• Clinical and Experimental Reproductive Medicine
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• v.36 no.2
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• pp.101-109
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• 2009

Objective: This study was carried out to analyze the amount of telomeric DNA and telomerase activity in early bovine embryos. Methods: The amount of telomeric DNA in early bovine embryos at the 8 cell, morula and blastocyst stages was analyzed by Quantitative Fluorescence In Situ Hybridization (Q-FISH) technique using a bovine telomeric DNA probe. Telomerase activity was analyzed by Telomeric Repeat Amplification Protocol (TRAP assay). Results: The relative amount of telomeric DNA in early bovine embryos was gradually increased from 8 cell to blastocyst stage. It was not significantly associated with the grade of embryo quality. While telomerase activity was detected in the early bovine embryos at these stages, it significantly increased at morula stage and showed maximum activity at the blastocyst stage. Conclusion: The amount of telomeric DNA and the telomerase activity of bovine embryos increase during the progression of early embryogenesis, suggesting a positive correlation between telomeric DNA and telomerase activity. The telomerase activity seems to increase to maintain the levels of telomeric DNA through embryo development which are required for extensive cell division.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.547-554
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• 2004

Telomeres are nucleoprotein structures at the ends of chromosomes consisting of tandem repeat sequences of . (TTAGGG)n. Telomeres serve as guardians of the genome, protect individual chromosomes within the nucleus, and help in meiotic pairing of homologous chromosomes. To investigate the telomere distributions of cattle and pig chromosomes, fluorescence in situ hybridization(FISH) was carried out on metaphase spreads of in vitro fibroblast cultures from Holstein and Landrace using a human telomeric DNA repeat probe. Results indicate that the distinct double spots on both ends of chromosomes of cattle and pigs were observed. In cattle, there was a random variation in the intensity of telomere signals among chromosomes. In pigs, an interstitial telomeric signal was observed on the chromosome 6q1 of all the cells examined. According to quantitative fluorescence in situ hybridization(Q-FISH) analysis, some chromosomes had consistently much more telorneres at one end of chromosomes. In general, both species had consistently much more telomeres at q-end than p-end on most of chromosomes. The relative amount of telomeres on bovine chromosomes was higher than that on pig chromosomes. In additions, Y chromosome had the highest relative amount of telorneres in cattle and pigs.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.465-474
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• 2008

The amount of telomeric DNA was quantified across different breeds(Landrace, Duroc, Yorkshire and Berksire), at different ages(90 days old and 180 days old) and among sexes(male and female) in pigs raised at the Performance Testing Station of Korea Swine Association, Jinkyo, Korea. The telomeric DNA amount was quantified by Quantitative Fluorescence In Situ Hybridization(Q-FISH) using a porcine telomeric DNA probe on interphase nuclei of lymphocytes. Analysis revealed that the amount of telomeric DNA on the pig lymphocytes was found to decrease with age. The quantity of telomeres significantly differed among breeds at 90 days of age. The colored breeds such as Berkshire and Duroc had higher amount of telomeric DNA than the Yorkshire and Landrace breed. In addition, the amount of telomeric DNA in male lymphocytes was significantly higher than that of females. In the correlation coefficients between the telomere quantity and their productive traits; average daily gain, loin percent and index value were positively correlated, whereas body length, feed efficiency and back fat thickness correlated negatively. However, the correlation coefficients were very low and not significant. Therefore, this study suggests that the amount of telomeres on lymphocytes can be considered as a physiological marker but not as a productive marker in pig.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.13-15
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• 2004

Telomeres are the end of chromosomes and consist of a tandem repeat sequence of (TTAGGG)n and associated proteins. Telomeres are essential for chromosome stability and are related with cell senescence and apoptosis. This study was carried out to analyze the amount of telomeric DNA of chicken lymphocytes, which is to considered as bio-marker. The amount of telomeric DNA of lymphocytes in Korean Native Chicken and White Leghorn was analyzed by quantitative-fluorescence in situ hybridization (Q-FISH) technique using the chicken telomeric DNA probe. Telomere quantifies were compared among breeds, ages and sex, and the relationship between the amount of telomeres and their productive trait was also analyzed. Comparing the amount of telomeric DNA on lymphocytes during growing period, the amount of telomeres was gradually decreased as growing older. The telomere quantity was also significantly different in breeds and sex. Estimating correlation coefficient, the amount of telomeres was positively correlated to sexual maturity and body weight but negatively correlated to hen day egg production and egg weight. These results implicate the telomere quantity is considered as an individual bio-marker.

• Korean Journal of Poultry Science
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• v.37 no.3
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• pp.247-253
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• 2010

Telomeres are nucleoprotein structures at the ends of chromosomes consisting of DNA sequences arranged in tandemly repeated units $(TTAGGG)_n$. However, this hexamers can also occur at non-telomeric sites in some avians and vertbrate. This study was carried out to present the distribution of telomeric DNA sequences in Korean Native Chicken chromosomes. The fluorescence in situ hybridization technique using a telomeric DNA probe was performed to the metaphase spreads of chicken early embryonic cells. Telomeric DNA signals were detected at the ends of chromosomes including macrochromosomes and microchromosomes. In chicken, surprisingly, chromosome 1 showed very distinct interstitial telomeric DNA hybridization patterns which located two interstitial sites in the p-arm at 1p11 and 1p23, and one in the q-arm at 1q32. In chromosome number 2 and 3 also displayed interstitial telomeric signals (ITS) in the long arms at 2q24 and 3q32, respectively. The pattern of telomeric DNA distribution in Korean Native Chicken chromosomes was in agreement with a previously reported in Gallus domesticus. The relative amount of telomeric DNA sequences in each macrochromosomes ranged from 4.6% to 16.3%. Distribution of telomeric DNAs at the end of p-arm was much more than that of q-arm in almost chicken chromosomes. The distribution of ITS in chicken chromsomes implicate to tandem chromosome fusions that might have occurred during the process of karyotype evolution.

• Korean Journal of Poultry Science
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• v.40 no.1
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• pp.31-40
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• 2013

This study was performed to investigate the investigated effects of dietary supplementation of vitamin C and E on the growth performance and stress response in broiler chickens. Stress response was analyzed by the quantity of telomeric DNA, the rate of DNA damage and the expression levels of heat shock proteins (HSPs) and hydroxyl-3-methyl-glutaryl coenzyme A reductase (HMGCR) genes on tissues and blood. The telomere length and telomere shortening rates were analyzed by quantitative fluorescence in situ hybridization on the nuclei of lymphocytes and tissues. The DNA damage rate of lymphocytes was quantified by the comet assay. The expression levels of HSP70, HSP90s and HMGCR genes were measured by quantitative real-time polymerase chain reaction in lymphocytes. In results, there was no significant difference among treatments in body weight, weight gain, feed intake and mortality. The telomere shortening rate of the lymphocytes was significantly lower in the vitamin E supplemented group than the control group. The DNA damage was also decreased supplemented with vitamin C and E, as compared to the control group. The vitamin E supplemented group had a significant positive effect on the expressions of HMGCR, HSP90-${\alpha}$ and HSP90-${\beta}$ in lymphocytes, but had no significance on HSP70, as compared to the control group. We concluded that the dietary supplementation of vitamin E (100 mg/kg feed) had reduced the individual physiological stress response without stunt growth in broiler chickens.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.305-313
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• 2011

This study was conducted to investigate the effects of housing systems on the productivity and physiological response as stress indicators in White Leghorn chickens. The chickens subjected to the conventional cages had a significantly lower viability, hen-housed egg production, egg weight and body weight compared with those to the floor pens. However, the hens housed in the conventional cages had a shorter day of the first egg and a greater egg quality compared with those housed in the floor pens. In addition, this study was also investigated to identify biological markers for assessing the physiological response of chickens under stress conditions. As biological markers, the amount of telomeric DNA was analyzed by quantitative fluorescent in situ hybridization on the nuclei of cells. The DNA damage rate of lymphocytes was also quantified by the comet assay. The amount of telomeric DNA of the lymphocytes, kidney and spleen was significantly higher in the chickens under floor pens than those under conventional cages. The DNA damage also increased in chickens raised under conventional cages, as compared to the chickens under floor pens. As results, we conclude that the chickens housed in conventional cages have a greater stressful status than those housed in floor pens.

• Korean Journal of Poultry Science
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• v.36 no.4
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• pp.293-300
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• 2009

The rate of fetus with abnormal chromosomes increase with maternal age. Nondisjunction of aging oocyte chromosome is a major reason for the increased rate of abnormalities. Telomeres are the ends of eukaryotic chromosome, which are essential for chromosome stability and are related in cell senescence. This study was carried out to analyze the chromosome aberration rate and amount of telomeric DNA in chick embryo along with maternal age. Fertilized eggs and blood were sampled from White Leghorn layers starting at 20 weeks through to 70 weeks age at 10 weeks interval. Chromosome aberration rate was analyzed by karyotyping. The amounts of telomeric DNA in embryonic cells and lymphocytes were quantified by Quantitative Fluorescence in situ Hybridization method. The chromosome aberration rate in chick embryos significantly differed with maternal age. The chromosome aberration rate increased at early laying period and beyond 70 weeks of maternal age. Therefore, chromosome aberration rate was affected by maternal age due to ovulated oocytes state. However, the amount of telomeric DNA on embryonic cells did not differ significantly with maternal age. Thus, maternal age does not affects telomere quantity in their embryos due to cellular reprograming at early embryonic stage after fertilization.

• Korean Journal of Poultry Science
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• v.41 no.3
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• pp.217-225
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• 2014

Telomeres are the ends of the eukaryotic chromosomes and consist of a tandem repetitive DNA sequence and shelterin protein complex. The function of telomere is to protect chromosome. Telomere length in somatic cells tends to decrease with organismal age due to the end replication problem. However, several factors at the genetic, epigenetic and environmental level affect telomere length. In this study, we estimated heritability of telomere length and investigated inheritance of telomeres in a chicken. Telomere length of lymphocytes was analyzed by semi-quantitative polymerase chain reaction using telomere primer and quantitative fluorescence in situ hybridization using telomeric DNA probe. In results, heritability of telomere length was estimated 0.9 at birth by offspring-parent regression analysis and was estimated 0.03 and 0.04 at 10 and 30 weeks old, respectively, by parental variance analysis. There was a significant positive correlation in telomere length between father and their offspring (r=0.348), and mother and their offspring (r=0.380). In inheritance patterns of telomere length, the influence of paternal and maternal effect on their offspring was similar. The influence of inherited telomeres on male and female progeny was also roughly alike. These results implicated that imprinting of parental telomere length was regulated by autosomal genes, not sex linked genes. In addition, telomere length of offspring at birth did not differ along with their maternal age. Thus, maternal age does not affects telomere length in their offspring at birth owing to cellular reprogramming at early embryonic stage.

• Journal of Animal Science and Technology
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• v.50 no.4
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• pp.445-456
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• 2008

Telomeres consist of TTAGGG tandem repeated DNA sequences with specific proteins and locate at chromosome ends. Telomeres are essential for chromosome stability and are related with cell senescence, apoptosis and cancer. Telomerase is a ribonucleoprotein which has a template for the synthesis of telomeric DNA. This study was carried out to analyze the amount of telomeric DNA and telomerase activity in cattle cells. Analysis of the quantity of telomere in lymphocytes was done at different ages, sex and among Korean cattle and Holstein breeds. The telomerase activity was also analyzed in liver, brain, heart, kidney, and testis tissues of fetal calf and of 18 month old cattle. The amount of telomeres in lymphocytes and other tissue cells was analyzed by Quantitative-Fluorescence in situ Hybridization (Q-FISH) technique using a telomeric DNA probe. Telomerase activity was analyzed by Telomeric Repeat Amplification Protocol assay (TRAP). The amount of telomeric DNA on the lymphocytes during the whole life span was decreased along with age. Quantity of telomeres in Korean cattle was significantly higher than that in Holstein breed. The amount of telomeric DNA in males was significantly higher than that in females. Telomerase activity was up-regulated in most bovine tissues during fetal stage, but was down-regulated in most tissues at mature 18 month age except the testis cells. This study indicates that the amount of telomeres and telomerase activity of cells can be used as an age marker or/and a physiological marker of cattle.