Restriction Fragment Analysis Research Articles

High-throughput single telomere analysis using DNA microarray and fluorescent in situ hybridization.

The human telomere system is highly dynamic. Both short and long leucocyte average telomere lengths (aTL) are associated with an increased risk of cancer and early death, illustrating the complex relationship between TL and human health and the importance of assessing TL distributions with single TL analysis. A DNA microarray and telomere fluorescent in situ hybridization (DNA-array-FISH) approach was developed to measure the base-pair (bp) lengths of single telomeres. On average 32000 telomeres were measured per DNA sample with one microarray chip assaying 96 test DNA samples. Various telomere parameters, i.e. aTL and the frequency of short/long telomeres, were computed to delineate TL distribution. The intra-assay and inter-assay coefficient of variations of aTL ranged from 1.37% to 3.98%. The correlation coefficient (r) of aTL in repeated measurements ranged from 0.91 to 1.00, demonstrating high measurement precision. aTLs measured by DNA-array-FISH predicted aTLs measured by terminal restriction fragment (TRF) analysis with r ranging 0.87-0.99. A new accurate and high-throughput method has been developed to measure the bp lengths of single telomeres. The large number of single TL data provides an opportunity for an in-depth analysis of telomere dynamics and the complex relationship between telomere and age-related diseases.

RFLP-kenzy: a new bioinformatics tool for in silico detection of key restriction enzyme in RFLP technique

BackgroundToday, several bioinformatics tools are available for analyzing restriction fragment length data. RFLP-kenzy is a new bioinformatic tool for identifying restriction key enzyme that cut at least 1 sequence and a maximum of n-1 sequence.ResultsThis bioinformatic tool helps researchers to select appropriate enzymes that yield different RFLP patterns, especially from overly identical sequences with single nucleotide mutation or other small variations. By using RFLP-kenzy, multiple DNA sequences could be analyzed simultaneously and the key enzymes list is provided. The present paper also demonstrates the ability of RFLP-kenzy to identify the key enzymes through the analysis of 16S rRNA sequences and the complete genome of various genera of microorganisms.ConclusionFrom the results, several key enzymes were provided indicating the importance of this new tool in the selection of appropriate restriction enzymes.

CLINICAL COURSE OF OBESITY-ASSOCIATED ASTHMA DEPENDING ON THE GLN27GLU POLYMORPHIC VARIANT OF THE β2-ADRENORECEPTOR GENE, TAKING INTO ACCOUNT THE AGE OF ONSET

Introduction. Studies have shown that bronchial asthma (BA) associated with obesity has a more severe course, lower control, more frequent cases of low efficacy of basic treatment, and exacerbations. Two phenotypes have been distinguished in BA-obesity comorbidity based on age of onset: early atopic and late non-atopic. It is known that genetic factors associated with β2-adrenoceptor (AR) genes are important in the development of both asthma and obesity.
 The purpose of the study aimed to analyze the association of the Gln27Glu polymorphism of the β2-adrenoceptor gene with the severity of the course of bronchial asthma with obesity, taking into account the age of its onset.
 Research material and methods. 195 asthma patients with obesity consented for the study participation were examined. The control group consisted of 95 practically healthy people. Patients were divided into two clinical groups depending on the age of onset of BA: the first group included 100 patients with an early onset, the second group - 95 patients with a late onset. The diagnosis and treatment of asthma followed the guidelines of the Global Initiative for Asthma (2016) and its updated versions. The study was approved by the Bioethics Commission of the Educational and Scientific Medical Institute of Sumy State University. Determination of the Gln27Glu polymorphism of the β2-AR gene (rs1042714) was performed using the polymerase chain reaction with the subsequent analysis of restriction fragments. Statistical analysis of the obtained results was carried out using the SPSS-17 program. Pearson's chi-squared test was used to compare genotype distributions between experimental groups. To determine the risk of BA and obesity, odds ratios and 95% confidence intervals were calculated for dominant, recessive, superdominant, and additive models of inheritance. Their relevance was assessed using the Akaike information criterion. All tests were two-sided, and values p < 0.05 were considered statistically significant.
 Research results. The frequency of Gln/Gln, Gln/Glu and Glu/Glu genotypes according to the Gln27Glu polymorphism of the β2-AR gene in patients with early-onset obesity-associated asthma was 70.0; 25.0; 5.0% with a mild course and 55.0; 36.2; 8.8% with severe (χ2 = 1.49; p = 0.473); and with a late debut - 50.0; 43.8; 6.2% with mild and 54.0%; 31.7; 14.3%, respectively, with severe (χ2 = 2.10; p = 0.350). Despite the absence of a probable difference in the distribution of genotypes depending on the severity of the course, it was found that the frequency of homozygotes for the minor allele was 1.8 times higher in patients with a severe course of early BA and 2.3 times higher in late BA compared to that in patients with mild BA course.
 The risk of early-onset BA with obesity and a severe course showed no association in all models of inheritance, and in patients with late-onset BA, there was a 1.66-fold increase (95% CI (1.03 – 2.72), p = 0.04) in the additive inheritance model (p = 0.04).
 Conclusions. There are no statistically significant differences in the distribution of genotypes according to the Gln27Glu polymorphism of the β2-AR gene depending on the severity of the course of early and late BA with obesity. The risk of developing a severe course of early BA did not depend on the Gln27Glu polymorphism of the β2-AR gene, and late BA increased by 1.66 times in the additive model of inheritance.

The association between age and telomere length is age-dependent: Evidence for a threshold model of telomere length maintenance.

Telomere length and dynamics are commonly used biomarkers of somatic state, yet the role of telomeres underlying the aging process is still debated. Indeed, to date, empirical evidence for an association between age and telomere length is mixed. Here, we test if the age-dependency of the association between age and telomere length can provide a potential explanation for the reported inconsistencies across studies. To this end, we quantified telomere length by telomere restriction fragment analysis in two groups of Japanese quail (Coturnix japonica) that differed in their age distribution. One group consisted of young adults only, whereas the second group consisted of adults across a wide range of ages. In the young adults group, there was a highly significant negative association between telomere length and age, whereas no association between age and telomere length was found in the all-ages adults group. This difference between groups was not due to telomere length-dependent selective disappearance. Our results shows that the association between telomere length and age is age-dependent and suggest that the costs and benefits associated with telomere maintenance are dynamic across an individual's life course.

Comparative Application of Terminal Restriction Fragment Analysis Tools to Large-Scale Genomic Assays.

The analysis of telomere length is an important component of many studies aiming to characterize the role of telomere maintenance mechanisms in cellular lifespan, disease, or in general chromosome protection and DNA replication pathways. Several powerful methods to accurately measure the telomere length from Southern blots have been developed, but their utility for large-scale genomic studies has not been previously evaluated. Here, we performed a comparative analysis of two recently developed programs, TeloTool and WALTER, for the extraction of mean telomere length values from Southern blots. Using both software packages, we measured the telomere length in two extensive experimental datasets for the model plant Arabidopsis thaliana, consisting of 537 natural accessions and 65 T-DNA (transfer DNA for insertion mutagenesis) mutant lines in the reference Columbia (Col-0) genotype background. We report that TeloTool substantially overestimates the telomere length in comparison to WALTER, especially for values over 4500 bp. Importantly, the TeloTool- and WALTER-calculated telomere length values correlate the most in the 2100-3500 bp range, suggesting that telomeres in this size interval can be estimated by both programs equally well. We further show that genome-wide association studies using datasets from both telomere length analysis tools can detect the most significant SNP candidates equally well. However, GWAS analysis with the WALTER dataset consistently detects fewer significant SNPs than analysis with the TeloTool dataset, regardless of the GWAS method used. These results imply that the telomere length data generated by WALTER may represent a more stringent approach to GWAS and SNP selection for the downstream molecular screening of candidate genes. Overall, our work reveals the unanticipated impact of the telomere length analysis method on the outcomes of large-scale genomic screens.

Polymorphism of proinflammatory inerleukin genes in primary open-angle glaucoma

Glaucoma is a degenerative disease of the optic nerve, accompanied by the death of retinal ganglion cells (RGCs) and loss of vision. An important role in the pathogenesis of glaucoma is ascribed to activated microglia, which produce pro-inflammatory interleukins and initiate GCS apoptosis. It has been established that single nucleotide polymorphisms of interleukin genes modify the development of neuroinflammation, but their effect on the risk of developing glaucoma is not yet fully established. Our aim was to determine the pathogenetic role of gene polymorphisms in TNFα and IL1β in the development of primary open-angle glaucoma.We have observed 56 patients of Russian nationality from the South of Russia with primary open-angle glaucoma (POAG), 28 patients with stage I, 16 with stage II, 12 with stage III POAG. The single nucleotide polymorphisms TNFα 308G>A (rs1800629) and IL1β -31 Т>С (rs1143627) were studied by restriction fragment analysis of PCR products. The level of pro-inflammatory cytokines (TNFα and IL1β) in the lacrimal fluid of patients with POAG was evaluated by enzyme-linked immunosorbent assay (Vector-Best test system). To perform optical coherence tomography by analysing the thickness of retinal nerve fiber layer (RNFL) with volume and area of the neuroretinal rim using Torson 3D OST 1000 apparatus.Results: in patients with POAG, we have found more common incidence of TNFα 308A (OR = 5.21, p = 0.001), and IL1β-31 T alleles (OR = 1.99, p = 0.04). An increased risk of developing POAG was found in carriers of genotypes 308A/A (OR = 6.30, p = 0.049), 308G/A (OR = 3.60, p = 0.049) and -31T/T (OR = 2.67, p = 0.04). The highest levels of TNFα were determined in the 308A/A group (190 (153.0-220.0) pg/mL), IL1β were in the group (-31) T/T – 6.50 (4.10-7.00) pg/mL. A decreased thickness of the retinal nerve fibers was observed in the patients with TNFα G308A genotype (59.5; 40.0 to 78.0 µm, p = 0.03), and in TNFα A308A carriers (79.0; 65.0 to 80.0 µm, p = 0.001).The TNFα 308 G/A (rs1800629), along with IL1β, -31Т/C (rs1143627) cytokine gene polymorphisms are associated with development of primary open-angle glaucoma. TNFα 308A, IL1β -31T alleles, as well as the 308G/A, 308A/A and -31T/T genotypes seem to be the risk factors for POAG in Russian population. High content of TNFα in the lacrimal fluid was found in the carriers of 308A/A genotype and -31T/T IL1β genotype. The lowest thickness of the retinal nerve fiber layer was observed in the carriers of tTNFα A308A and TNFα G308A genotypes.

Profile of Gut Bacteria in Hypertensive Patients Based on Terminal Restriction Fragment Length Polymorphism Analysis

Hypertension is a severe public health problem due to its high prevalence worldwide. About 7.5 million deaths or 12.8% of all annual deaths worldwide occur due to high blood pressure. The hypertensive disease is also associated with the intestinal bacteria. To our knowledge, the diversity of the gut bacteria in hypertensive patients has not been reported yet in Indonesia. Thus, the aims of this study were to analyze profile of gut bacteria in hypertensive patients compared to non-hypertensive based on metagenomic analysis, Terminal Restriction Fragment Length Polymorphism (T-RFLP). The results of the affiliation analysis of the entire Terminal Restriction Fragments (TRF) contained 6 groups of bacteria from 26 TRFs in hypertensive and non-hypertensive respondents. Cutting the 16S rRNA gene with the BslI restriction enzyme successfully detected intestinal bacterial groups, namely Clostridium subcluster XIVa, Prevotella, Clostridium cluster IV, Clostridium cluster XI, Bacteroides and others. In hypertensive patients, a higher relative abundance of bacterial groups showed in Clostridium cluster XI, Clostridium cluster IV and Clostridium subcluster XIVa. The abundance of Bacteroides and Prevotella groups in hypertensive patients were lower than non-hypertensive. The abundance of enterotype I and enterotype II was lower in hypertensive patients than non-hypertensive. Contrarily to that enterotype III cluster. It is worth noting that the F/B ratio was higher in hypertensive patients than that in non-hypertensive. Our data suggest that the gut bacteria profile of hypertensive patients differs to that non-hypertensive.

Дослідження зв'язку фенотипу бронхіальна астма-ожиріння з ER22/23EK і TTH111I поліморфізмами гена глюкокортикоїдного рецептора

(GR) gene with the body mass index (BMI) of patients with bronchial asthma (BA), considering the age of BA onset. Materials and methods. 553 patients with BA and 95 practically healthy persons who previously signed an informed consent to participate in the study were examined. Patients were divided into two clinical groups according to the age of BA onset. Group I included 282 patients with late-onset of asthma (late asthma phenotype), and Group II included 271 patients with early onset (early asthma phenotype). The diagnosis of BA and the severity of the course were established according to the recommendations of GINA-2016 and subsequent versions. Diagnosis of obesity was carried out in accordance with the Order of the Ministry of Health of Ukraine dated August 5, 2009, No. 574, and the European Association for the Study of Obesity (EASO, 2016). The study was approved by the Bioethics Committee of the Medical Institute of Sumy State University. Determination of ER22/23EK (rs 6189/6190) and Tth111I (rs10052957) polymorphisms of the GR gene was performed using the polymerase chain reaction followed by the analysis of restriction fragments. Statistical analysis of the obtained results was carried out using the SPSS-17 program. The results. The analysis of anthropometric parameters showed that among the examined patients with BA, there were 152 (27.5 %) patients with normal body weight (NBW), 206 (37.3 %) were overweight, and 195 (35.2 %) with obesity. Visceral type of obesity was verified among all patients. It was established that among overweight and obese BA patients, there was a higher frequency of GG genotype according to the ER22/23EK polymorphism of the GR gene compared to patients with NBW. Heterozygotes were found 5.6 and 3.5 times more often in patients with normal body weight compared to patients with obesity. Analysis of the ratio of G and A alleles depending on BMI shows a higher frequency of the G allele in obese patients compared to patients with NBW. The distribution of alleles and genotypes according to the Tth111I polymorphism in the examined patients with BA depending on the BMI shows a twice higher frequency of homozygotes for the main C allele in overweight and patients with obesity compared to patients with NBW. Carriers of homozygotes for the minor allele were detected 4.7 times and 2.1 times more often in patients with NBW compared to overweight patients and with obesity. A probable difference in the distribution of alleles and genotypes according to the Tth111I polymorphism of the GR gene was established in patients with early and late BA (p = 0.001). Carriers of homozygotes for the main allele of CC were found more often in patients with early and late BA in the presence of obesity. Conclusions. A higher frequency of the GG genotype according to the ER22/23EK polymorphism of the GR gene and homozygotes according to the main CC allele according to the Tth111I polymorphism of the GR gene in overweight BA patients and with obesity compared to patients with NBW was proven. The protective role of the ER22/23EK polymorphism of the GR gene in relation to the occurrence of obesity in the dominant, superdominant and additive models of inheritance and the Tth111I polymorphism of the GR gene in the superdominant model was established. A higher frequency of carriers of homozygotes for the main C allele in patients with early-onset and late-onset BA in the presence of obesity compared to patients with NBW, a protective role of the Tth111I polymorphism of the GR gene on the risk of developing obesity in patients with late-onset BA in superdominant and recessive models of inheritance was established. Key words: bronchial asthma, obesity, onset, course, ER22/23EK, and Tth111I polymorphisms of the glucocorticoid receptor gene.

Reliable assessment of telomere maintenance mechanisms in neuroblastoma

BackgroundTelomere maintenance mechanisms (TMM) are a hallmark of high-risk neuroblastoma, and are conferred by activation of telomerase or alternative lengthening of telomeres (ALT). However, detection of TMM is not yet part of the clinical routine, and consensus on TMM detection, especially on ALT assessment, remains to be achieved.MethodsWhole genome sequencing (WGS) data of 68 primary neuroblastoma samples were analyzed. Telomere length was calculated from WGS data or by telomere restriction fragment analysis (n = 39). ALT was assessed by C-circle assay (CCA, n = 67) and detection of ALT-associated PML nuclear bodies (APB) by combined fluorescence in situ hybridization and immunofluorescence staining (n = 68). RNA sequencing was performed (n = 64) to determine expression of TERT and telomeric long non-coding RNA (TERRA). Telomerase activity was examined by telomerase repeat amplification protocol (TRAP, n = 15).ResultsTumors were considered as telomerase-positive if they harbored a TERT rearrangement, MYCN amplification or high TERT expression (45.6%, 31/68), and ALT-positive if they were positive for APB and CCA (19.1%, 13/68). If all these markers were absent, tumors were considered TMM-negative (25.0%, 17/68). According to these criteria, the majority of samples were classified unambiguously (89.7%, 61/68). Assessment of additional ALT-associated parameters clarified the TMM status of the remaining seven cases with high likelihood: ALT-positive tumors had higher TERRA expression, longer telomeres, more telomere insertions, a characteristic pattern of telomere variant repeats, and were associated with ATRX mutations.ConclusionsWe here propose a workflow to reliably detect TMM in neuroblastoma. We show that unambiguous classification is feasible following a stepwise approach that determines both, activation of telomerase and ALT. The workflow proposed in this study can be used in clinical routine and provides a framework to systematically and reliably determine telomere maintenance mechanisms for risk stratification and treatment allocation of neuroblastoma patients.

Spinal muscular atrophy carrier frequency in Saudi Arabia.

Spinal Muscular Dystrophy (SMA) is one of the leading causes of death in infants and young children from heritable diseases. Although no large-scale popultion-based studies have been done in Saudi Arabia, it is reported that the incidence of SMA is higher in the Saudi population partly because of the high degree of consanguineous marriages. The final analysis included 4198 normal volunteers aged between 18 and 25 years old, 54.7% males, and 45.3% females. Whole blood was spotted directly from finger pricks onto IsoCode StixTM and genomic DNA was isolated using one triangle from the machine. To discern the SMN1 copy number independently from SMN2, Multiplex PCR with Dral restriction fragment analysis was completed. We used the carrier frequency and population-level data to estimate the prevalence of SMA in the population using the life-table method. This data analysis showed the presence of one copy of the SMN1 gene in 108 samples and two copies in 4090 samples, which resulted from a carrier frequency of 2.6%. The carrier frequency was twofold in females reaching 3.7% compared to 1.6% in males. 27% of participants were children of first-cousin marriages. We estimated the birth incidence of SMA to be 32 per 100,000 birth and the total number of people living with SMA in the Kingdom of Saudi Arabia to be 2265 of which 188 are type I, 1213 are type II, and 8,64 are type III. The SMA carrier rate of 2.6% in Saudi control subjects is slightly higher than the reported global frequency of 1.25 to 2% with links to the high degree of consanguinity.

BALKAN ENDEMIC NEPHROPATHY, PULSE WAVE VELOCITY AND INCREASED TELOMERE LENGTH-ASSOCIATED CARDIOVASCULAR MORTALITY IN PATIENTS UNDERGOING CHRONIC HEMODIALYSIS

Objective: Balkan endemic nephropathy (BEN) is characterized with later onset, milder forms of hypertension and lower pulse wave velocity (PWV)). We hypothesized that telomere length (TL) would be longer in BEN patients and associated with lower PWV and less cardiovascular (CV) mortality. Design and method: On total 124 hemodialysed (HD) patients (68 BEN, 56 non-BEN; 48.4% men; 65 ± 14 years) were enrolled and followed-up for 25 months. Blood pressure and PWV were determined before mid-week dialysis. TL was determined by telomere restriction fragment analysis. Results: Age-sex adjusted TL was significantly longer in the BEN group (7.19 vs 6.79; p < 0.001) despite being significantly older. In the BEN group TL was associated with PWV (beta = -0.373, p < 0.05), and in the non-BEN group with age (beta = -0.680, p < 0.01). In the full-adjusted model of multivariate linear regression analyses significant predictors of TL were systolic BP/PWV, and age in the BEN and the non-BEN group, respectively. BEN patients died significantly less frequently from CV events than non-BEN patients (p < 0.001) and lived significantly longer (log-rank p = 0.04). Patients who died had significantly shorter TL than survivors (p < 0.001). In the Cox Regression analysis older age, diagnosis of non-BEN and shorter TL were determinants of shorter survival in the entire cohort. In the BEN group shorter TL was the only determinant of shorter survival (HR 0.11 [95% CI 0.03, 0.35]). To analyze the diagnostic value of TL for CV mortality we used ROC analysis that revealed TL < 6.21 Kb to be useful for prediction of CV mortality in patients undergoing chronic HD. Conclusions: Shorter TL is associated with CV mortality in patients undergoing chronic HD. BEN patients had longer TL and longer survival than other ESKD patients. PWV was significant predictor of TL in BEN patients. This study confirmed our hypothesis that BEN is associated with slower vascular aging.

Association between mitochondrial DNA haplogroups J and K, serum branched-chain amino acids and lowered capability for endurance exercise

BackgroundEndurance exercise training promotes the catabolism of branched-chain amino acids (BCAAs) in skeletal muscles. We have previously shown that mitochondrial DNA (mtDNA) haplogroups J and K are markers of low responders in endurance training. In this paper, we hypothesize that BCAA catabolism is a surrogate marker of lower respiratory chain activity attributed to these haplogroups. We evaluated whether exercise-induced changes in amino acid concentrations differ between subjects harbouring mtDNA haplogroups J or K and those with non-JK haplogroups.MethodsFinnish male conscripts (N = 633) undertook the 12-min Cooper running test at the beginning and end of their military service. The intervention during the service mainly included endurance aerobic exercise and sports-related muscle training. Concentrations of seven amino acids were analysed in the serum using a high-throughput 1H NMR metabolomics platform. Total DNA was extracted from whole blood, and restriction fragment analysis was used to determine mtDNA haplogroups J and K.ResultsThe concentrations of the seven amino acids were higher following the intervention, with the exception of phenylalanine; interestingly, the increase in the concentrations of three BCAAs was larger in subjects with haplogroup J or K than in subjects with non-JK haplogroups (p = 0.029). MtDNA haplogroups J and K share two common nonsynonymous variants. Structural analysis based on crystallographic data on bovine complexes I and III revealed that the Leu18 variant in cytochrome b encoded by m.14798T > C may interfere with ubiquinone binding at the Qi site in complex III.ConclusionsThe increase in the concentrations of serum BCAAs following exercise intervention differs between subjects harbouring mtDNA haplogroup J or K and those harbouring non-JK haplogroups. Lower response in endurance training and difference in exercise-induced increase in the concentrations of serum BCAAs suggest decreased respiratory chain activity. Haplogroups J and K share m.14798T > C in MT-CYB, which may hamper the function of complex III.

Correlation between reduced telomere length and behavioural and emotional problems in left-behind children in a rural area in China

Evidence shows that being left behind experience (LBE) during childhood may increase the risks of poor psychopathological outcomes. However, it is unclear to what extent the mental health is affected by the LBE. Telomere length (TL), one of the most extensively studied biological markers of cellular ageing, provides a valuable tool for exploring the potential effects of parent-child separation on psychological problems by integrating genetic and environmental factors. In this study, a total of 613 children (mean age = 10.77, SD = 1.92) were recruited from the rural area of Deyang, Sichuan Province, China. We used a self-designed questionnaire to assess LBE, and collected psychopathological outcomes by using the Piers-Harris Children's Self-concept Scale, the Teacher's Report Form 6/18 and the Youth Self-Report 11/18. Terminal restriction fragment analysis was used to measure TL in peripheral blood leukocytes. Analyses revealed that 342 out of 613 participants (55.79%) were Left-behind children. LBE was observed to associated with shorter TL, lower self-esteem, and increased behavioural and emotional problems. The cumulative effects of LBE may be reflected by greater altered telomere homeostasis, decreased self-esteem, and worsened behavioural and emotional problems. The association of the total time of being left behind with self-esteem and behavioural and emotional problems was significantly mediated by altered telomere homeostasis, with estimated effects of 14.19%, 47.95% and 45.13%, respectively. The LBE in childhood, especially prolonged parent-child separation, increases the risk of mental health problems in childhood and adolescence.

Альдостеронсинтаза, поліморфізм її гена CYP11B2 при артеріальній гіпертензії і асоційованих з нею кардіоваскулярних захворюваннях (огляд літератури)

В огляді надані дані зарубіжної та вітчизняної літератури щодо патогенетичної ролі альдостерону, рівнів альдостеронсинтази і поліморфізмів гена даного ферменту у хворих на різні форми артеріальної гіпертензії, при асоційованих з нею захворюваннях серця і судин, фібриляції передсердь, метаболічному синдромі, патології нирок, головного мозку. Розглядаються функції альдостерону, рівнів альдостеронсинтази і поліморфізмів гена даного ферменту в серцево-судинному ремоделюванні, можливості застосування даних маркерів для диференційно-діагностичних цілей, перспективи терапевтичного використання інгібіторів альдостеронсинтази серед різних категорій хворих з ознаками артеріальної гіпертензії.

High heritability of telomere length and low heritability of telomere shortening in wild birds.

Telomere length and telomere shortening predict survival in many organisms. This raises the question of the contribution of genetic and environmental effects to variation in these traits, which is still poorly known, particularly for telomere shortening. We used experimental (cross-fostering) and statistical (quantitative genetic "animal models") means to disentangle and estimate genetic and environmental contributions to telomere length variation in pedigreed free-living jackdaws (Corvus monedula). Telomere length was measured twice in nestlings, at ages 4 (n=715) and 29days (n=474), using telomere restriction fragment (TRF) analysis, adapted to exclude interstitial telomeric sequences. Telomere length shortened significantly over the nestling period (10.4±0.3bpday-1 ) and was highly phenotypically (rP =0.95±0.01) and genetically (rG >0.99±0.01) correlated within individuals. Additive genetic effects explained a major part of telomere length variation among individuals, with its heritability estimated at h2 =0.74 on average. We note that TRF-based studies reported higher heritabilities than qPCR-based studies, and we discuss possible explanations. Parent-offspring regressions yielded similar heritability estimates for mothers and fathers when accounting for changes in paternal telomere length over life. Year effects explained a small but significant part of telomere length variation. Heritable variation for telomere shortening was low (h2 =0.09±0.11). The difference in heritability between telomere length (high) and telomere shortening (low) agrees with evolutionary theory, in that telomere shortening has stronger fitness consequences in this population. Despite the high heritability of telomere length, its evolvability, which scales the additive genetic variance by mean telomere length, was on average 0.48%. Hence, evolutionary change of telomere length due to selection is likely to be slow.

Exposure to food insecurity increases energy storage and reduces somatic maintenance in European starlings (Sturnus vulgaris).

Birds exposed to food insecurity—defined as temporally variable access to food—respond adaptively by storing more energy. To do this, they may reduce energy allocation to other functions such as somatic maintenance and repair. To investigate this trade-off, we exposed juvenile European starlings (Sturnus vulgaris, n = 69) to 19 weeks of either uninterrupted food availability or a regime where food was unpredictably unavailable for a 5-h period on 5 days each week. Our measures of energy storage were mass and fat scores. Our measures of somatic maintenance were the growth rate of a plucked feather, and erythrocyte telomere length (TL), measured by analysis of the terminal restriction fragment. The insecure birds were heavier than the controls, by an amount that varied over time. They also had higher fat scores. We found no evidence that they consumed more food overall, though our food consumption data were incomplete. Plucked feathers regrew more slowly in the insecure birds. TL was reduced in the insecure birds, specifically, in the longer percentiles of the within-individual TL distribution. We conclude that increased energy storage in response to food insecurity is achieved at the expense of investment in somatic maintenance and repair.

Increased telomere length in patients with frontotemporal dementia syndrome

BackgroundTelomeres are repetitive DNA sequences of TTAGGG at the ends of chromosomes. Many studies have shown that telomere shortening is associated with aging-related diseases, such as cardiovascular diseases, hypertension, diabetes, cancer, and various neurodegenerative diseases, including Alzheimer's disease, vascular dementia, Parkinson's disease, and dementia with Lewy bodies. However, changes in telomere length (TL) in patients with frontotemporal dementia (FTD) syndrome are unclear. Accordingly, in this study, we assessed TL in blood samples from patients with FTD syndrome. MethodsAbsolute TL was measured in peripheral blood leukocytes from 53 patients with FTD syndromes (25 with behavioral variant FTD, 19 with semantic variant primary progressive aphasia [PPA], six with nonfluent/agrammatic variant PPA, and three with amyotrophic lateral sclerosis [ALS] plus) and 28 cognitively unimpaired (CU) controls using terminal restriction fragment analysis. ResultsTL was significantly longer in the FTD group than in the CU group. All FTD subtypes had significantly longer TL than controls. There were no significant differences in TL among FTD syndromes. No significant correlations were found between TL and demographic factors in the FTD group. ConclusionsLonger telomeres were associated with FTD syndrome, consistent with a recent report demonstrating that longer telomeres are related to ALS. Therefore, our results may support a shared biology between FTD and ALS. More studies with larger sample sizes are needed.

Continuous reference intervals for leukocyte telomere length in children: the method matters.

Children with very short telomeres commonly develop bone marrow failure and other severe diseases. Identifying the individuals with short telomeres can improve outcome of bone marrow transplantation, with accurate diagnosis requiring the use of age-matched reference intervals (RIs). This study aimed to establish RIs for telomere length (TL) in children using three commonly used methods for TL measurement. Healthy children aged 30days to 18 years were recruited for assessment using age as a continuous variable. Venous blood samples were collected and leukocyteTL was measured using terminal restriction fragment (TRF) analysis, quantitative PCR (QPCR) and flow cytometry with fluorescence in situ hybridization (Flow-FISH). Fractional polynomial model and quantile regression were performedto generate continuous RIs. Factors that might contribute to variation in TL, such as gender, were also examined. A total of 212 samples were analyzed. Continuous RIs are presented as functions of age. TRF analysis and QPCR showed significant negative correlation between TL and age (r=-0.28 and r=-0.38, p<0.001). In contrast, Flow-FISH showed no change in TL with age (r=-0.08, p=0.23). Gender did not have significant influence on TL in children. This study provides three options to assess TL in children by establishing method-specific continuous RIs. Choosing which method to use will depend on several factors such as amount and type of sample available and required sensitivity to age-related change.

Telomere Length in Valve Tissue Is Shorter in Individuals With Aortic Stenosis and in Calcified Valve Areas

BackgroundShort telomere length (TL) is associated with age-related diseases, in particular cardiovascular diseases. However, whether the onset and course of aortic stenosis (AS) is linked to TL in aortic valves remains unknown.ObjectivesTo assess telomere dynamics (TL and telomerase activity) in aortic valves and the possible implication of TL in onset and course of AS.MethodsDNA was extracted from aortic valves obtained from 55 patients (78.2% men; age, 37–79 years), who had undergone replacement surgery due to AS (AS group, n = 32), aortic valve regurgitation and aortic dilation (Non-AS group, n = 23). TL was measured by telomere restriction fragment analysis (TRF) in calcified and non-calcified aortic valve areas. Telomerase activity was evaluated using telomerase repeat amplification protocol (TRAP) in protein extracts from non-calcified and calcified areas of valves obtained from 4 additional patients (50% men; age, 27–70 years).ResultsTL was shorter in calcified aortic valve areas in comparison to non-calcified areas (n = 31, 8.58 ± 0.73 kb vs. 8.12 ± 0.75 kb, p < 0.0001), whereas telomerase activity was not detected in any of those areas. Moreover, patients from AS group displayed shorter telomeres in non-calcified areas than those from the Non-AS group (8.40 ± 0.64 kb vs. 8.85 ± 0.65, p = 0.01).ConclusionsShort telomeres in aortic valves may participate in the development of AS, while concurrently the calcification process seems to promote further local decrease of TL in calcified areas of valves.

14 Telomere length in cloned camels produced by somatic cell nuclear transfer is not different from that in their naturally produced counterparts

There are controversial reports on the restoration of eroded telomere length in offspring produced by somatic cell nuclear transfer (SCNT) in different animal species. To the best of our knowledge, no earlier studies report telomere length in naturally produced or cloned animals in any of the camelid species. Therefore, the present study was conducted to estimate the telomere length in dromedary camels produced by SCNT, and their age-matched naturally produced counterparts by terminal restriction fragment (TRF) analysis. Genomic DNA was extracted from venous blood collected from 6 cloned animals (aged 3, 12, and 24 months), and their age-matched counterparts by a conventional phenol/chloroform protocol. Denatured and neutralized DNA was blotted onto a positively charged nylon membrane and fixed by baking at 80°C for 3h. After washing in a prewarmed digoxigenin (DIG) easy hybridization solution at 42°C for 1h, DNA hybridization was carried out using a telomere (TTAGGG)n-specific, DIG-labelled hybridization probe (Roche Diagnostics, Germany) at 42°C for 4h. Stringent washes were carried out at the same temperature, followed by chemiluminescence reaction. The signals were captured using the Azure Biosystems C600 gel documentation system. Molecular weights of the unknown TRF bands on the gel were calculated using known molecular weight marker provided by Telo TAGGG Telomere Length Assay Kit (Roche Diagnostics). A TeloTool program from MATLAB software with a built-in probe intensity correction algorithm was used for TRF analysis. The experiment was replicated 3 times, and the data, presented as mean±s.e.m., were analysed using a 2-sample t-test (Minitab statistical software). No difference (P&amp;gt;0.05) was found in the mean telomere length of cloned camels compared with their naturally produced age-matched counterparts (21.7±0.3 vs. 22.1±0.3; 21.9±0.3 vs. 22.1±0.3; 22.2±0.5 vs. 22.0±0.1; 20.5±0.5 vs. 22.5±0.7; 20.1±0.1 vs. 22.5±0.7; 21.7±1.1 vs. 22.6±0.2), respectively. In conclusion, this is the first study where telomere length has been reported in naturally produced and cloned dromedary camels produced by SCNT. We found that telomere lengths in cloned camels were similar to those of their age-matched naturally produced counterparts, suggesting that the camel cytoplast reprograms the somatic cell nucleus and restores the telomere length to its totipotency stage.