage. There were seven treatments (Control, NAOF 0.05, 0.1, 0.5%, NMAOF 0.05, 0.1, 0.5%), with 8 replicates (cages) per treatment. There was no significant difference in nutrient digestibility between two AOF groups, but the digestibility was greatly(p<0.05) improved by AOF supplementation. Total microbial account significantly (p<0.05) differed between the treatment groups with the highest number for NNAOF, followed by NAOF and control. In the case of Escherichia coli and Salmonella, the AOF supplementation significantly (p<0.05) reduced their numbers in feces, with a particular reduction in NNAOF group. Levels of ammonia gas generation were in order of control>NAOP>NNAOP. The current data implied that AOF supplementation, particularly grown under nitrogen-deficient environment, would be a feasible way to improve feed efficiency for broiler production, as well as to reduce environmental cost. However, further studies remain for industrial application.

• The Korean Journal of Zoology
• /
• v.27 no.2
• /
• pp.103-116
• /
• 1984

The structural gene of rabbit hemoglobin was cloned into Pst I site of pBR322 in E. coli. The complementary DNA (cDNA) was synthesized from rabbit globin mRNA with avian myeloblastosis viral reverse transcriptase, and then RNA was destroyed at pH 11. The double stranded cDNA was synthesized with both Klenow fragment of E. coli DNA polymerase I and reverse transcriptase and then the hairpin loop was opened with Sl nuclease. Double stranded cDNA was subsequently tailed with dCTP and annealed to dGMP-tailed vector DNA. After transformation and initial screening of appropriate clones by plasmid size, the cloned colonies were identified by in situ colony hybridization using by plasmid size, the cloned colonies were identified by in situ colony hybridization using $[^32P]$-labeled cDNA probes and characterized the inserts with restriction endonucleases. The expression of cloned globin gene was investigated by standard radioimmunoassay using rat anti-rabbit Hb serum as primary antibody and goat antirat IgG serum as secondary antibody. The result suggested that the chimeric proteins (the part of $\\beta$-lactamase from the vector pBR322 and globin from rabbit) were supposedly produced in E. coli and the product had the antigenic determinant of rabbit hemoglobin.

• Journal of Microbiology and Biotechnology
• /
• v.25 no.12
• /
• pp.2082-2089
• /
• 2015

Avian beta-defensin 9 (AvBD9) is a small cationic peptide consisting of 41 amino acids that plays a crucial rule in innate immunity and acquired immunity in chickens. Owing to its wide antibacterial spectrum, lack of a residue, and failure to induce bacterial drug resistance, AvBD9 is expected to become a substitute for conventional antibiotics in the livestock and poultry industries. Using the preferred codon of Pichia pastoris, the mature AvBD9 peptide was designed and synthesized, based on the sequence from GenBank. The P. pastoris constitutive expression vector pGHKα was used to construct a pGHKα-AvBD9 recombinant plasmid. Restriction enzyme digestion was performed using SacI and BglII to remove the ampicillin resistance gene, and the plasmid was electrotransformed into P. pastoris GS115. High-expression strains with G418 resistance were screened, and the culture supernatant was analyzed by Tricine-SDS-PAGE and western blot assay to identify target bands of about 6 kDa. A concentrate of the supernatant containing AvBD9 was used for determination of antimicrobial activity. The supernatant concentrate was effective against Escherichia coli, Salmonella paratyphi, Salmonella pullorum, Pseudomonas aeruginosa, Enterococcus faecalis, and Enterobacter cloacae. The fermentation product of P. pastoris carrying the recombinant AvBD9 plasmid was adjusted to 1.0 × 10⁸ CFU/ml and added to the drinking water of white feather broilers at different concentrations. The daily average weight gain and immune organ indices in broilers older than 7 days were significantly improved by the AvBD9 treatment.