Erratum to: Evaluation of adenosine triphosphate testing for on-farm cleanliness monitoring compared to microbiological testing in an empty pig farrowing unit.

[This corrects the article DOI: 10.5187/jast.2020.62.5.682.].

Multilocus Genotyping of Giardia duodenalis Occurring in Korean Native Calves.

Giardia duodenalis is one of the most widely occurring zoonotic protozoan parasites causing diarrheal disease in calves. This study aimed to investigate the prevalence of G. duodenalis in Korean native calves and elucidate the causal factors associated with giardiasis in these animals. We investigated the sequences of three genes (ssu, bg, and gdh) of G. duodenalis in fecal samples collected from 792 Korean native calves during 2019-2020. Data were analyzed with regard to age, sex, sampling season, and the fecal sample type (based on its physical characteristics). The samples were screened for the three genes mentioned above, and 44 samples (5.6%) were G. duodenalis-positive. Polymerase chain reaction results showed a significantly higher prevalence of the infection in calves aged ≥1 month and in those with watery diarrhea in spring season. Screening for the gene sequences ssu (87.5%), bg (96.2%), and gdh (96.7%) revealed that most of the G. duodenalis-positive samples belonged to assemblage E. Four of the G. duodenalis-positive samples belonged to the zoonotic assemblage A. This study highlights the importance of continuous surveillance of genetic mutations in G. duodenalis for the detection of emerging variants of zoonotic G. duodenalis in calves.

Effect of commercially purified deoxynivalenol and zearalenone mycotoxins on microbial diversity of pig cecum contents.

OBJECTIVE: Deoxynivalenol (DON) and zearalenone (ZEN) are mycotoxins that frequently contaminate maize and grain cereals, imposing risks to the health of both humans and animals and leading to economic losses. The gut microbiome has been shown to help combat the effects of such toxins, with certain microorganisms reported to contribute significantly to the detoxification process. METHODS: We examined the cecum contents of three different dietary groups of pigs (control, as well as diets contaminated with 8 mg DON/kg feed or 0.8 mg ZEN/kg feed). Bacterial 16S rRNA gene amplicons were acquired from the cecum contents and evaluated by next-generation sequencing. RESULTS: A total of 2,539,288 sequences were generated with ~500 nucleotide read lengths. Firmicutes, Bacteroidetes, and Proteobacteria were the dominant phyla, occupying more than 96% of all three groups. Lactobacillus, Bacteroides, Megasphaera, and Campylobacter showed potential as biomarkers for each group. Particularly, Lactobacillus and Bacteroides were more abundant in the DON and ZEN groups than in the control. Additionally, 52,414 operational taxonomic units were detected in the three groups; those of Bacteroides, Lactobacillus, Campylobacter, and Prevotella were most dominant and significantly varied between groups. Hence, contamination of feed by DON and ZEN affected the cecum microbiota, while Lactobacillus and Bacteroides were highly abundant and positively influenced the host physiology. CONCLUSION: Lactobacillus and Bacteroides play key roles in the process of detoxification and improving the immune response. We, therefore, believe that these results may be useful for determining whether disturbances in the intestinal microflora, such as the toxic effects of DON and ZEN, can be treated by modulating the intestinal bacterial flora.

Evaluation of adenosine triphosphate testing for on-farm cleanliness monitoring compared to microbiological testing in an empty pig farrowing unit.

Careful cleaning and disinfection of pigpens is essential to prevent disease spread and avoid the resultant economic losses. Hygiene in pigpens is generally evaluated by visual monitoring supplemented with bacteriological monitoring, which includes counting the total aerobic bacteria (TAB) and/or fecal indicator bacteria (FIB). However, these methods present drawbacks such as time and labor requirements. As adenosine triphosphate (ATP) is ubiquitous in all living organisms including microorganisms, this study aimed to directly compare the results of microbial assessment and ATP quantification, and to suggest possible detailed application methods of the ATP test for hygiene evaluation in pigpens of a farrowing unit. Before and after standard cleaning procedures, samples were collected from the floor corner, floor center, and feeding trough of four pigpens at different time points. No FIB were detected and both the TAB and ATP levels were significantly decreased in the floor center area after cleaning. FIB were continuously detected after cleaning and disinfection of the floor corners, and there was no significant ATP level reduction. The feeding trough did not show any significant difference in these values before and after cleaning, indicating insufficient cleaning of this area. The levels of TAB and ATP after cleaning were significantly correlated and the average ATP value was significantly lower in the absence of FIB than in their presence. In the absence of standard references, a more thorough hygiene management could be achieved evenly by supplementing cleaning or disinfection based on the lowest ATP results obtained at the cleanest test site, which in the present study was the floor center. Overall, these results indicate that the on-farm ATP test can be used to determine the cleanliness status, in addition to visual inspection, as an alternative to laboratory culture-based testing for the presence of microorganisms.

A sampling and estimation method for monitoring poultry red mite (Dermanyssus gallinae) infestation on caged-layer poultry farms.

BACKGROUND: The poultry red mite, Dermanyssus gallinae, is a serious problem in the laying hen industry worldwide. Currently, the foremost control method for D. gallinae is the implementation of integrated pest management, the effective application of which necessitates a precise monitoring method. OBJECTIVES: The aim of the study was to propose an accurate monitoring method with a reliable protocol for caged-layer poultry farms, and to suggest an objective classification for assessing D. gallinae infestation on caged-layer poultry farms according to the number of mites collected using the developed monitoring method. METHODS: We compared the numbers of mites collected from corrugated cardboard traps, regarding with length of sampling periods, sampling sites on cage, and sampling positions in farm buildings. The study also compared the mean numbers of mites collected by the developed method with the infestation levels using by the conventional monitoring methods in 37 caged-layer farm buildings. RESULTS: The statistical validation provided the suitable monitoring method that the traps were installed for 2 days on feed boxes at 27 sampling points which included three vertical levels across nine equally divided zones of farms. Using this monitoring method, the D. gallinae infestation level can be assessed objectively on caged-layer poultry farms. Moreover, the method is more sensitive than the conventional method in detecting very small populations of mites. CONCLUSIONS: This method can be used to identify the initial stages of D. gallinae infestation in the caged-layer poultry farms, and therefore, will contribute to establishment of effective control strategies for this mite.

Major medical causes by breed and life stage for dogs presented at veterinary clinics in the Republic of Korea: a survey of electronic medical records.

BACKGROUND: Age and breed are considered the greatest risk factors for disease prevalence and mortality in companion dogs. Understanding the prevalence of diseases, in relation to age and breed, would support appropriate guidance for future health care strategies and provide useful information for the early diagnosis of diseases. The purpose of this study was to investigate the major medical causes for dogs visiting primary-care veterinary clinics in the Republic of Korea, stratified by age and breed. METHODS: A total of 15,531 medical records of canine patients were analyzed from 11 veterinary clinics who shared data from January 1, 2016 to December 31, 2016. An electronic medical record (EMR) system was used for data collection, which included the animal identification number, age, breed, gender, neuter status, clinical information, and diagnosis. EMR data were classified using the International Classification of Disease system from the World Health Organization; presenting signs or diagnoses were identified according to breed and life stage. RESULTS: Within the age groups, preventive medicine (16.7% confidence intervals (CI) [15.9-17.5]) was the most common cause for clinic visits for the <1 year and 1-3 year groups. Additionally, neutering surgery (6.6% CI [6.0-7.1]) and patella luxation (1.4% CI [1.8-2.7]) were frequently performed in these age groups. In the 4-6 year group, otitis externa (8.8% CI [7.8-10.0]) and dermatitis or eczema (8.5% CI [7.5-9.6]) were common medical problems. In older dogs (>10 year), the prevalences of heart disease, kidney disease, Cushing's disease, and mammary tumors were higher than in the other age groups. Small and toy breed dogs comprised 67.7% of all dogs in this analysis. For all breeds, otitis externa, dermatitis or eczema, vomiting, and diarrhea were common medical problems. DISCUSSION: This study identified the most common medical disorders and differences in prevalences of diseases, according to age and breeds. The information from EMRs for dogs visiting primary-care veterinary clinics can provide background knowledge that is required to enable a better understanding of disease patterns and occurrence by age and breeds. The information from this study could enable the creation of strategies for preventing diseases and enable the identification of health problems for more effective disease management in companion dogs.

Deoxynivalenol- and zearalenone-contaminated feeds alter gene expression profiles in the livers of piglets.

OBJECTIVE: The Fusarium mycotoxins of deoxynivalenol (DON) and zerolenone (ZEN) cause health hazards for both humans and farm animals. Therefore, the main intention of this study was to reveal DON and ZEN effects on the mRNA expression of pro-inflammatory cytokines and other immune related genes in the liver of piglets. METHODS: In the present study, 15 six-week-old piglets were randomly assigned to the following three different dietary treatments for 4 weeks: control diet, diet containing 8 mg DON/kg feed, and diet containing 0.8 mg ZEN/kg feed. After 4 weeks, liver samples were collected and sequenced using RNA-Seq to investigate the effects of the mycotoxins on genes and gene networks associated with the immune systems of the piglets. RESULTS: Our analysis identified a total of 249 differentially expressed genes (DEGs), which included 99 upregulated and 150 downregulated genes in both the DON and ZEN dietary treatment groups. After biological pathway analysis, the DEGs were determined to be significantly enriched in gene ontology terms associated with many biological pathways, including immune response and cellular and metabolic processes. Consistent with inflammatory stimulation due to the mycotoxin-contaminated diet, the following Kyoto encyclopedia of genes and genomes pathways, which were related to disease and immune responses, were found to be enriched in the DEGs: allograft rejection pathway, cell adhesion molecules, graft-versus-host disease, autoimmune thyroid disease (AITD), type I diabetes mellitus, human T-cell leukemia lymphoma virus infection, and viral carcinogenesis. Genome-wide expression analysis revealed that DON and ZEN treatments downregulated the expression of the majority of the DEGs that were associated with inflammatory cytokines (interleukin 10 receptor, beta, chemokine [C-X-C motif] ligand 9), proliferation (insulin-like growth factor 1, major facilitator superfamily domain containing 2A, insulin-like growth factor binding protein 2, lipase G, and salt inducible kinase 1), and other immune response networks (paired immunoglobulin-like type 2 receptor beta, Src-like-adaptor-1 [SLA1], SLA3, SLA5, SLA7, claudin 4, nicotinamide N-methyltransferase, thyrotropin-releasing hormone degrading enzyme, ubiquitin D, histone H2B type 1, and serum amyloid A). CONCLUSION: In summary, our results demonstrated that high concentrations DON and ZEN disrupt immune-related processes in the liver.

Relationship between Sloan-Kettering virus expression and mammalian follicular development.

Sloan-Kettering virus gene, a product of a cellular proto-oncogene c-Ski is a unique nuclear pro-oncoprotein and belongs to the Ski/Sno proto-oncogene family. The aim of the present study was to locate Ski protein in rat ovaries in order to find insights into the possible involvement of Ski in follicular development. First, expression of c-Ski mRNA in the ovaries of adult female rats was confirmed by RT-PCR. Then, ovaries obtained on the day of estrus were subjected to immunohistochemical analysis for Ski and proliferating cell nuclear antigen (PCNA) in combination with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). RT-PCR and in situ hybridization revealed that c-Ski mRNA was expressed in the ovaries of the adult rat on the day of estrous and localized mainly in the granulose cells. Ski was expressed in granulosa cells that were positive for TUNEL, but negative for PCNA, regardless of the shape and size of follicles. Expression of Ski in TUNEL-positive granulosa cells, but not in PCNA-positive granulosa cells, was also verified in rats having atretic follicles with double staining. These results indicate that Ski is profoundly expressed in the granulosa cells of atretic follicles, but not in growing follicles. Based on the present findings, Ski may play a role in the apoptosis of granulosa cells during follicular atresia.

Dual effects of fluoxetine on mouse early embryonic development.

Fluoxetine, a selective serotonin reuptake inhibitor, regulates a variety of physiological processes, such as cell proliferation and apoptosis, in mammalian cells. Little is known about the role of fluoxetine in early embryonic development. This study was undertaken to investigate the effect of fluoxetine during mouse early embryonic development. Late two-cell stage embryos (2-cells) were cultured in the presence of various concentrations of fluoxetine (1 to 50µM) for different durations. When late 2-cells were incubated with 5µM fluoxetine for 6h, the percentage that developed into blastocysts increased compared to the control value. However, late 2-cells exposed to fluoxetine (5µM) over 24h showed a reduction in blastocyst formation. The addition of fluoxetine (5µM) together with KN93 or KN62 (calcium/calmodulin-dependent protein kinase II (CaMKII) inhibitors) failed to increase blastocyst formation. Fluoxetine treatment inhibited TREK-1 and TREK-2, members of the two-pore domain K(+) channel family expressed in mouse embryos, activities, indicating that fluoxetine-induced membrane depolarization in late 2-cells might have resulted from TREK inhibition. In addition, long-term exposure to fluoxetine altered the TREK mRNA expression levels. Furthermore, injection of siRNA targeting TREKs significantly decreased blastocyst formation by ~30% compared to injection of scrambled siRNA. Long-term exposure of fluoxetine had no effect on blastocyst formation of TREK deficient embryos. These results indicate that low-dose and short-term exposures of late 2-cells to fluoxetine probably increase blastocyst formation through activation of CaMKII-dependent signal transduction pathways, whereas long-term exposure decreases mouse early embryonic development through inhibition of TREK channel gating.

K(+) efflux through two-pore domain K(+) channels is required for mouse embryonic development.

Numerous studies have suggested that K(+) channels regulate a wide range of physiological processes in mammalian cells. However, little is known about the specific function of K(+) channels in germ cells. In this study, mouse zygotes were cultured in a medium containing K(+) channel blockers to identify the functional role of K(+) channels in mouse embryonic development. Voltage-dependent K(+) channel blockers, such as tetraethylammonium and BaCl(2), had no effect on embryonic development to the blastocyst stage, whereas K(2P) channel blockers, such as quinine, selective serotonin reuptake inhibitors (fluoxetine, paroxetine, and citalopram), gadolinium trichloride, anandamide, ruthenium red, and zinc chloride, significantly decreased blastocyst formation (P<0.05). RT-PCR data showed that members of the K(2P) channel family, specifically KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9, were expressed in mouse oocytes and embryos. In addition, their mRNA expression levels, except Kcnk3, were up-regulated by above ninefold in morula-stage embryos compared with 2-cell stage embryos (2-cells). Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed in the membrane of oocytes, 2-cells, and blastocysts. Each siRNA injection targeted at Kcnk2, Kcnk10, Kcnk4, Kcnk3, and Kcnk9 significantly decreased blastocyst formation by ~38% compared with scrambled siRNA injection (P<0.05). The blockade of K(2P) channels acidified the intracellular pH and depolarized the membrane potential. These results suggest that K(2P) channels could improve mouse embryonic development through the modulation of gating by activators.

Acetylcholine controls mouse oocyte maturation via downregulation of cAMP.

1. In mice, acetylcholine (ACh) plays an important role in oocyte activation and embryonic development. However, the role of ACh in mouse oocyte maturation has not been investigated. 2. In the present study, the effects of 100 µmol/L and 1 mmol/L ACh on maturation processes of murine germinal vesicle (GV) intact oocytes (GV oocytes) exposed to 10 and 100 µmol/L 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of cyclic nucleotide phosphodiesterase, were evaluated morphologically and immunologically. It has been shown that IBMX inhibits the resumption of meiosis by preventing cAMP breakdown. 3. In the present study, at the start of in vitro culture 100% of oocytes were at the GV stage. After 18 h culture, 95 ± 3, 0 and 85.8 ± 10.2% of oocytes had passed the GV stage in the control, IBMX and IBMX + ACh groups, respectively. The IBMX-induced inhibition of the maturation process was significantly attenuated by approximately 90% by ACh in groups treated with 10 µmol/L IBMX + 100 µmol/L ACh and 100 µmol/L IBMX + 1 mmol/L ACh. Although cAMP levels were high in oocytes treated with 100 µmol/L IBMX, levels were reduced in groups treated simultaneously with 100 µmol/L ACh. Furthermore, compared with mature oocytes, ACh-treated GV oocytes exhibited significantly lower (by approximately 2.3-fold) or absent Ca(2+) peaks. 4. The results of the present study indicate that maturation of GV oocytes, arrested by IBMX treatment, is resumed following ACh treatment and that this effect is due to downregulation of cAMP rather than changes in intracellular Ca(2+) levels.

Identification of differentially expressed genes in bovine follicular cystic ovaries.

Follicular cystic ovary (FCO) is one of the most frequently diagnosed ovarian diseases and is a major cause of reproductive failure in mammalian species. However, the mechanism by which FCO is induced remains unclear. Genetic alterations which affect the functioning of many kinds of cells and/or tissues could be present in cystic ovaries. In this study, we performed a comparison analysis of gene expression in order to identify new molecules useful in discrimination of bovine FCO with follicular cystic follicles (FCFs). Normal follicles and FCFs were classified based on their sizes (5 to 10 mm and ≥25 mm). These follicles had granulosa cell layer and theca interna and the hormone 17ß-estradiol (E(2))/ progesterone (P(4)) ratio in follicles was greater than one. Perifollicular regions including follicles were used for the preparation of RNA or protein. Differentially expressed genes (DEG) that showed greater than a 2-fold change in expression were screened by the annealing control primer (ACP)-based PCR method using GeneFishing™ DEG kits in bovine normal follicles and FCFs. We identified two DEGs in the FCFs: ribosomal protein L15 (RPL15) and microtubule-associated protein 1B (MAP1B) based on BLAST searches of the NCBI GenBank. Consistent with the ACP analysis, semi-quantitative PCR data and Western blot analyses revealed an up-regulation of RPL15 and a down-regulation of MAP1B in FCFs. These results suggest that RPL15 and MAP1B may be involved in the regulation of pathological processes in bovine FCOs and may help to establish a bovine gene data-base for the discrimination of FCOs from normal ovaries.

Proteomic analysis of differentially expressed proteins in bovine endometrium with endometritis.

Endometritis is one of the primary reasons for reproductive failure. In order to investigate endometritis-associated marker proteins, proteomic analysis was performed on bovine endometrium with endometritis. In bovine endometritis, desmin, α-actin-2, heat-shock protein (HSP) 27, peroxiredoxin-6, luteinizing hormone receptor isoform 1, collectin-43 precursor, deoxyribonuclease-I (DNase-I), and MHC class I heavy chain (MHC-Ih) were up-regulated. In contrast, transferrin, interleukin-2 precursor, hemoglobin ß subunit, and potassium channel tetramerisation domain-containing 11 (KCTD11) were down-regulated in comparison to normal endometrium. The proteomic results were validated by semiquantitative-PCR and immunoblot analysis. The mRNA levels of desmin, transferrin, α-actin-2, HSP27, KCTD11, and MHC-Ih were up-regulated by over 1.5-fold, and showed a pattern similar to their proteomic profiles. Desmin and α-actin-2 protein showed positive correlations between proteomic analysis and immunoblot analysis. These results suggest that desmin and α-actin-2 may play important roles in endometritis-related function, and could be useful markers for the diagnosis of bovine endometritis.

Synergistic effects of glutathione and ß-mercaptoethanol treatment during in vitro maturation of porcine oocytes on early embryonic development in a culture system supplemented with L-cysteine.

Various methods have been used to remove reactive oxygen species (ROS) generated from in vitro culture (IVC) conditions that can cause cell injury or death, including the application of low oxygen (O(2)) tension and the addition of antioxidants. The beneficial effects of antioxidants and O(2) tension on IVC of porcine embryos, however, are controversial among researchers. In this study, we sought to determine the effects and optimal concentrations of antioxidants for the development of porcine embryos in an IVC system. Specifically, we examined the synergistic effects of antioxidants on development to the blastocyst stage in a culture system supplemented with L-cysteine during IVM. Of the antioxidants tested (melatonin, glutathione (GSH), ß-mercaptoethanol (ß-ME), N-acetylcysteine (NAC) and dithiothreitol (DTT)), addition of GSH (1 mM) or ß-ME (25 µM) significantly increased development to the blastocyst stage compared with the controls without antioxidant treatment (22.2 ± 4.2% for 1 mM GSH, 25.9 ± 2.2% for 25 µM ß-ME and 12-13% for the control, P<0.05). In addition, the mean cell number per blastocyst was increased by approximately 1.7-fold in the presence of GSH or ß -ME. These GSH- and ß-ME-induced increases in development to the blastocyst stage and total cell number, however, were not mimicked by melatonin, NAC or DTT, all of which are ROS scavengers. The combination of GSH or ß-ME with L-cysteine significantly reduced high O(2) tension-induced ROS production (P<0.05). These results suggest that a combination of 1 mM GSH or 25 µM ß-ME with 1 mM L-cysteine could be used for production of high quality porcine blastocysts in IVC systems.

Acetylcholine rescues two-cell block through activation of IP3 receptors and Ca2+/calmodulin-dependent kinase II in an ICR mouse strain.

Acetylcholine (ACh) causes early activation events in mouse oocytes, but little is known about its precise role in the early embryonic development of mice. We aimed to determine whether and how ACh is capable of rescuing two-cell block in an in vitro culture system. ACh evoked different transient Ca(2+) patterns showing a higher Ca(2+) peak in the two-cell stage embryos (two-cells) than observed in mature oocytes. In early two-cells subjected to an in vitro two-cell block, xestospongin C (Xes-C), an IP3 receptor antagonist, significantly decreased the level of the ACh-induced Ca(2+) increase. The reduction in the ACh-induced Ca(2+) increase by Xes-C in late two-cells was lower than that in early two-cells. Furthermore, KN62 and KN93, both CaMKII inhibitors, were found to reduce the magnitude of the ACh-induced Ca(2+) increase in early two-cells. The addition of ACh to the culture medium showed an ability to rescue in vitro two-cell block. However, the addition of ACh together with both Xes-C and CaMKII inhibitors or with either inhibitor separately had no effect on the rescue of two-cell block. Long-term exposure of late two-cells to ACh decreased morula and early blastocyst development and ACh had a differential effect on early and late two-cells. These results indicate that ACh likely rescues the in vitro two-cell block through activation of IP3R- and/or CaMKII-dependent signal transduction pathways.

Expression and localization of two-pore domain K(+) channels in bovine germ cells.

Two-pore domain K(+) (K(2P)) channels that help set the resting membrane potential of excitable and nonexcitable cells are expressed in many kinds of cells and tissues. However, the expression of K(2P) channels has not yet been reported in bovine germ cells. In this study, we demonstrate for the first time that K(2P) channels are expressed in the reproductive organs and germ cells of Korean cattle. RT-PCR data showed that members of the K(2P) channel family, specifically KCNK3, KCNK9, KCNK2, KCNK10, and KCNK4, were expressed in the ovary, testis, oocytes, embryo, and sperm. Out of these channels, KCNK2 and KCNK4 mRNAs were abundantly expressed in the mature oocytes, eight-cell stage embryos, and blastocysts compared with immature oocytes. KCNK4 and KCNK3 were significantly increased in eight-cell stage embryos. Immunocytochemical data showed that KCNK2, KCNK10, KCNK4, KCNK3, and KCNK9 channel proteins were expressed at the membrane of oocytes and blastocysts. KCNK10 and KCNK4 were strongly expressed and distributed in oocyte membranes. These channel proteins were also localized to the acrosome sperm cap. In particular, KCNK3 and KCNK4 were strongly localized to the post-acrosomal region of the sperm head and the equatorial band within the sperm head respectively. These results suggest that K(2P) channels might contribute to the background K(+) conductance of germ cells and regulate various physiological processes, such as maturation, fertilization, and development.

A CIDR-based timed embryo transfer protocol increases the pregnancy rate of lactating repeat breeder dairy cows.

This study evaluated the pregnancy rates following either a controlled internal drug release (CIDR)-based timed artificial insemination (TAI) or an embryo transfer (TET) protocol compared with that following a single PGF(2alpha) injection and AI after estrus (AIE) in lactating repeat breeder dairy cows. Fifty-three lactating dairy cows diagnosed as repeat breeders were used in this study and were randomly assigned to the following three treatments. (1) Cows, at random stages of the estrous cycle, received a CIDR device and 2 mg estradiol benzoate (EB; Day 0), a 25 mg PGF(2) (alpha) injection at the time of CIDR removal on Day 7 and a 1 mg EB injection on Day 8. The cows then received TAI 30 h (Day 9) after the second EB injection using dairy semen (TAI group, n=13). (2) Cows, at random stages of the estrous cycle, received the same hormonal treatments as in the TAI group. The cows then received TET on Day 16 using frozen-thawed blastocysts or morula embryos collected from Korean native cattle donors (TET group, n=13). (3) Cows, at the luteal phase, received a 25 mg injection of PGF(2alpha) and AIE using dairy semen (control group, n=27). The ovaries of the cows in the TET group were examined by transrectal ultrasonography to determine ovulation of the preovulatory follicles, and blood samples were collected for serum progesterone (P4) analysis. The pregnancy rate was significantly higher in the TET group (53.8%) than in the control (18.5%) or TAI (7.7%) groups (P<0.05). The ultrasonographic observations demonstrated that all the cows in the TET group ovulated the preovulatory follicles and concomitantly formed new corpora lutea. Accordingly, the mean serum P4 concentration remained constant between Day 0 and Day 7 of the luteal phase, decreased dramatically on Day 8 (P<0.01) and subsequently increased by Day 16 (P<0.01). These data suggest that the CIDR-based TET protocol can be used to effectively increase the pregnancy rate in lactating repeat breeder dairy cows.

The effect of reduced dose and number of treatments of FSH on superovulatory response in CIDR-treated Korean native cows.

The objective of this study was to investigate the effect of dosage and number of days of follicle stimulating hormone (FSH) treatment on superovulatory response in controlled internal drug release (CIDR)-treated Korean native cows. Forty cows underwent two superovulatory treatments with a crossover design. Cows, at random stages of the estrous cycle, received a CIDR together with injections of 1 mg estradiol benzoate and 50 mg progesterone, and gonadotropin treatment began 4 days later. The cows were divided into 2 groups based on the dosage and number of days of treatment with porcine FSH; a total of 28 mg FSH was given in twice daily intramascular injections in decreasing doses over 4 days (5, 5, 4, 4, 3, 3, 2 and 2 mg; T1 group, n=20) or a total of 24 mg FSH was given in twice daily decreasing doses over 3 days (5, 5, 4, 4, 3 and 3 mg; T2 group, n=20). This was followed by the alternate treatment in the subsequent superovulation. The cows were treated identically in all other respects. PGF(2alpha) (25 mg and 15 mg) was given with the 5th and 6th injections of FSH, CIDR were withdrawn at the 6th FSH injection and the cows received 200 microg GnRH 36 h after CIDR withdrawal. The cows were artificially inseminated twice, at 48 and 60 h after CIDR withdrawal, using commercial semen from four Korean native bulls, and embryos were recovered 6 or 7 days after the 2nd insemination. The numbers of corpora lutea (CL; 7.9+/-1.0 vs. 8.3+/-1.1) and large follicles (1.2+/-0.2 vs. 1.3+/-0.3) present at the time embryo recovery, as detected by ultrasonography, did not differ between the T1 and T2 groups (P>0.05). Similarly, the numbers of total ova/embryos (6.2+/-0.9 vs. 6.4+/-1.1), transferable embryos (3.4+/-0.8 vs. 3.2+/-0.7), degenerate embryos (0.8+/-0.2 vs. 1.0+/-0.3) and unfertilized ova (2.1+/-0.5 vs. 2.2+/-0.5) did not differ between the groups (P>0.05). These data indicate that a reduced dose (24 vs. 28 mg) and number of treatments (6 vs. 8) of FSH for superovulation of CIDR-treated Korean native cows does not affect the embryo yield.

Properties of single two-pore domain TREK-2 channels expressed in mammalian cells.

TREK-2 (K2P10.1), a member of the two-pore domain K+ (K2P) channel family, provides the background K+ conductance in many cell types, and is a target of neurotransmitters that act on receptors coupled to Gs and Gq. We report here that TREK-2 exhibits small (TREK-2S) and large (TREK-2L) conductance phenotypes when expressed in mammalian cell lines (COS-7, HEK293, HeLa) and in Xenopus oocytes. TREK-2S phenotype shows a noisy open state with a mean conductance of 54 pS (+40 mV). TREK-2L phenotype shows a full open state (202 pS) with several short-lived sub-conductance levels. Both phenotypes were strongly activated by arachidonic acid, membrane stretch (-40 mmHg) and intracellular acidification (pH 6.4). Phosphorylation of TREK-2 produced by treatment of cells with activators of protein kinases A and C, and okadaic acid (a serine/threonine phosphatase inhibitor) decreased the current contributed by TREK-2S and TREK-2L, and caused partial switching of conductance levels from those of TREK-2S and TREK-2L to more intermediate values. Under this condition, TREK-2 exhibited six conducting levels and one closed level. TREK-2 mutants in which putative protein kinases A and C phosphorylation sites were mutated to alanines (S326A, S359A, S326A/S359A) displayed mostly TREK-2S and TREK-2L phenotypes. However, S326D and S359D mutants (as well as the double mutants) that mimic the phosphorylated state showed all six conducting levels and low channel activity. The S326A and S359A mutants did not significantly affect the intrinsic voltage dependence of TREK-2 in Mg2+-free solution. Phenotypes resembling TREK-2S and TREK-2L were also observed in cerebellar granule neurons that express TREK-2 mRNA. These results show that TREK-2 exhibits two primary modes of gating that give rise to two channel phenotypes under dephosphorylated conditions, and that its phosphorylation shifts the gating mode to include intermediate conducting levels. This represents a novel mechanism by which receptor agonists modulate the function of a K+ channel to alter cell excitability.

Effect of estradiol benzoate or GnRH treatment prior to superstimulation in CIDR-treated, Korean native cows (Bos taurus).

The objective of this study was to evaluate the effectiveness of superovulatory protocols by synchronizing the emergence of the follicular wave using estradiol benzoate (EB) or GnRH in CIDR-treated, Korean cows. Sixty-six cows were used in the study and these were divided into three groups. The standard group comprised cows that were between days 8 and 12 of their estrous cycle (n=22). The remaining 44 cows, at all other stages of the estrous cycle, received CIDR and were assigned to two treatment groups that received either 2mg EB (EB-CIDR group, n=22) or 100 microg GnRH (GnRH-CIDR group, n=22) 1 day after CIDR insertion. Gonadotropin treatment began between the 8th and 12th days of the estrous cycle in the standard group, 5 days after EB injection in the EB-CIDR group, and 3 days after GnRH injection in the GnRH-CIDR group. All cows were superovulated with porcine FSH (pFSH) twice daily, with the dose (total 28 mg) decreasing gradually over 4 days. On the 5th and 6th injections of pFSH, 25 and 15 mg doses of PGF(2alpha) were administered. CIDR was withdrawn at the 7th pFSH injection and the cows received 200 microg GnRH at 24h after CIDR withdrawal. Cows were artificially inseminated twice at 36 and 48 h post-CIDR withdrawal and embryos were recovered 7 days after the 1st insemination. The numbers of preovulatory follicles (22.9-28.2), ovulated preovulatory follicles (17.6-21.7) and CL (15.9-17.9) detected by ultrasonography did not differ among groups (P>0.05). Similarly, the numbers of total ova (6.7-10.0), transferable embryos (4.0-6.0), degenerate embryos (1.1-1.8) and unfertilized ova (1.3-4.3) did not differ among groups (P>0.05). Progesterone and estradiol concentrations during superovulation treatments and at embryo recovery were also the same in all groups (P>0.05). We conclude that in CIDR-treated Korean native cows, superovulatory treatments that follow administration of either EB or GnRH (at any stage of the estrous cycle) result in both a superovulatory response and embryo yield comparable to conventional superovulation protocols.