• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2005.10a
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• pp.122-123
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• 2005

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2004.10a
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• pp.115-115
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• 2004

• Korean Journal of Veterinary Service
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• v.33 no.3
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• pp.223-231
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• 2010

A total of 191 samples collected from the commercial swine farms located in Chungnam province were investigated by PCR to estimate the prevalence of Lawsonia (L.) intracellularis infection. In the group of the pigs with proliferative enteritis, 14 (93.3%) of 15 intestinal samples and 12 (80.0%) of 15 feces were positive in PCR. In contrast, a relatively low positive rate (18.0%, 29 of 161 samples) was determined in the group of normal healthy pigs. The group of pigs over 120 days showed the highest positive rates (26.8%, 15 of 56 samples). In the comparison of the sequences of 210bp for species specific fragments and 301bp for outer membrane protein, the isolates (L1. L2) showed almost 100% identity with the reference L. intracellularis (L08049, USA). For the sequences of partial 16s rDNA, the homologies among the 5 isolates (L1-L5) were 97.4% to 99.3%, and those of 5 sequences (L1-L5) versus 5 overseas reference strains of L. intracellularis ranged from 98.6% to 99.8%. In the comparison of the nucleotide sequences among 5 isolates and other species in Desulfovibrionales showed 82.4 to 99.5% identities. The 5 isolates shared relatively low identities (76.9% to 84.4%) with the species of alpha-proteobacteria. In phylogenetic analysis based on the 16s rDNA sequences, all of the 5 isolates (L1-L5) were located in the same branch with the strains of L. intracellularis that were previously isolated from the pigs in USA and China. Seven strains of Desulfovibrio sp. were clustered in the neighboring branches, whereas alpha and gamma Proteobacteria showed distant relationship with L. intracellularis strains. The present findings suggest that L. intracellularis infection is endemic in the swine farms in the regions, and that the domestic isolates maintained very limited genetic variation.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.551-559
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• 2004

Shiga toxin-producing Escherichia coli (STEC) causes various clinical signs in human and animals, and has been indicated as a global enteropathogen with zoonotic importance. In this study, the feces of healthy pigs were collected from the slaughtered pigs of Daejon abattoir during the period from December 2001 to October 2002. Of 326 specimens, 13 STEC were confirmed by culture, PCR and colony hybridization. The isolates were further studied for toxin types, pathogenic factors, plasmid profiles, and antimicrobial resistance to characterize the genetic and toxigenic properties. In PCR, all of 13 isolates were evident to have shiga toxin gene (stx). Of 13 isolates stx1 gene was detected in 4 and stx2 gene in 9. The genes of eaeA, hlyA and rfbE were not present in any isolates. In colony hybridization using shiga toxin common primer (STXc), 2 to 9 per 100 colonies subcultured from 13 isolates showed the positive reaction. In the examination for plasmid profiles of the isolates, one to eleven plasmids with varying sizes of 1.0 Kb to 100 Kb were detected, and the 13 STEC could be classified into four groups by the plasmid patterns. The antimicrobial resistance patterns of the isolates were comparably corresponded with the plasmid profile patterns.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.745-753
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• 2008

Gene-manipulated mice were discovered for the first time about a quarter century ago. Since then, numerous sophisticated technologies have been developed and applied to answer key questions about the fundamental roles of the genes of interest. Functional genomics can be characterized into gain-of-function and loss-of-function, which are called transgenic and knock-out studies, respectively. To make transgenic mice, the most widely used technique is the microinjection of transgene-containing vectors into the embryonic pronucleus. However, there are critical drawbacks: namely position effects, integration of unknown copies of a foreign gene, and instability of the foreign DNA within the host genome. To overcome these problems, the ROSA26 locus was used for the knock-in site of a transgene. Usage of this locus is discussed for the gain of function study as well as for several brilliant approaches such as conditional/inducible transgenic system, reproducible/inducible knockdown system, specific cell ablation by Cre-mediated expression of DTA, Cre-ERTM mice as a useful tool for temporal gene regulation, MORE mice as a germ line delete and site specific recombinase system. Techniques to make null mutant mice include complicated steps: vector design and construction, colony selection of embryonic stem (ES) cells, production of chimera mice, confirmation of germ line transmission, and so forth. It is tedious and labor intensive work and difficult to approach. Thus, it is not readily accessible by most researchers. In order to overcome such limitations, technical breakthroughs such as reporter knock-in and gene knock-out system, production of homozygous mutant ES cells from a single targeting vector, and production of mutant mice from tetraploid embryos are developed. With these upcoming progresses, it is important to consider how we could develop these systems further and expand to other animal models such as pigs and monkeys that have more physiological similarities to humans.

• Journal of Embryo Transfer
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• v.32 no.2
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• pp.53-58
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• 2017

It is very difficult to get the information about semen quality analysis in transgenic pigs because of limited numbers and research facilities. Therefore, in the present study, we analyzed the semen quality of transgenic boars generated for xenotransplantation research. Briefly, the semen samples were collected from 5 homozygous ${\alpha}1,3$-Galactosyltransferase knock-out ($GalT^{-/-}$) transgenic boars and immediately transported to the laboratory. These semen samples were decupled with DPBS and conducted to analyze semen parameters by a computer-assisted semen analysis (CASA) system. The boar semen were examined all 12 parameters such as total motility (TM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), and hyperactivated (HYP), etc. In results, among the 5 $GalT^{-/-}$ boars, three boars (#134, 144, and 170) showed normal range of semen parameters, but #199 and 171 boars showed abnormal ranges of semen parameters according to standard ranges of semen parameters. Unfortunately, #171 boar showed azoospermia symptom with rare sperm counts in the original semen. Conclusively, assessment of semen parameters by CASA system is useful to pre-screening of reproductively healthy boar prior to natural mating and artificial insemination for multiplication and breeding.

• Reproductive and Developmental Biology
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• v.31 no.1
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• pp.15-20
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• 2007

To search of a new porcine pheromonal odorant for biostimulation control system technologies to offer a potentially useful and practical way to improve reproductive efficiency in livestock species, the two dimensional quantitative structure-activity relationship (QSAR) models between physicochemical parameters as descriptors of 2-cyclohexyloxytetrahydrofurane (A), 2-phenoxytetrahydrofurane (B) analogues and binding affinity constant ($p[Od.]_{50}$) for porcine odorant-binding protein (pOBP) as receptor of pig pheromones were derived and disscused. The statistical quality of the optimized 2D-QSAR model is good ($r^{2}=0.964$) and accounts for 96.4% of the variance in the binding affinity constants. It was found that the binding affinity constants were dependent upon the optimal value, $(SL)_{opt.}=1.418$ of substituent lipole (SL) in molecules. Therefore, the SL constant was very important factor for binding affinity.

• Molecules and Cells
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• v.26 no.6
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• pp.558-565
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• 2008

Although the fertilizing ability of spermatozoa is greatly reduced after freezing, complete understanding of alterations induced by cryopreservation has not been elucidated. The present study evaluates the effects of cryopreservation on the $Ca^{2+}$ handling of boar spermatozoa using several sperm activators. Intracellular $Ca^{2+}$ signals from single spermatozoa were measured using confocal $Ca^{2+}$ imaging of unfrozen samples and of other spermatozoa after having been frozen. Elevation of the external $K^{2+}$ concentration elicited a three times larger $Ca^{2+}$ increase in fresh spermatozoa than in cryopreserved spermatozoa. Caffeine elicited $Ca^{2+}$ transients with some oscillations in the fresh spermatozoa, but not in the thawed spermatozoa. Depletion of the $Ca^{2+}$ store with thapsigargin induced a rapid rise in $Ca^{2+}$ in the control but generated a smaller increase of $Ca^{2+}$ after thawing. Exposure to progesterone induced a biphasic rise of the $Ca^{2+}$ level in the fresh spermatozoa only. Sperm viability was reduced by cryopreservation. Resting $Ca^{2+}$ levels in fresh and cryopreserved spermatozoa were similar. Longer incubation (2.5 h) of thawed spermatozoa partly recovered the $Ca^{2+}$ response to the interventions. These results suggest that cryopreservation reduces the responsiveness of spermatozoa to depolarization, modulators of the internal $Ca^{2+}$ store and progesterone in terms of the $Ca^{2+}$ signal, thus providing a possible mechanism for reduced fertility observed in cryopreserved boar spermatozoa.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.647-651
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• 2010

The advantages of the $CO_2$ laser are offset by the delay in laser wound healing secondary to thermal damage. To minimize the undesirable thermal damage of the $CO_2$ laser, investigators have developed technical advances in the delivery system of the laser energy. This study compared tissue healing of the continuous and the pulsed modes $CO_2$ laser wounds in an animal surgery model. Five healthy Landrace and Yorkshire mixed breeds of both genders were used (45-51 kg, 4-6 months old, three males and two females). A full thickness wound of skin ($2{\times}2{\times}2cm^2$) was made over on the each pig's both sides of dorsal midline at 0, 7, 14, and 18 days. The wounds created at 18, 14, 7 and 0 days were named post-wounding day (PWD) 3, 7, 14 and 21, respectively. In each pig, one wound (left side) was treated pulsed $CO_2$ laser and the other wound (right side) was treated continuous wave $CO_2$ laser. Each wound was closed with two interrupted suture of 3-0 sutures. At 21 days after initial wounding, each wound was taken for histological evaluations. The degrees of reepithelialization were performed more prominently in the pulsed mode group than in the continuous mode group. The degrees of granulation were greater significantly in pulsed mode group than those in the continuous mode on PWD 3 (p < 0.05). The degrees of fibroblasts in the pulsed mode group were greater significantly in comparison to those in the continuous mode group on PWD 7, (p < 0.05). In conclusion, reepithelialization, granulation and fibroblasts in the pulsed mode group were greater markedly in comparison to those in the continuous mode group. It was considered that pulsed mode $CO_2$ laser was more suitable for the skin incision than the continuous mode $CO_2$ laser.

• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.227-236
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• 2020

In this study, we have developed 3D8 scFv transgenic pig (TG) by microinjection of fertilized one-cell pig zygotes (2.17%). The effect of 3D8 scFv TG on porcine reproductive and respiratory syndrome virus (PRRSV) resistance were evaluated through PRRSV VR2332 (1×103 TCID50/mL) challenge and transmission experiments. As a result, the average daily weight gain (ADWG) of TG increased compared to the wild type pigs (WT) in PRRSV challenge groups and the serum viremia levels of the TG was significantly lower than of WT on the 7 day and 21 day after infection, meaning that the viral shedding was suppressed by 3D8 scFv expression. These results suggest that the expression of 3D8 scFv in pig could suppress spreading of infected virus to pigs sharing a room.