• Journal of Korean Biological Nursing Science
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• 제24권4호
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• pp.235-242
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• 2022

Purpose: To investigate associations of perceived stress level, serum cortisol level, and telomere length of community-dwelling adults in Korea. Methods: Data of a total of 135 community-dwelling adults aged over 40 years living in D metropolitan city from December 2020 to March 2021 were collected. Perceived stress level over the past month were measured using the Perceived Stress Score. Serum cortisol level was analyzed using a chemiluminescent microparticle immunoassay. Telomere length was determined using quantitative real-time polymerase chain reaction. The statistical package SPSS 23.0 was used to perform Chi-square test, independent t-test, and Pearson's correlation coefficient analysis. Results: There was no association between perceived stress and serum cortisol level (r = .07, p= .402). Serum cortisol level was not significantly associated with telomere length either (r = -.15, p= .081). However, the higher the perceived stress level, the shorter the telomere length (r= -.29, p= .001). Conclusion: These results suggest that perceived stress might induce physiological stress, which might partially affect gene biology. Further longitudinal research is needed to investigate the effect of perceived stress on telomere length. Intervention for relieving stress should be included in stabilizing the genetic environment of adults.

• 한국가금학회지
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• 제49권3호
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• pp.145-156
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• 2022

본 연구는 한국 토종닭을 대상으로 부계의 텔로미어 길이가 수정 능력 및 배아 발생 능력에 미치는 영향을 알아보고, 부계의 텔로미어 길이와 자식의 생산능력 및 자식의 텔로미어 길이와의 연관성을 살펴보고자 하였다. 시험에 공시된 닭은 토종 종계 수컷 22수와 이들로부터 생산된 자식 329수를 대상으로 하였다. 부계의 번식 능력으로는 수정율, 배자발육중지율 및 부화율을 조사하였고, 자손의 생산 능력으로는 생존율, 체중 및 증체량을 분석하였다. 텔로미어 길이는 34주령 부계와 12주령 자식의 백혈구 세포 내 telomeric DNA 함량을 양적 형광접합보인법으로 분석하였다. 분석 결과, 부계의 텔로미어 길이에 따른 수정율, 배자발육중지율 및 부화율의 차이는 없는 것으로 나타났고, 부계의 텔로미어 길이와 수정률 및 배자발육중지율 간에는 낮은 부(-)의 상관을, 부화율과는 낮은 정(+)의 상관을 보이나 이들의 상관계수는 유의하지 않은 것으로 나타났다(P>0.05). 부계의 텔로미어 길이와 자식의 생존율 간의 상관 계수는 0.17로 유의하지 않은 낮은 정의 상관이 추정되었다(P>0.05). 부계의 텔로미어 길이에 따른 자식의 성장 능력 분석에서 부계 텔로미어 길이가 긴 집단의 자식들이 상대적으로 낮은 성장 능력을 보이고 이들 간의 상관은 거의 모든 주령에서 유의한 부의 상관 계수가 추정되었다(P<0.05). 부계의 텔로미어 길이와 자식의 텔로미어 길이 간의 상관 계수는 0.075로 추정되어 부계와 자식 간 텔로미어 길이의 연관성이 없는 것으로 나타났다. 이상의 결과로부터 부계의 텔로미어 길이와 번식 능력, 자식의 초기 생존율 및 자식의 텔로미어 길이 간에는 거의 연관성이 없는 것으로 보여지고, 부계의 텔로미어 길이와 자식의 성장 능력 간에는 부의 상관이 있는 것으로 생각된다. 이는 배아 초기 단계에서 텔로미어의 reprogramming에 의해 발생 시 모든 개체의 텔로미어 길이가 재 신장되고 이후 연령이 증가함에 따라 감축의 정도가 달라지기 때문에 나타난 결과로 사료된다.

• 한국동물생명공학회지
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• 제34권2호
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• pp.93-99
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• 2019

Telomeres are known as a specialized region in the end of chromosomes to protect DNA destruction, but their lengths are shortened by repetition of cell division. This telomere shortening can be preserved or be elongated by telomerase and TERT expression. Although a certain condition in the cells may affect to the cellular and molecular characteristics, the effect of differentiation induction to telomere length and telomerase activity in mesenchymal stem cells (MSCs) has been less studied. Therefore, the present study aimed to uncover periodical alterations of telomere length, telomerase activity and TERT expression in the dental pulp-derived MSCs (DP-MSCs) under condition of differentiation inductions into adipocytes and osteoblasts on a weekly basis up to 3 weeks. Shortening of telomere was significantly (p < 0.05) identified from early-middle stages of both differentiations in comparison with undifferentiated DP-MSCs by non-radioactive chemiluminescent assay and qRT-PCR method. Telomere length in undifferentiated DP-MSCs was 10.5 kb, but the late stage of differentiated DP-MSCs which can be regarded as the adult somatic cell exhibited 8.1-8.6 kb. Furthermore, the relative-quantitative telomerase repeat amplification protocol or western blotting presented significant (p < 0.05) decrease of telomerase activity since early stages of differentiations or TERT expression from middle stages of differentiations than undifferentiated state, respectively. Based on these results, it is supposed that shortened telomere length in differentiated DP-MSCs was remained along with prolonged differentiation durations, possibly due to weakened telomerase activity and TERT expression. We expect that the present study contributes on understanding differentiation mechanism of MSCs, and provides standardizing therapeutic strategies in clinical application of MSCs in the animal biotechnology.

• 미생물학회지
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• 제52권1호
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• pp.116-119
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• 2016

텔로미어를 안정적으로 유지하는 것은 세포의 증식과 생존에 필수적이다. 비록 텔로미어 유지에는 telomerase가 가장 중요한 수단이지만 재조합도 텔로미어 유지를 위한 또 다른 중요한 과정으로 작용한다. 본 연구에서는 효모의 텔로미어 내부에 존재하는 $TG_{1-3}$ 반복서열을 이용하여 텔로미어 재조합을 관찰할 수 있는 유전학적 방법을 개발하였다. 관찰된 재조합 빈도는 내부 $TG_{1-3}$ 반복서열의 존재 여부에 영향을 받았으며, 생성된 $FOA^rCan^r$ 콜로니로부터 추출한 유전체 DNA를 사용하여 URA3와 CAN1 marker 근처 부위를 PCR 증폭한 결과, 각 콜로니들은 marker를 포함한 염색체 말단 부위가 결손 된 것으로 나타났다. 뿐만 아니라, 더 긴 내부 $TG_{1-3}$ 반복서열을 사용하였을 때 재조합 빈도는 더 증가하였다. 이러한 결과는 $FOA^rCan^r$ 콜로니 형성이 내부와 말단의 $TG_{1-3}$ 반복서열 사이의 재조합에 기인한다는 것을 의미한다.

• Tuberculosis and Respiratory Diseases
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• 제84권3호
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• pp.188-199
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• 2021

Background: Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with increased prevalence in the elderly. Telomeres are repetitive DNA sequences found at the end of the chromosome, which progressively shorten as cells divide. Telomere length is known to be a molecular marker of aging. This study aimed to assess the relationship between telomere length and the risk of COPD, lung function, respiratory symptoms, and emphysema index in Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) cohort. Methods: We extracted DNA from the peripheral blood samples of 446 participants, including 285 COPD patients and 161 control participants. We measured absolute telomere length using quantitative real-time polymerase chain reaction. All participants underwent spirometry and quantitative computed tomography scan. Questionnaires assessing respiratory symptoms and the COPD Assessment Test was filled by all the participants. Results: The mean age of participants at the baseline visit was 72.5±7.1 years. Males accounted for 72% (321 participants) of the all participants. The mean telomere length was lower in the COPD group compared to the non-COPD group (COPD, 16.81±13.90 kb; non-COPD, 21.97±14.43 kb). In COPD patients, 112 (75.7%) were distributed as tertile 1 (shortest), 91 (61.1%) as tertile 2 and 82 (55%) as tertile 3 (longest). We did not find significant associations between telomere length and lung function, exacerbation, airway wall thickness, and emphysema index after adjusting for sex, age, and smoking status. Conclusion: In this study, the relationship between various COPD phenotypes and telomere length was analyzed, but no significant statistical associations were shown.

• Nutrition Research and Practice
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• 제13권1호
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• pp.58-63
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• 2019

BACKGROUND/OBJECTIVES: Telomeres are located at the chromosomal ends and progressively shortened during each cell cycle. Telomerase, which is regulated by hTERT and c-MYC, maintains telomeric DNA sequences. Especially, telomerase is active in cancer and stem cells to maintain telomere length for replicative immortality. Recently we reported that walnut phenolic extract (WPE) can reduce cell viability in a colon cancer stem cell (CSC) model. We, therefore, investigated the effect of WPE on telomere maintenance in the same model. MATERIALS AND METHODS: $CD133^+CD44^+$ cells from HCT116, a human colon cancer cell line, were sorted by Fluorescence-activated cell sorting (FACS) and treated with WPE at the concentrations of 0, 10, 20, and $40{\mu}g/mL$ for 6 days. Telomere lengths were assessed by quantitative real-time PCR (qRT-PCR) using telomere specific primers and DNA extracted from the cells, which was further adjusted with single-copy gene and reference DNA ($ddC_t$). Telomerase activity was also measured by qRT-PCR after incubating the PCR mixture with cell protein extracts, which was adjusted with reference DNA ($dC_t$). Transcriptions of hTERT and c-MYC were determined using conventional RT-PCR. RESULTS: Telomere length of WPE-treated cells was significantly decreased in a dose-dependent manner ($5.16{\pm}0.13$ at $0{\mu}g/mL$, $4.79{\pm}0.12$ at $10{\mu}g/mL$, $3.24{\pm}0.08$ at $20{\mu}g/mL$ and $3.99{\pm}0.09$ at $40{\mu}g/mL$; P = 0.0276). Telomerase activities concurrently decreased with telomere length ($1.47{\pm}0.04$, $1.09{\pm}0.01$, $0.76{\pm}0.08$, and $0.88{\pm}0.06$; P = 0.0067). There was a positive correlation between telomere length and telomerase activity (r = 0.9090; P < 0.0001). Transcriptions of both hTERT and c-MYC were also significantly decreased in the same manner. CONCLUSION: In the present cell culture model, WPE reduced telomere maintenance, which may provide a mechanistic link to the effect of walnuts on the viability of colon CSCs.

• Journal of Animal Science and Technology
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• 제53권3호
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• pp.195-202
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• 2011

Maintenance of adequate telomere length in developing cells is the most important concern to preserve the integrity of the genome. The length of telomere is strictly regulated by numerous telomere-binding proteins and/or interacting factors. Even though the expression of telomerase in the male reproductive tract has been characterized, developmental expressional profiling of telomerase and other telomere-associated proteins has not been determined in detail. The present study was attempted to examine expression patterns of catalytic subunit (Tert) and RNA component (Terc) of telomerase and two telomerase associated factors, telomerase associated protein 1 (Tep1) and TERF1 (TRF1) interacting nuclear factor 2 (Tinf2) in the testis and seminal vesicle of male rat during postnatal development. The real-time PCR analysis was utilized to quantify mRNA expression of molecules. The abundance of Tep1 mRNA in the testis and seminal vesicle was the highest at 5 months of age. Expressional fluctuation of Tinf2 during postnatal development was found in the testis, while expression of Tinf2 in the seminal vesicle was gradually increased until 5 months of age and then significantly decreased later. mRNA level of Tert gene in the testis was significantly increased at the adult and the elder, while the highest expression of Tert gene in the seminal vesicle was found at 5 months of age. Expression of Terc transcript in the testis and seminal vesicle was the highest at 5 months of age, followed by significant reduction at 1 and 2 years of ages. Such differential gene expression of telomere-associated factors and telomerase components in different male reproductive tissues during postnatal development indicates that maintenance of telomere length would be regulated in tissue- and/or age-specific manners.

• Toxicological Research
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• 제19권3호
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• pp.161-172
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• 2003

Explanted mammalian cells perform a limited number of cell division in vitro and than are arrested in a state known as replicative senescence. Such cells are irreversibly blocked, mostly in the G1 phase of cell cycle, and are no longer sensitive to growth factor stimulation. Thus replicative senescence is defined as a permanent and irreversible loss of replicative potential of cells. For this characteristic, replicative senescence seems to evolve to protect mammalian organism from cancer. However, senescence also contributes to aging. It seems to decrease with age of the cell donor and, as a form of cell senescence, is thought to underlie the aging process. Extensive evidence supports the idea that progressive telomere loss contributes to the phenomenon of cell senescence. Telomeres are repetitive structures of the sequence (TTAGGG)n at the ends of linear chromosomes. It has been shown that the average length of telomere repeats in human somatic cells decreases by 30∼200 bp with each cell division. It is generally believed that when telomeres reach a critical length, a signal is activated to initiate the senescent program. This has given rise to the hypothesis that telomeres act as mitotic clocks to regulate lifespan. One proposes that cumulative oxidative stress, mainly reactive oxygen species generated from mitochondria, may mainly cause telomere shortening, accelerating aging. Here, the biological importance and mechanism of replicative senescence were briefly reviewed. Also it was summarized that how oxidative stress affects replicative senescence and telomere shortening.

• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.603-609
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• 2011

Telomeres are special structures at the ends of eukaryotic chromosomes. Vertebrate telomeres consist of tandem repeats of conserved TTAGGG sequence and associated proteins. Birds are interesting models for molecular studies on aging and cellular senescence because of their slow aging rates and longer life spans for their body size. In this longitudinal study, we explored the possibility of using telomeres as an age-marker to predict age in Single Comb White Leghorn layer chickens. We quantified the relative amount of telomeric DNA in isolated peripheral blood lymphocytes by the Quantitative Fluorescence in situ Hybridization technique on interphase nuclei (IQ FISH) using telomere-specific DNA probes. We found that the amount of telomeric DNA (ATD) reduced significantly with an increase in chronological age of the chicken. Especially, the telomere shortening rates are greatly increased in growing individuals compared to laying and old-aged individuals. Therefore, using the ATD values obtained by IQ FISH we established the possibility of age prediction in chickens based on the telomere theory of aging. By regression analysis of the ATD values at each age interval, we formulated an equation to predict the age of chickens. In conclusion, the telomeric DNA values by IQ FISH analyses can be used as an effective age-marker in predicting the chronological age of chickens. The study has implications in the breeding and population genetics of poultry, especially the reproductive potential.

• Asian Pacific Journal of Cancer Prevention
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• 제17권4호
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• pp.1993-1998
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• 2016

The effects of carbon-ion irradiation on cancer cell telomere function have not been comprehensively studied. In our previous report cancer cells with telomere dysfunction were more sensitive to carbon-ion irradiation, but the underlying mechanisms remained unclear. Here we found that telomerase activity was suppressed by carbon-ion irradiation via hTERT down-regulation. Inhibition of telomere activity by MST-312 further increased cancer cell radiosensitivity to carbon-ion radiation. hTERT suppression caused by either carbon-ion irradiation or MST-312 impaired mitochondrial function, as indicated by decreased membrane potential, mtDNA copy number, mitochondrial mass, total ATP levels and elevated reactive oxygen species (ROS). PGC-$1{\alpha}$ expression was repressed after carbion-ion irradiation, and hTERT inhibition by MST-312 could further exacerbate this effect. Lowering the mitochondrial ROS level by MitoTEMPO could partially counteract the induction of cellular senescence induced by carbon-ion radiation and MST-312 incubation. Taken together, the current data suggest that telomere-mitochondrion links play a role in the induction of senescence in MCF-7 cells after carbon-ion irradiation.