WorldWideScience

Sample records for human dna quantitation

  1. Linkage of DNA Methylation Quantitative Trait Loci to Human Cancer Risk

    Directory of Open Access Journals (Sweden)

    Holger Heyn

    2014-04-01

    Full Text Available Epigenetic regulation and, in particular, DNA methylation have been linked to the underlying genetic sequence. DNA methylation quantitative trait loci (meQTL have been identified through significant associations between the genetic and epigenetic codes in physiological and pathological contexts. We propose that interrogating the interplay between polymorphic alleles and DNA methylation is a powerful method for improving our interpretation of risk alleles identified in genome-wide association studies that otherwise lack mechanistic explanation. We integrated patient cancer risk genotype data and genome-scale DNA methylation profiles of 3,649 primary human tumors, representing 13 solid cancer types. We provide a comprehensive meQTL catalog containing DNA methylation associations for 21% of interrogated cancer risk polymorphisms. Differentially methylated loci harbor previously reported and as-yet-unidentified cancer genes. We suggest that such regulation at the DNA level can provide a considerable amount of new information about the biology of cancer-risk alleles.

  2. Quantitation of Human Papillomavirus DNA in Plasma of Oropharyngeal Carcinoma Patients

    Energy Technology Data Exchange (ETDEWEB)

    Cao Hongbin; Banh, Alice [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Kwok, Shirley [Department of Pathology, Stanford University School of Medicine, Stanford, CA (United States); Shi Xiaoli; Wu, Simon; Krakow, Trevor; Khong, Brian; Bavan, Brindha [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Bala, Rajeev; Pinsky, Benjamin A. [Department of Pathology, Stanford University School of Medicine, Stanford, CA (United States); Colevas, Dimitrios [Department of Medicine, Stanford University School of Medicine, Stanford, CA (United States); Pourmand, Nader [Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, CA (United States); Koong, Albert C. [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States); Kong, Christina S. [Department of Pathology, Stanford University School of Medicine, Stanford, CA (United States); Le, Quynh-Thu, E-mail: qle@stanford.edu [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA (United States)

    2012-03-01

    Purpose: To determine whether human papillomavirus (HPV) DNA can be detected in the plasma of patients with HPV-positive oropharyngeal carcinoma (OPC) and to monitor its temporal change during radiotherapy. Methods and Materials: We used polymerase chain reaction to detect HPV DNA in the culture media of HPV-positive SCC90 and VU147T cells and the plasma of SCC90 and HeLa tumor-bearing mice, non-tumor-bearing controls, and those with HPV-negative tumors. We used real-time quantitative polymerase chain reaction to quantify the plasma HPV DNA in 40 HPV-positive OPC, 24 HPV-negative head-and-neck cancer patients and 10 non-cancer volunteers. The tumor HPV status was confirmed by p16{sup INK4a} staining and HPV16/18 polymerase chain reaction or HPV in situ hybridization. A total of 14 patients had serial plasma samples for HPV DNA quantification during radiotherapy. Results: HPV DNA was detectable in the plasma samples of SCC90- and HeLa-bearing mice but not in the controls. It was detected in 65% of the pretreatment plasma samples from HPV-positive OPC patients using E6/7 quantitative polymerase chain reaction. None of the HPV-negative head-and-neck cancer patients or non-cancer controls had detectable HPV DNA. The pretreatment plasma HPV DNA copy number correlated significantly with the nodal metabolic tumor volume (assessed using {sup 18}F-deoxyglucose positron emission tomography). The serial measurements in 14 patients showed a rapid decline in HPV DNA that had become undetectable at radiotherapy completion. In 3 patients, the HPV DNA level had increased to a discernable level at metastasis. Conclusions: Xenograft studies indicated that plasma HPV DNA is released from HPV-positive tumors. Circulating HPV DNA was detectable in most HPV-positive OPC patients. Thus, plasma HPV DNA might be a valuable tool for identifying relapse.

  3. Quantitative screening of single copies of human papilloma viral DNA without amplification.

    Science.gov (United States)

    Li, Jiangwei; Lee, Ji-Young; Yeung, Edward S

    2006-09-15

    We describe a novel quantitative viral screening method based on single-molecule detection that does not require amplification. DNA of human papilloma virus (HPV), the major etiological agent of cervical cancer, served as the screening target in this study. Eight 100-nucleotide single-stranded DNA probes were designed complementary to the E6-E7 gene of HPV-16 DNA. The probes were covalently stained with Alexa Fluor 532 and hybridized to the target in solution. The individual hybridized molecules were imaged with an intensified charge-coupled device (ICCD) in two ways. In the single-color mode, target molecules were detected via fluorescence from hybridized probes only. This system could detect HPV-16 DNA in the presence of human genomic DNA down to 0.7 copy/cell and had a linear dynamic range of over 6 orders of magnitude. In the dual-color mode, we employed fluorescence resonance energy transfer and added YOYO-3 dye as the acceptor. The two colors from Alexa Fluor 532 and YOYO-3 were dispersed by a transmission grating located in front of the ICCD. With this reinforced criterion for identifying the hybridized molecules, zero false-positive count was achieved. We also showed that DNA extracts from Pap test specimens did not interfere with the measurements.

  4. Quantitative real-time PCR (qPCR) assay for human-dog-cat species identification and nuclear DNA quantification.

    Science.gov (United States)

    Kanthaswamy, S; Premasuthan, A; Ng, J; Satkoski, J; Goyal, V

    2012-03-01

    In the United States, human forensic evidence collected from crime scenes is usually comingled with biomaterial of canine and feline origins. Knowledge of the concentration of nuclear DNA extracted from a crime scene biological sample and the species from which the sample originated is essential for DNA profiling. The ability to accurately detect and quantify target DNA in mixed-species samples is crucial when target DNA may be overwhelmed by non-target DNA. We have designed and evaluated a species-specific (human, dog and cat) nuclear DNA identification assay based on the TaqMan(®) quantitative real-time PCR (qPCR) technology that can simultaneously detect and measure minute quantities of DNA specific to either humans, dogs and/or cats. The fluorogenic triplex assay employs primers and hydrolysis probes that target the human TH01 locus as well as the dog and cat Melanocortin 1 Receptor (MC1R) sequences in a species-specific manner. We also demonstrate that the assay is a highly sensitive, reliable and robust method for identifying and quantifying mixed-species templates of human-dog-cat origin with as little as 0.4 pg of human and cat nuclear DNA, respectively, and 4.0 pg of dog nuclear DNA. Published by Elsevier Ireland Ltd.

  5. Quantitive DNA Fiber Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Chun-Mei; Wang, Mei; Greulich-Bode, Karin M.; Weier, Jingly F.; Weier, Heinz-Ulli G.

    2008-01-28

    Several hybridization-based methods used to delineate single copy or repeated DNA sequences in larger genomic intervals take advantage of the increased resolution and sensitivity of free chromatin, i.e., chromatin released from interphase cell nuclei. Quantitative DNA fiber mapping (QDFM) differs from the majority of these methods in that it applies FISH to purified, clonal DNA molecules which have been bound with at least one end to a solid substrate. The DNA molecules are then stretched by the action of a receding meniscus at the water-air interface resulting in DNA molecules stretched homogeneously to about 2.3 kb/{micro}m. When non-isotopically, multicolor-labeled probes are hybridized to these stretched DNA fibers, their respective binding sites are visualized in the fluorescence microscope, their relative distance can be measured and converted into kilobase pairs (kb). The QDFM technique has found useful applications ranging from the detection and delineation of deletions or overlap between linked clones to the construction of high-resolution physical maps to studies of stalled DNA replication and transcription.

  6. Universal real-time PCR assay for quantitation and size evaluation of residual cell DNA in human viral vaccines.

    Science.gov (United States)

    André, Murielle; Reghin, Sylviane; Boussard, Estelle; Lempereur, Laurent; Maisonneuve, Stéphane

    2016-05-01

    Residual host cellular DNA (rcDNA) is one of the principal risk associated with continuous cell lines derived medicines such as viral vaccines. To assess rcDNA degradation, we suggest two quantitative real-time PCR assays designed to separately quantify target sequences shorter and longer than the 200 bp risk limit, the relative abundance of both targets reflecting the extent of rcDNA fragmentation. The conserved multicopy ribosomal 18S RNA gene was targeted to detect host cell templates from most mammalian cell substrates commonly used in the manufacture of human viral vaccines. The detection range of the method was assessed on purified DNA templates from different animal origins. The standard calibrator origin and structural conformation were shown crucial to achieve accurate quantification. Artificial mixtures of PCR products shorter and longer than 200 bp were used as a model to check the ability of the assay to estimate the fragment size distribution. The method was successfully applied to a panel of Vero cell derived vaccines and could be used as a universal method for determination of both content and size distribution of rcDNA in vaccines. Copyright © 2016 International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

  7. Quantitative analysis of DNA methylation at all human imprinted regions reveals preservation of epigenetic stability in adult somatic tissue

    Directory of Open Access Journals (Sweden)

    Woodfine Kathryn

    2011-01-01

    Full Text Available Abstract Background Genes subject to genomic imprinting are mono-allelically expressed in a parent-of-origin dependent manner. Each imprinted locus has at least one differentially methylated region (DMR which has allele specific DNA methylation and contributes to imprinted gene expression. Once DMRs are established, they are potentially able to withstand normal genome reprogramming events that occur during cell differentiation and germ-line DMRs are stably maintained throughout development. These DMRs, in addition to being either maternally or paternally methylated, have differences in whether methylation was acquired in the germ-line or post fertilization and are present in a variety of genomic locations with different Cytosine-phosphate guanine (CpG densities and CTCF binding capacities. We therefore examined the stability of maintenance of DNA methylation imprints and determined the normal baseline DNA methylation levels in several adult tissues for all imprinted genes. In order to do this, we first developed and validated 50 highly specific, quantitative DNA methylation pyrosequencing assays for the known DMRs associated with human imprinted genes. Results Remarkable stability of the DNA methylation imprint was observed in all germ-line DMRs and paternally methylated somatic DMRs (which maintained average methylation levels of between 35% - 65% in all somatic tissues, independent of gene expression. Maternally methylated somatic DMRs were found to have more variation with tissue specific methylation patterns. Most DMRs, however, showed some intra-individual variability for DNA methylation levels in peripheral blood, suggesting that more than one DMR needs to be examined in order to get an overall impression of the epigenetic stability in a tissue. The plasticity of DNA methylation at imprinted genes was examined in a panel of normal and cancer cell lines. All cell lines showed changes in DNA methylation, especially at the paternal germ

  8. Development of a quantitation approach for total human and male DNA based on real time PCR followed by high resolution melting analysis.

    Science.gov (United States)

    Ginart, Santiago; Caputo, Mariela; Alechine, Evguenia; Corach, Daniel; Sala, Andrea

    2016-10-01

    We developed and validated a total human DNA quantitation technique that simultaneously allows male DNA detection. This assay, called Amel-Y, is a duplex Real Time PCR followed by HRM (high resolution melting) analysis using the intercalating dye SYTO9. Amel-Y duplex produces two amplicons, one for the amelogenin gene (106/112 bp, female/male) and another (84 bp) corresponding to human Y chromosome-specific fragment to detect male DNA. After HRM analysis, two melting peaks differing in 5.3°C-5.5°C are detected if both male and female DNA are present and only one if only female DNA is present. For specificity assessment, the inclusion of high concentrations of bacterial and fungal DNA in the quantitation reactions allowed discarding species cross-reactivity. A set of crime scene evidence from forensic casework has been quantified with commercial kits and compared with Amel-Y duplex. Our method detected male DNA from a concentration of 18 pg/μL and supports autosomal/Y DNA detection ratio up to 200:1. A limitation of the technique is its inability to quantify male and female donnors in a mixed sample. The Amel-Y duplex demonstrated to be an efficient system for quantifying total human DNA being a specific, rapid, sensitive, and cost-effective method suitable for mixed DNA samples and applicable to any field where human DNA quantification is required, such as molecular diagnosis, population genetics, and forensic identification. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Development and validation of InnoQuant® HY, a system for quantitation and quality assessment of total human and male DNA using high copy targets.

    Science.gov (United States)

    Loftus, Andrew; Murphy, Gina; Brown, Hiromi; Montgomery, Anne; Tabak, Jonathan; Baus, James; Carroll, Marion; Green, André; Sikka, Suresh; Sinha, Sudhir

    2017-07-01

    The development and validation of InnoQuant® HY, a real-time PCR system containing four DNA targets-two RE autosomal targets of different sizes, male specific targets, and an internal positive control target-are described herein. The ratio of the two autosomal targets provides a Degradation Index, or a quantitative value of a sample's degradation state. The male specific targets are multi-copy targets located on the Y chromosome, which provides information about a sample's male DNA composition. The experimental results demonstrate InnoQuant HY as a robust qPCR method producing accurate DNA quantitation results even at low dynamic ranges, with reproducibility among population groups. The system is human specific with low level higher primate cross reactivity and is able to consistently and reproducibly detect sub-picogram concentrations of human and human male DNA. The use of high copy number Alu and SVA (>1000 copies per genome) retrotransposable elements as the two autosomal targets significantly enhances both sensitivity and reproducibility of determination of DNA quantitation as well as DNA degradation in forensic samples. The inclusion of a sensitive multi-copy Y-chromosome specific target provides accurate quantitation of DNA from a male in challenging male-female mixtures (i.e. sexual assault samples). Even in the presence of a large excess of DNA from a female, accurate quantitation was achieved with a male to female ratio of 1:128,000. Population database studies reveal an average Short/Y target ratio of the quantification values across all four populations tested was 1.124±0.282, exhibiting the system's reproducibility across multiple populations. The results from InnoQuant HY provide a tool equipping a forensic analyst with crucial data about a sample's DNA quantitation, male:female ratio, degradation state, and the presence or absence of PCR inhibitors. With the information gained from the InnoQuant HY kit, a more streamlined and efficient workflow can

  10. [QUANTITATIVE DNA EVALUATION OF THE HIGH CARCINOGENIC RISK OF HUMAN PAPILLOMA VIRUSES AND HUMAN HERPES VIRUSES IN MALES WITH FERTILITY DISORDERS].

    Science.gov (United States)

    Evdokimov, V V; Naumenko, V A; Tulenev, Yu A; Kurilo, L F; Kovalyk, V P; Sorokina, T M; Lebedeva, A L; Gomberg, M A; Kushch, A A

    2016-01-01

    Infertility is an actual medical and social problem. In 50% of couples it is associated with the male factor and in more than 50% of cases the etiology of the infertility remains insufficiently understood. The goal of this work was to study the prevalence and to perform quantitative analysis of the human herpes viruses (HHV) and high carcinogenic risk papilloma viruses (HR HPV) in males with infertility, as well as to assess the impact of these infections on sperm parameters. Ejaculate samples obtained from 196 males fall into 3 groups. Group 1 included men with the infertility of unknown etiology (n = 112); group 2, patients who had female partners with the history of spontaneous abortion (n = 63); group 3 (control), healthy men (n = 21). HHV and HR HPV DNA in the ejaculates were detected in a total of 42/196 (21.4%) males: in 31 and 11 patients in groups 1 and 2, respectively (p > 0.05) and in none of healthy males. HHV were detected in 24/42; HR HPV, in 18/42 males (p > 0.05) without significant difference between the groups. Among HR HPV genotypes of the clade A9 in ejaculate were more frequent (14/18, p = 0.04). Comparative analysis of the sperm parameters showed that in the ejaculates of the infected patients sperm motility as well as the number of morphologically normal cells were significantly reduced compared with the healthy men. The quantification of the viral DNA revealed that in 31% of the male ejaculates the viral load was high: > 3 Ig10/100000 cells. Conclusion. The detection of HHV and HR HPV in the ejaculate is associated with male infertility. Quantification of the viral DNA in the ejaculate is a useful indicator for monitoring viral infections in infertility and for decision to start therapy.

  11. Comparative Diagnosis of Human Bocavirus 1 Respiratory Infection With Messenger RNA Reverse-Transcription Polymerase Chain Reaction (PCR), DNA Quantitative PCR, and Serology.

    Science.gov (United States)

    Xu, Man; Arku, Benedict; Jartti, Tuomas; Koskinen, Janne; Peltola, Ville; Hedman, Klaus; Söderlund-Venermo, Maria

    2017-05-15

    Human bocavirus (HBoV) 1 can cause life-threatening respiratory tract infection in children. Diagnosing acute HBoV1 infection is challenging owing to long-term airway persistence. We assessed whether messenger RNA (mRNA) detection would correlate better than DNA detection with acute HBoV1 infection. Paired serum samples from 121 children with acute wheezing were analyzed by means of serology. Quantitative polymerase chain reaction (PCR) and reverse-transcription (RT) PCR were applied to nasopharyngeal swab (NPS) samples from all acutely HBoV1-infected children and from controls with nonacute infection. By serology, 16 of 121 children (13.2%) had acute HBoV1 infection, all of whom had HBoV1 DNA in NPS samples, and 12 of 16 (75%) had HBoV1 mRNA. Among 25 children with nondiagnostic results, 6 had HBoV1 DNA in NPS samples, and 1 had mRNA. All 13 mRNA-positive samples exhibited high DNA loads (≥106 copies/mL). No mRNA persisted for 2 weeks, whereas HBoV1 DNA persisted for 2 months in 4 children; 1 year later all 15 samples were DNA negative. Compared with serology, DNA PCR had high clinical sensitivity (100%) but, because of viral persistence, low specificity (76%). In contrast, mRNA RT-PCR had low clinical sensitivity (75%) but high specificity (96%). A combination of HBoV1 serology and nasopharyngeal DNA quantitative PCR and mRNA RT-PCR should be used for accurate diagnosis of HBoV1 infection.

  12. Development and validation of InnoQuant™, a sensitive human DNA quantitation and degradation assessment method for forensic samples using high copy number mobile elements Alu and SVA.

    Science.gov (United States)

    Pineda, Gina M; Montgomery, Anne H; Thompson, Robyn; Indest, Brooke; Carroll, Marion; Sinha, Sudhir K

    2014-11-01

    There is a constant need in forensic casework laboratories for an improved way to increase the first-pass success rate of forensic samples. The recent advances in mini STR analysis, SNP, and Alu marker systems have now made it possible to analyze highly compromised samples, yet few tools are available that can simultaneously provide an assessment of quantity, inhibition, and degradation in a sample prior to genotyping. Currently there are several different approaches used for fluorescence-based quantification assays which provide a measure of quantity and inhibition. However, a system which can also assess the extent of degradation in a forensic sample will be a useful tool for DNA analysts. Possessing this information prior to genotyping will allow an analyst to more informatively make downstream decisions for the successful typing of a forensic sample without unnecessarily consuming DNA extract. Real-time PCR provides a reliable method for determining the amount and quality of amplifiable DNA in a biological sample. Alu are Short Interspersed Elements (SINE), approximately 300bp insertions which are distributed throughout the human genome in large copy number. The use of an internal primer to amplify a segment of an Alu element allows for human specificity as well as high sensitivity when compared to a single copy target. The advantage of an Alu system is the presence of a large number (>1000) of fixed insertions in every human genome, which minimizes the individual specific variation possible when using a multi-copy target quantification system. This study utilizes two independent retrotransposon genomic targets to obtain quantification of an 80bp "short" DNA fragment and a 207bp "long" DNA fragment in a degraded DNA sample in the multiplex system InnoQuant™. The ratio of the two quantitation values provides a "Degradation Index", or a qualitative measure of a sample's extent of degradation. The Degradation Index was found to be predictive of the observed loss

  13. Quantitative DNA Methylation Profiling in Cancer.

    Science.gov (United States)

    Ammerpohl, Ole; Haake, Andrea; Kolarova, Julia; Siebert, Reiner

    2016-01-01

    Epigenetic mechanisms including DNA methylation are fundamental for the regulation of gene expression. Epigenetic alterations can lead to the development and the evolution of malignant tumors as well as the emergence of phenotypically different cancer cells or metastasis from one single tumor cell. Here we describe bisulfite pyrosequencing, a technology to perform quantitative DNA methylation analyses, to detect aberrant DNA methylation in malignant tumors.

  14. Quantitative PCR for detection of DNA damage in mitochondrial DNA of the fission yeast Schizosaccharomyces pombe.

    Science.gov (United States)

    Senoo, Takanori; Yamanaka, Mayumi; Nakamura, Atori; Terashita, Tomoki; Kawano, Shinji; Ikeda, Shogo

    2016-08-01

    Quantitative polymerase chain reaction (QPCR) has been employed to detect DNA damage and repair in mitochondrial DNA (mtDNA) of human and several model organisms. The assay also permits the quantitation of relative mtDNA copy number in cells. Here, we developed the QPCR assay primers and reaction conditions for the fission yeast Schizosaccharomyces pombe, an important model of eukaryote biology, not previously described. Under these conditions, long targets (approximately 10kb) in mtDNA were quantitatively amplified using 0.1ng of crude DNA templates without isolation of mitochondria and mtDNA. Quantitative detection of oxidative DNA damage in mtDNA was illustrated by using a DNA template irradiated with UVA in the presence of riboflavin. The damage to mtDNA in S. pombe cells treated with hydrogen peroxide and paraquat was also quantitatively measured. Finally, we found that mtDNA copy number in S. pombe cells increased after transition into a stationary phase and that the damage to mtDNA due to endogenous cellular processes accumulated during chronological aging. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  16. Quantitative Real-Time PCR Analysis of YKL-40 and Its Comparison with Mammalian Chitinase mRNAs in Normal Human Tissues Using a Single Standard DNA

    Directory of Open Access Journals (Sweden)

    Misa Ohno

    2015-04-01

    Full Text Available YKL-40 (YKL for the first three N-terminal residues of a 40 kDa protein belongs to a group of human chitinase-like proteins (CLPs, which are similar to chitinases but lack chitinolytic activity. YKL-40 mRNA and its protein levels have been reported elevated in multiple disorders including asthma, cystic fibrosis, rheumatoid arthritis and malignant tumors. Here, we quantified the YKL-40 mRNA levels and compared them with chitinases and housekeeping genes in normal human tissues. To establish the quantitative real-time PCR (qPCR system for evaluation of relative YKL-40 mRNA levels, we constructed a human standard DNA molecule by ligating cDNAs of YKL-40, two mammalian chitinases and two housekeeping genes in a one-to-one ratio. We generated cDNAs from various normal human tissues and analyzed the YKL-40 mRNA expression levels using a qPCR system with the standard DNA. We found that YKL-40 mRNA is present widely in human tissues while its expression patterns exhibit clear tissue specificity. Highest YKL-40 mRNA levels were detected in the liver, followed by kidney, trachea and lung. The levels of YKL-40 mRNA in the kidney and liver were more than 100-times higher than those of chitotriosidase mRNA. Our study provides for the first time a comprehensive analysis of the relative expression levels of YKL-40 mRNA versus mammalian chitinases in normal human tissues.

  17. Quantitative analysis of human behavior.

    Science.gov (United States)

    Iacovitti, G

    2010-01-01

    Many aspects of individual as well as social behaviours of human beings can be analyzed in a quantitative way using typical scientific methods, based on empirical measurements and mathematical inference. Measurements are made possible today by the large variety of sensing devices, while formal models are synthesized using modern system and information theories.

  18. Quantitative analysis of human immunodeficiency virus type 1 DNA dynamics by real-time PCR: integration efficiency in stimulated and unstimulated peripheral blood mononuclear cells.

    Science.gov (United States)

    Suzuki, Youichi; Misawa, Naoko; Sato, Chihiro; Ebina, Hirotaka; Masuda, Takao; Yamamoto, Naoki; Koyanagi, Yoshio

    2003-10-01

    We established a set of real-time PCR assay to accurately quantify human immunodeficiency virus type 1 (HIV-1) DNA in infected cells. Using this assay we were able to measure the strong-stop, full-length/ 1-LTR circle, 2-LTR circle, and integrated forms of viral DNA, and the data provided was quite consistent with the characteristics of mutant viruses in early phase of infection. Since our assay is particularly applicable to quantify the integrated DNA in small scale of samples, we measured the level of integrated DNA in wild-type virus (WT)- or Vpr-defective virus (deltaVpr)-infected peripheral blood mononuclear cells (PBMC), and examined whether quiescent condition of the PBMC influences integration step of HIV-1. Under stimulating condition approximately 25% of total viral DNA was in integrated form in either WT- or DeltaVpr-infected cells. In contrast, under unstimulated condition the level of integration efficiency was not significantly reduced in WT-infected cells, while this efficiency was severely impaired in the absence of vpr gene. This result clearly demonstrated a crucial role of the Vpr for nuclear localization and subsequent integration of viral DNA in nondividing cells. Therefore, our assay is useful for analyzing the events in early phase of HIV-1 infection under various conditions.

  19. Quantitative Analysis of Mitochondrial DNA 4977-bp Deletion in Sporadic Breast Cancer and Benign Breast Tumors

    OpenAIRE

    Ye, Chuanzhong; Shu, Xiao-Ou; Wen, Wanqing; Pierce, Larry; Courtney, Regina; Gao, Yu-Tang; Zheng, Wei; Cai, Qiuyin

    2007-01-01

    The mitochondrial DNA (mtDNA) 4977-bp deletion (ΔmtDNA4977 mutation) is one of the most frequently observed mtDNA mutations in human tissues, and may play a role in carcinogenesis. Only a few studies have evaluated ΔmtDNA4977 mutation in breast cancer tissue, and the findings have been inconsistent, which may be due to methodological differences. In this study, we developed a quantitative real-time PCR assay to assess the level of the ΔmtDNA4977 mutation in tumor tissue samples from 55 primar...

  20. Comparison of proteases in DNA extraction via quantitative polymerase chain reaction.

    Science.gov (United States)

    Eychner, Alison M; Lebo, Roberta J; Elkins, Kelly M

    2015-06-01

    We compared four proteases in the QIAamp DNA Investigator Kit (Qiagen) to extract DNA for use in multiplex polymerase chain reaction (PCR) assays. The aim was to evaluate alternate proteases for improved DNA recovery as compared with proteinase K for forensic, biochemical research, genetic paternity and immigration, and molecular diagnostic purposes. The Quantifiler Kit TaqMan quantitative PCR assay was used to measure the recovery of DNA from human blood, semen, buccal cells, breastmilk, and earwax in addition to low-template samples, including diluted samples, computer keyboard swabs, chewing gum, and cigarette butts. All methods yielded amplifiable DNA from all samples. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Comparison of Six DNA Extraction Methods for Recovery of Fungal DNA as Assessed by Quantitative PCR

    OpenAIRE

    Fredricks, David N.; Smith, Caitlin; Meier, Amalia

    2005-01-01

    The detection of fungal pathogens in clinical samples by PCR requires the use of extraction methods that efficiently lyse fungal cells and recover DNA suitable for amplification. We used quantitative PCR assays to measure the recovery of DNA from two important fungal pathogens subjected to six DNA extraction methods. Aspergillus fumigatus conidia or Candida albicans yeast cells were added to bronchoalveolar lavage fluid and subjected to DNA extraction in order to assess the recovery of DNA fr...

  2. Is Quantitative HBsAg Measurement a Reliable Substitute for HBV DNA Quantitation?

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Mahdavi

    2015-07-01

    Conclusion: There are many factors affecting the correlation between serum HBV DNA copy number and HBsAg level such as genotype of HBV virus, phase of infection, methods of measurement, HBeAg status, and drug and types of treatment procedures. Therefore, these factors should be considered in further studies dealing with the correlation between quantitative HBV DNA and HBsAg tests.

  3. Rapid quantitative PCR assays for the simultaneous detection of herpes simplex virus, varicella zoster virus, cytomegalovirus, Epstein-Barr virus, and human herpesvirus 6 DNA in blood and other clinical specimens

    NARCIS (Netherlands)

    Engelmann, I.; Petzold, D. R.; Kosinska, A.; Hepkema, B. G.; Schulz, T. F.; Heim, A.

    Rapid diagnosis of human herpesvirus primary infections or reactivations is facilitated by quantitative PCRs. Quantitative PCR assays with a standard thermal cycling profile permitting simultaneous detection of herpes simplex virus (HSV), varicella zoster virus (VZV), cytomegalovirus (CMV),

  4. Spectroscopic Tools for Quantitative Studies of DNA Structure and Dynamics

    DEFF Research Database (Denmark)

    Preus, Søren

    The main objective of this thesis is to develop quantitative fluorescence-based, spectroscopic tools for probing the 3D structure and dynamics of DNA and RNA. The thesis is founded on six peer-reviewed papers covering mainly the development, characterization and use of fluorescent nucleobase...

  5. Quantitative fluorescence correlation spectroscopy on DNA in living cells

    Science.gov (United States)

    Hodges, Cameron; Kafle, Rudra P.; Meiners, Jens-Christian

    2017-02-01

    FCS is a fluorescence technique conventionally used to study the kinetics of fluorescent molecules in a dilute solution. Being a non-invasive technique, it is now drawing increasing interest for the study of more complex systems like the dynamics of DNA or proteins in living cells. Unlike an ordinary dye solution, the dynamics of macromolecules like proteins or entangled DNA in crowded environments is often slow and subdiffusive in nature. This in turn leads to longer residence times of the attached fluorophores in the excitation volume of the microscope and artifacts from photobleaching abound that can easily obscure the signature of the molecular dynamics of interest and make quantitative analysis challenging.We discuss methods and procedures to make FCS applicable to quantitative studies of the dynamics of DNA in live prokaryotic and eukaryotic cells. The intensity autocorrelation is computed function from weighted arrival times of the photons on the detector that maximizes the information content while simultaneously correcting for the effect of photobleaching to yield an autocorrelation function that reflects only the underlying dynamics of the sample. This autocorrelation function in turn is used to calculate the mean square displacement of the fluorophores attached to DNA. The displacement data is more amenable to further quantitative analysis than the raw correlation functions. By using a suitable integral transform of the mean square displacement, we can then determine the viscoelastic moduli of the DNA in its cellular environment. The entire analysis procedure is extensively calibrated and validated using model systems and computational simulations.

  6. Spectroscopic Tools for Quantitative Studies of DNA Structure and Dynamics

    DEFF Research Database (Denmark)

    Preus, Søren

    The main objective of this thesis is to develop quantitative fluorescence-based, spectroscopic tools for probing the 3D structure and dynamics of DNA and RNA. The thesis is founded on six peer-reviewed papers covering mainly the development, characterization and use of fluorescent nucleobase anal...... analogues. In addition, four software packages is presented for the simulation and quantitative analysis of time-resolved and steady-state UV-Vis absorption and fluorescence experiments.......The main objective of this thesis is to develop quantitative fluorescence-based, spectroscopic tools for probing the 3D structure and dynamics of DNA and RNA. The thesis is founded on six peer-reviewed papers covering mainly the development, characterization and use of fluorescent nucleobase...

  7. Human T-lymphotropic virus type 1 (HTLV-1 prevalence and quantitative detection of DNA proviral load in individuals with indeterminate/positive serological results

    Directory of Open Access Journals (Sweden)

    Bon Isabella

    2006-03-01

    Full Text Available Abstract Background HTLV-1 infection is currently restricted to endemic areas. To define the prevalence of HTLV-1 infection in patients living in Italy, we first carried out a retrospective serological analysis in a group of people originating from African countries referred to our hospital from January 2003 to February 2005. We subsequently applied a real time PCR on peripheral blood mononuclear cells from subjects with positive or indeterminate serological results. Methods All the sera were first analysed by serological methods (ELISA and/or Western Blotting and then the peripheral blood mononuclear cells from subjects with positive or inconclusive serological results were analyzed for the presence of proviral DNA by a sensitive SYBR Green real time PCR. In addition, twenty HTLV-I ELISA negative samples were assayed by real time PCR approach as negative controls. Results Serological results disclosed serum reactivity by ELISA (absorbance values equal or greater than the cut-off value in 9 out of 3408 individuals attending the Sexually Transmitted Diseases Clinic and/or Oncology Department, and 2 out 534 blood donors enrolled as a control population. Irrespective of positive or inconclusive serological results, all these subjects were analyzed for the presence of proviral DNA in peripheral blood mononuclear cells by SYBR real time PCR. A clear-cut positive result for the presence of HTLV-1 DNA was obtained in two subjects from endemic areas. Conclusion SYBR real time PCR cut short inconclusive serological results. This rapid and inexpensive assay showed an excellent linear dynamic range, specificity and reproducibility readily revealing and quantifying the presence of virus in PBMCs. Our results highlight the need to monitor the presence of HTLV-1 in countries which have seen a large influx of immigrants in recent years. Epidemiological surveillance and correct diagnosis are recommended to verify the prevalence and incidence of a new

  8. Delineating Rearrangements in Single Yeast Artificial Chromosomes by Quantitative DNA Fiber Mapping

    Energy Technology Data Exchange (ETDEWEB)

    Weier, Heinz-Ulrich G.; Greulich-Bode, Karin M.; Wu, Jenny; Duell, Thomas

    2009-09-18

    Cloning of large chunks of human genomic DNA in recombinant systems such as yeast or bacterial artificial chromosomes has greatly facilitated the construction of physical maps, the positional cloning of disease genes or the preparation of patient-specific DNA probes for diagnostic purposes. For this process to work efficiently, the DNA cloning process and subsequent clone propagation need to maintain stable inserts that are neither deleted nor otherwise rearranged. Some regions of the human genome; however, appear to have a higher propensity than others to rearrange in any host system. Thus, techniques to detect and accurately characterize such rearrangements need to be developed. We developed a technique termed 'Quantitative DNA Fiber Mapping (QDFM)' that allows accurate tagging of sequence elements of interest with near kilobase accuracy and optimized it for delineation of rearrangements in recombinant DNA clones. This paper demonstrates the power of this microscopic approach by investigating YAC rearrangements. In our examples, high-resolution physical maps for regions within the immunoglobulin lambda variant gene cluster were constructed for three different YAC clones carrying deletions of 95 kb and more. Rearrangements within YACs could be demonstrated unambiguously by pairwise mapping of cosmids along YAC DNA molecules. When coverage by YAC clones was not available, distances between cosmid clones were estimated by hybridization of cosmids onto DNA fibers prepared from human genomic DNA. In addition, the QDFM technology provides essential information about clone stability facilitating closure of the maps of the human genome as well as those of model organisms.

  9. Subjective Quantitative Studies of Human Agency

    Science.gov (United States)

    Alkire, Sabina

    2005-01-01

    Amartya Sen's writings have articulated the importance of human agency, and identified the need for information on agency freedom to inform our evaluation of social arrangements. Many approaches to poverty reduction stress the need for empowerment. This paper reviews "subjective quantitative measures of human agency at the individual level." It…

  10. Quantitative modeling of transcription factor binding specificities using DNA shape.

    Science.gov (United States)

    Zhou, Tianyin; Shen, Ning; Yang, Lin; Abe, Namiko; Horton, John; Mann, Richard S; Bussemaker, Harmen J; Gordân, Raluca; Rohs, Remo

    2015-04-14

    DNA binding specificities of transcription factors (TFs) are a key component of gene regulatory processes. Underlying mechanisms that explain the highly specific binding of TFs to their genomic target sites are poorly understood. A better understanding of TF-DNA binding requires the ability to quantitatively model TF binding to accessible DNA as its basic step, before additional in vivo components can be considered. Traditionally, these models were built based on nucleotide sequence. Here, we integrated 3D DNA shape information derived with a high-throughput approach into the modeling of TF binding specificities. Using support vector regression, we trained quantitative models of TF binding specificity based on protein binding microarray (PBM) data for 68 mammalian TFs. The evaluation of our models included cross-validation on specific PBM array designs, testing across different PBM array designs, and using PBM-trained models to predict relative binding affinities derived from in vitro selection combined with deep sequencing (SELEX-seq). Our results showed that shape-augmented models compared favorably to sequence-based models. Although both k-mer and DNA shape features can encode interdependencies between nucleotide positions of the binding site, using DNA shape features reduced the dimensionality of the feature space. In addition, analyzing the feature weights of DNA shape-augmented models uncovered TF family-specific structural readout mechanisms that were not revealed by the DNA sequence. As such, this work combines knowledge from structural biology and genomics, and suggests a new path toward understanding TF binding and genome function.

  11. Development of a real time polymerase chain reaction for quantitation of Schistosoma mansoni DNA

    Directory of Open Access Journals (Sweden)

    Ana Lisa do Vale Gomes

    2006-10-01

    Full Text Available This report describes the development of a SYBR Green I based real time polymerase chain reaction (PCR protocol for detection on the ABI Prism 7000 instrument. Primers targeting the gene encoding the SSU rRNA were designed to amplify with high specificity DNA from Schistosoma mansoni, in a real time quantitative PCR system. The limit of detection of parasite DNA for the system was 10 fg of purified genomic DNA, that means less than the equivalent to one parasite cell (genome ~580 fg DNA. The efficiency was 0.99 and the correlation coefficient (R² was 0.97. When different copy numbers of the target amplicon were used as standards, the assay could detect at least 10 copies of the specific target. The primers used were designed to amplify a 106 bp DNA fragment (Tm 83ºC. The assay was highly specific for S. mansoni, and did not recognize DNA from closely related non-schistosome trematodes. The real time PCR allowed for accurate quantification of S. mansoni DNA and no time-consuming post-PCR detection of amplification products by gel electrophoresis was required. The assay is potentially able to quantify S. mansoni DNA (and indirectly parasite burden in a number of samples, such as snail tissue, serum and feces from patients, and cercaria infested water. Thus, these PCR protocols have potential to be used as tools for monitoring of schistosome transmission and quantitative diagnosis of human infection.

  12. Quantitative allele-specific expression and DNA methylation analysis of H19, IGF2 and IGF2R in the human placenta across gestation reveals H19 imprinting plasticity.

    Directory of Open Access Journals (Sweden)

    Sam Buckberry

    Full Text Available Imprinted genes play important roles in placental differentiation, growth and function, with profound effects on fetal development. In humans, H19 and IGF2 are imprinted, but imprinting of IGF2R remains controversial. The H19 non-coding RNA is a negative regulator of placental growth and altered placental imprinting of H19-IGF2 has been associated with pregnancy complications such as preeclampsia, which have been attributed to abnormal first trimester placentation. This suggests that changes in imprinting during the first trimester may precede aberrant placental morphogenesis. To better understand imprinting in the human placenta during early gestation, we quantified allele-specific expression for H19, IGF2 and IGF2R in first trimester (6-12 weeks gestation and term placentae (37-42 weeks gestation using pyrosequencing. Expression of IGF2R was biallelic, with a mean expression ratio of 49:51 (SD = 0.07, making transient imprinting unlikely. Expression from the repressed H19 alleles ranged from 1-25% and was higher (P<0.001 in first trimester (13.5 ± 8.2% compared to term (3.4 ± 2.1% placentae. Surprisingly, despite the known co-regulation of H19 and IGF2, little variation in expression of the repressed IGF2 alleles was observed (2.7 ± 2.0%. To identify regulatory regions that may be responsible for variation in H19 allelic expression, we quantified DNA methylation in the H19-IGF2 imprinting control region and H19 transcription start site (TSS. Unexpectedly, we found positive correlations (P<0.01 between DNA methylation levels and expression of the repressed H19 allele at 5 CpG's 2000 bp upstream of the H19 TSS. Additionally, DNA methylation was significantly higher (P<0.05 in first trimester compared with term placentae at 5 CpG's 39-523 bp upstream of the TSS, but was not correlated with H19 repressed allele expression. Our data suggest that variation in H19 imprinting may contribute to early programming of placental phenotype and illustrate

  13. Understanding human DNA sequence variation.

    Science.gov (United States)

    Kidd, K K; Pakstis, A J; Speed, W C; Kidd, J R

    2004-01-01

    Over the past century researchers have identified normal genetic variation and studied that variation in diverse human populations to determine the amounts and distributions of that variation. That information is being used to develop an understanding of the demographic histories of the different populations and the species as a whole, among other studies. With the advent of DNA-based markers in the last quarter century, these studies have accelerated. One of the challenges for the next century is to understand that variation. One component of that understanding will be population genetics. We present here examples of many of the ways these new data can be analyzed from a population perspective using results from our laboratory on multiple individual DNA-based polymorphisms, many clustered in haplotypes, studied in multiple populations representing all major geographic regions of the world. These data support an "out of Africa" hypothesis for human dispersal around the world and begin to refine the understanding of population structures and genetic relationships. We are also developing baseline information against which we can compare findings at different loci to aid in the identification of loci subject, now and in the past, to selection (directional or balancing). We do not yet have a comprehensive understanding of the extensive variation in the human genome, but some of that understanding is coming from population genetics.

  14. Quantitative proteomic analysis of yeast DNA replication proteins.

    Science.gov (United States)

    Kubota, Takashi; Stead, David A; Hiraga, Shin-ichiro; ten Have, Sara; Donaldson, Anne D

    2012-06-01

    Chromatin is dynamically regulated, and proteomic analysis of its composition can provide important information about chromatin functional components. Many DNA replication proteins for example bind chromatin at specific times during the cell cycle. Proteomic investigation can also be used to characterize changes in chromatin composition in response to perturbations such as DNA damage, while useful information is obtained by testing the effects on chromatin composition of mutations in chromosome stability pathways. We have successfully used the method of stable isotope labeling by amino acids in cell culture (SILAC) for quantitative proteomic analysis of normal and pathological changes to yeast chromatin. Here we describe this proteomic method for analyzing changes to Saccharomyces cerevisiae chromatin, illustrating the procedure with an analysis of the changes that occur in chromatin composition as cells progress from a G1 phase block (induced by alpha factor) into S phase (in the presence of DNA replication inhibitor hydroxyurea). Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Science.gov (United States)

    Siegel, Erin M; Riggs, Bridget M; Delmas, Amber L; Koch, Abby; Hakam, Ardeshir; Brown, Kevin D

    2015-01-01

    Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2). A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site) per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC) of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003). Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

  16. Quantitative DNA methylation analysis of candidate genes in cervical cancer.

    Directory of Open Access Journals (Sweden)

    Erin M Siegel

    Full Text Available Aberrant DNA methylation has been observed in cervical cancer; however, most studies have used non-quantitative approaches to measure DNA methylation. The objective of this study was to quantify methylation within a select panel of genes previously identified as targets for epigenetic silencing in cervical cancer and to identify genes with elevated methylation that can distinguish cancer from normal cervical tissues. We identified 49 women with invasive squamous cell cancer of the cervix and 22 women with normal cytology specimens. Bisulfite-modified genomic DNA was amplified and quantitative pyrosequencing completed for 10 genes (APC, CCNA, CDH1, CDH13, WIF1, TIMP3, DAPK1, RARB, FHIT, and SLIT2. A Methylation Index was calculated as the mean percent methylation across all CpG sites analyzed per gene (~4-9 CpG site per sequence. A binary cut-point was defined at >15% methylation. Sensitivity, specificity and area under ROC curve (AUC of methylation in individual genes or a panel was examined. The median methylation index was significantly higher in cases compared to controls in 8 genes, whereas there was no difference in median methylation for 2 genes. Compared to HPV and age, the combination of DNA methylation level of DAPK1, SLIT2, WIF1 and RARB with HPV and age significantly improved the AUC from 0.79 to 0.99 (95% CI: 0.97-1.00, p-value = 0.003. Pyrosequencing analysis confirmed that several genes are common targets for aberrant methylation in cervical cancer and DNA methylation level of four genes appears to increase specificity to identify cancer compared to HPV detection alone. Alterations in DNA methylation of specific genes in cervical cancers, such as DAPK1, RARB, WIF1, and SLIT2, may also occur early in cervical carcinogenesis and should be evaluated.

  17. Freezing fecal samples prior to DNA extraction affects the Firmicutes to Bacteroidetes ratio determined by downstream quantitative PCR analysis

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Bergström, Anders; Licht, Tine Rask

    Freezing stool samples prior to DNA extraction and downstream analysis is widely used in metagenomic studies of the human microbiota but may affect the inferred community composition. In this study DNA was extracted either directly or following freeze storage of three homogenized human fecal...... samples using three different extraction methods. No consistent differences were observed in DNA yields between extractions on fresh and frozen samples, however differences were observed between extraction methods. Quantitative PCR analysis was subsequently performed on all DNA samples using six different...

  18. Freezing fecal samples prior to DNA extraction affects the Firmicutes to Bacteroidetes ratio determined by downstream quantitative PCR analysis

    DEFF Research Database (Denmark)

    Bahl, Martin Iain; Bergström, Anders; Licht, Tine Rask

    2012-01-01

    Freezing stool samples prior to DNA extraction and downstream analysis is widely used in metagenomic studies of the human microbiota but may affect the inferred community composition. In this study, DNA was extracted either directly or following freeze storage of three homogenized human fecal...... samples using three different extraction methods. No consistent differences were observed in DNA yields between extractions on fresh and frozen samples; however, differences were observed between extraction methods. Quantitative PCR analysis was subsequently performed on all DNA samples using six...

  19. Human Rap1 modulates TRF2 attraction to telomeric DNA.

    Science.gov (United States)

    Janoušková, Eliška; Nečasová, Ivona; Pavloušková, Jana; Zimmermann, Michal; Hluchý, Milan; Marini, Victoria; Nováková, Monika; Hofr, Ctirad

    2015-03-11

    More than two decades of genetic research have identified and assigned main biological functions of shelterin proteins that safeguard telomeres. However, a molecular mechanism of how each protein subunit contributes to the protecting function of the whole shelterin complex remains elusive. Human Repressor activator protein 1 (Rap1) forms a multifunctional complex with Telomeric Repeat binding Factor 2 (TRF2). Rap1-TRF2 complex is a critical part of shelterin as it suppresses homology-directed repair in Ku 70/80 heterodimer absence. To understand how Rap1 affects key functions of TRF2, we investigated full-length Rap1 binding to TRF2 and Rap1-TRF2 complex interactions with double-stranded DNA by quantitative biochemical approaches. We observed that Rap1 reduces the overall DNA duplex binding affinity of TRF2 but increases the selectivity of TRF2 to telomeric DNA. Additionally, we observed that Rap1 induces a partial release of TRF2 from DNA duplex. The improved TRF2 selectivity to telomeric DNA is caused by less pronounced electrostatic attractions between TRF2 and DNA in Rap1 presence. Thus, Rap1 prompts more accurate and selective TRF2 recognition of telomeric DNA and TRF2 localization on single/double-strand DNA junctions. These quantitative functional studies contribute to the understanding of the selective recognition of telomeric DNA by the whole shelterin complex. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  20. DNA Methylation Landscapes of Human Fetal Development

    NARCIS (Netherlands)

    Slieker, Roderick C; Roost, Matthias S; van Iperen, Liesbeth; Suchiman, H Eka D; Tobi, Elmar W; Carlotti, Françoise; de Koning, Eelco J P; Slagboom, P Eline; Heijmans, Bastiaan T; Chuva de Sousa Lopes, Susana M

    2015-01-01

    Remodelling the methylome is a hallmark of mammalian development and cell differentiation. However, current knowledge of DNA methylation dynamics in human tissue specification and organ development largely stems from the extrapolation of studies in vitro and animal models. Here, we report on the DNA

  1. Visual characterization and quantitative measurement of artemisinin-induced DNA breakage

    Energy Technology Data Exchange (ETDEWEB)

    Cai Huaihong [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China); Yang Peihui [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China)], E-mail: typh@jnu.edu.cn; Chen Jianan [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China); Liang Zhihong [Experiment and Technology Center, Jinan University, Guangzhou 510632 (China); Chen Qiongyu [Institute of Genetic Engineering, Jinan University, Guangzhou 510632 (China); Cai Jiye [Bionanotechnology Lab, and Department of Chemistry, Jinan University, Guangzhou 510632 (China)], E-mail: tjycai@jnu.edu.cn

    2009-05-01

    DNA conformational change and breakage induced by artemisinin, a traditional Chinese herbal medicine, have been visually characterized and quantitatively measured by the multiple tools of electrochemistry, UV-vis absorption spectroscopy, atomic force microscopy (AFM), and DNA electrophoresis. Electrochemical and spectroscopic results confirm that artemisinin can intercalate into DNA double helix, which causes DNA conformational changes. AFM imaging vividly demonstrates uneven DNA strand breaking induced by QHS interaction. To assess these DNA breakages, quantitative analysis of the extent of DNA breakage has been performed by analyzing AFM images. Basing on the statistical analysis, the occurrence of DNA breaks is found to depend on the concentration of artemisinin. DNA electrophoresis further validates that the intact DNA molecules are unwound due to the breakages occur at the single strands. A reliable scheme is proposed to explain the process of artemisinin-induced DNA cleavage. These results can provide further information for better understanding the anticancer activity of artemisinin.

  2. Human DNA Ligase III Recognizes DNA Ends by Dynamic Switching Between Two DNA Bound States†

    OpenAIRE

    Cotner-Gohara, Elizabeth; Kim, In-Kwon; Hammel, Michal; Tainer, John A.; Tomkinson, Alan E.; Ellenberger, Tom

    2010-01-01

    Human DNA ligase III has essential functions in nuclear and mitochondrial DNA replication and repair and contains a PARP-like zinc finger (ZnF) that increases DNA nick-joining and intermolecular DNA ligation. Yet, the bases for ligase III specificity and structural variation among human ligases are not understood. Here combined crystal structure and small angle x-ray scattering results reveal dynamic switching between two nick-binding components of ligase III: the ZnF-DNA binding domain (DBD)...

  3. A Quantitative Tool for Producing DNA-Based Diagnostic Arrays

    Energy Technology Data Exchange (ETDEWEB)

    Tom J. Whitaker

    2008-07-11

    The purpose of this project was to develop a precise, quantitative method to analyze oligodeoxynucleotides (ODNs) on an array to enable a systematic approach to quality control issues affecting DNA microarrays. Two types of ODN's were tested; ODN's formed by photolithography and ODN's printed onto microarrays. Initial work in Phase I, performed in conjunction with Affymetrix, Inc. who has a patent on a photolithographic in situ technique for creating DNA arrays, was very promising but did seem to indicate that the atomization process was not complete. Soon after Phase II work was under way, Affymetrix had further developed fluorescent methods and indicated they were no longer interested in our resonance ionization technique. This was communicated to the program manager and it was decided that the project would continue and be focused on printed ODNs. The method being tested is called SIRIS, Sputter-Initiated Resonance Ionization Spectroscopy. SIRIS has been shown to be a highly sensitive, selective, and quantitative tool for atomic species. This project was aimed at determining if an ODN could be labeled in such a way that SIRIS could be used to measure the label and thus provide quantitative measurements of the ODN on an array. One of the largest problems in this study has been developing a method that allows us to know the amount of an ODN on a surface independent of the SIRIS measurement. Even though we could accurately determine the amount of ODN deposited on a surface, the amount that actually attached to the surface is very difficult to measure (hence the need for a quantitative tool). A double-labeling procedure was developed in which 33P and Pt were both used to label ODNs. The radioactive 33P could be measured by a proportional counter that maps the counts in one dimension. This gave a good measurement of the amount of ODN remaining on a surface after immobilization and washing. A second label, Pt, was attached to guanine nucleotides in the

  4. Universal platform for quantitative analysis of DNA transposition

    Directory of Open Access Journals (Sweden)

    Pajunen Maria I

    2010-11-01

    Full Text Available Abstract Background Completed genome projects have revealed an astonishing diversity of transposable genetic elements, implying the existence of novel element families yet to be discovered from diverse life forms. Concurrently, several better understood transposon systems have been exploited as efficient tools in molecular biology and genomics applications. Characterization of new mobile elements and improvement of the existing transposition technology platforms warrant easy-to-use assays for the quantitative analysis of DNA transposition. Results Here we developed a universal in vivo platform for the analysis of transposition frequency with class II mobile elements, i.e., DNA transposons. For each particular transposon system, cloning of the transposon ends and the cognate transposase gene, in three consecutive steps, generates a multifunctional plasmid, which drives inducible expression of the transposase gene and includes a mobilisable lacZ-containing reporter transposon. The assay scores transposition events as blue microcolonies, papillae, growing within otherwise whitish Escherichia coli colonies on indicator plates. We developed the assay using phage Mu transposition as a test model and validated the platform using various MuA transposase mutants. For further validation and to illustrate universality, we introduced IS903 transposition system components into the assay. The developed assay is adjustable to a desired level of initial transposition via the control of a plasmid-borne E. coli arabinose promoter. In practice, the transposition frequency is modulated by varying the concentration of arabinose or glucose in the growth medium. We show that variable levels of transpositional activity can be analysed, thus enabling straightforward screens for hyper- or hypoactive transposase mutants, regardless of the original wild-type activity level. Conclusions The established universal papillation assay platform should be widely applicable to a

  5. Quantitative Profiling of DNA Damage and Apoptotic Pathways in UV Damaged Cells Using PTMScan Direct

    Directory of Open Access Journals (Sweden)

    Roberto D. Polakiewicz

    2012-12-01

    Full Text Available Traditional methods for analysis of peptides using liquid chromatography and tandem mass spectrometry (LC-MS/MS lack the specificity to comprehensively monitor specific biological processes due to the inherent duty cycle limitations of the MS instrument and the stochastic nature of the analytical platform. PTMScan Direct is a novel, antibody-based method that allows quantitative LC-MS/MS profiling of specific peptides from proteins that reside in the same signaling pathway. New PTMScan Direct reagents have been produced that target peptides from proteins involved in DNA Damage/Cell Cycle and Apoptosis/Autophagy pathways. Together, the reagents provide access to 438 sites on 237 proteins in these signaling cascades. These reagents have been used to profile the response to UV damage of DNA in human cell lines. UV damage was shown to activate canonical DNA damage response pathways through ATM/ATR-dependent signaling, stress response pathways and induce the initiation of apoptosis, as assessed by an increase in the abundance of peptides corresponding to cleaved, activated caspases. These data demonstrate the utility of PTMScan Direct as a multiplexed assay for profiling specific cellular responses to various stimuli, such as UV damage of DNA.

  6. Perinatal transmission of human papilomavirus DNA.

    Science.gov (United States)

    Rombaldi, Renato L; Serafini, Eduardo P; Mandelli, Jovana; Zimmermann, Edineia; Losquiavo, Kamille P

    2009-06-21

    The purpose was to study the perinatal transmission of human papillomavirus DNA (HPV-DNA) in 63 mother-newborn pairs, besides looking at the epidemiological factors involved in the viral DNA transmission. The following sampling methods were used: (1) in the pregnant woman, when was recruited, in cervix and clinical lesions of the vagina, vulva and perineal region; (2) in the newborn, (a) buccal, axillary and inguinal regions; (b) nasopharyngeal aspirate, and (c) cord blood; (3) in the children, buccal was repeated in the 4th week and 6th and 12th month of life. HPV-DNA was identified using two methodologies: multiplex PCR (PGMY09 and MY11 primers) and nested-PCR (genotypes 6/11, 16, 18, 31, 33, 42, 52 and 58). Perinatal transmission was considered when concordance was found in type-specific HPV between mother/newborn or mother/child. HPV-DNA genital was detected in 49 pregnant women submitted to delivery. Eleven newborns (22.4%, n = 11/49) were HPV-DNA positive. In 8 cases (16.3%, n = 8/49) there was type specific HPV concordance between mother/newborn samples. At the end of the first month of life three children (6.1%, n = 3/49) became HPV-DNA positive, while two remained positive from birth. In 3 cases (100%, n = 3/3) there was type specific HPV concordance between mother/newborn samples. In the 6th month, a child (2%, n = 1/49) had become HPV-DNA positive between the 1st and 6th month of life, and there was type specific HPV concordance of mother/newborn samples. All the HPV-DNA positive children (22.4%, n = 11/49) at birth and at the end first month of life (6.1%, n = 3/49) became HPV-DNA negative at the age of 6 months. The HPV-DNA positive child (2%, n = 1/49) from 1st to the 6th month of life became HPV-DNA negative between the 6th and 12th month of life and one child had anogenital warts. In the twelfth month all (100%, n = 49/49) the children studied were HPV-DNA negative. A positive and significant correlation was observed between perinatal transmission

  7. Perinatal transmission of human papilomavirus DNA

    Directory of Open Access Journals (Sweden)

    Serafini Eduardo P

    2009-06-01

    Full Text Available Abstract The purpose was to study the perinatal transmission of human papillomavirus DNA (HPV-DNA in 63 mother-newborn pairs, besides looking at the epidemiological factors involved in the viral DNA transmission. The following sampling methods were used: (1 in the pregnant woman, when was recruited, in cervix and clinical lesions of the vagina, vulva and perineal region; (2 in the newborn, (a buccal, axillary and inguinal regions; (b nasopharyngeal aspirate, and (c cord blood; (3 in the children, buccal was repeated in the 4th week and 6th and 12th month of life. HPV-DNA was identified using two methodologies: multiplex PCR (PGMY09 and MY11 primers and nested-PCR (genotypes 6/11, 16, 18, 31, 33, 42, 52 and 58. Perinatal transmission was considered when concordance was found in type-specific HPV between mother/newborn or mother/child. HPV-DNA genital was detected in 49 pregnant women submitted to delivery. Eleven newborns (22.4%, n = 11/49 were HPV-DNA positive. In 8 cases (16.3%, n = 8/49 there was type specific HPV concordance between mother/newborn samples. At the end of the first month of life three children (6.1%, n = 3/49 became HPV-DNA positive, while two remained positive from birth. In 3 cases (100%, n = 3/3 there was type specific HPV concordance between mother/newborn samples. In the 6th month, a child (2%, n = 1/49 had become HPV-DNA positive between the 1st and 6th month of life, and there was type specific HPV concordance of mother/newborn samples. All the HPV-DNA positive children (22.4%, n = 11/49 at birth and at the end first month of life (6.1%, n = 3/49 became HPV-DNA negative at the age of 6 months. The HPV-DNA positive child (2%, n = 1/49 from 1st to the 6th month of life became HPV-DNA negative between the 6th and 12th month of life and one child had anogenital warts. In the twelfth month all (100%, n = 49/49 the children studied were HPV-DNA negative. A positive and significant correlation was observed between perinatal

  8. Quantitation by flow microfluorometry of total cellular DNA in Acanthamoeba

    Energy Technology Data Exchange (ETDEWEB)

    Coulson, P.B.; Tyndall, R.

    1978-01-01

    The DNA content of five speciea of Acanthamoeba was determined by flow microfluorometry. Acanthamoeba castellanii (AC-30), acanthamoeba polyphaga (APG and P-23), acanthamoeba rhysodes, acanthamoeba culbertsoni (A-1), and acanthamoeba royreba were grown in a casitone based medium 24 to 48 hr. The trophozoites were harvested, fixed in 70% ethanol (acidified), pretreated with RNase, stained with propidium diiodide, and evaluated for DNA-bound fluorescence. All species tested had DNA values between 2.0 to 5.0 pg/cell. These results placed DNA/cell values of Acanthamoeba slightly lower than DNA/cell values of other eucaryotic cells and much lower than Amoeba proteus values. These results indicate that FMF may be a useful adjunct in distinguishing Acanthamoeba cells from either eucaryotic cells or some other amoeba. However, differences in DNA/cell between species of Acanthamoeba are small and would not be useful in identification of species.

  9. Bacterial DNA delays human eosinophil apoptosis

    OpenAIRE

    2009-01-01

    Bacterial DNA delays human eosinophil apoptosis correspondance: Corresponding author. Tel.: +358 3 3551 6687; fax: +358 3 3551 8082. (Ilmarinen, Pinja) (Ilmarinen, Pinja) The Immunopharmacology Research Group--> , Medical School--> , University of Tampere and Research Unit--> , Tampere University Hospital--> , Tampere--> - FINLAND (Ilmarinen, Pinja) The Immunopharmacology ...

  10. Human papillomavirus DNA in aerodigestive squamous carcinomas ...

    African Journals Online (AJOL)

    A series of 10 oesophageal and 10 laryngeal squamous carcinomas was examined by means of immuno cytochemistry and in situ DNA hybridisation to demonstrate human papillomavirus (HPV) infection. Changes in the epithelium adjacent to the carcinoma were found in 5 of 10 oesophageal and 7 of 10 laryngeal ...

  11. Quantitative measurement of ultraviolet-induced damage in cellular DNA by an enzyme immunodot assay

    Energy Technology Data Exchange (ETDEWEB)

    Wakizaka, A.; Nishizawa, Y.; Aiba, N.; Okuhara, E.; Takahashi, S.

    1989-02-01

    A simple enzyme immunoassay procedure was developed for the quantitative determination of 254-nm uv-induced DNA damage in cells. With the use of specific antibodies to uv-irradiated DNA and horseradish peroxidase-conjugated antibody to rabbit IgG, the extent of damaged DNA in uv-irradiated rat spleen mononuclear cells was quantitatively measurable. Through the use of this method, the amount of damaged DNA present in 2 X 10(5) cells irradiated at a dose of 75 J/m2 was estimated to be 7 ng equivalents of the standard uv-irradiated DNA. In addition, when the cells, irradiated at 750 J/m2, were incubated for 1 h, the antigenic activity of DNA decreased by 40%, suggesting that a repair of the damaged sites in DNA had proceeded to some extent in the cells.

  12. The near-quantitative sampling of genomic DNA from various food-borne Eubacteria

    National Research Council Canada - National Science Library

    Irwin, Peter; Nguyen, Ly; He, Yiping; Paoli, George; Gehring, Andrew; Chen, Chin-Yi

    2014-01-01

    The disruption of the bacterial cell wall plays an important part in achieving quantitative extraction of DNA from Eubacteria essential for accurate analyses of genetic material recovered from environmental samples...

  13. Extraction of DNA from Human Skeletal Material.

    Science.gov (United States)

    Pajnič, Irena Zupanič

    2016-01-01

    In recent years the recovery and analysis of DNA from skeletal remains has been applied to several contexts ranging from disaster victim identification to the identification of the victims of conflict. Here are described procedures for processing the bone and tooth samples including mechanical and chemical cleaning, cutting and powdering in the presence of liquid nitrogen, complete demineralization of bone and tooth powder, DNA extraction, DNA purification using magnetic beads, and the precautions and strategies implemented to avoid and detect contamination. It has proven highly successful in the analysis of bones and teeth from Second World War victims' skeletal remains that have been excavated from mass graves in Slovenia and is also suitable for genetic identification of relatively fresh human remains.

  14. Assessment of precision and concordance of quantitative mitochondrial DNA assays: a collaborative international quality assurance study

    NARCIS (Netherlands)

    Hammond, Emma L.; Sayer, David; Nolan, David; Walker, Ulrich A.; Ronde, Anthony de; Montaner, Julio S. G.; Cote, Helene C. F.; Gahan, Michelle E.; Cherry, Catherine L.; Wesselingh, Steven L.; Reiss, Peter; Mallal, Simon

    2003-01-01

    Background: A number of international research groups have developed DNA quantitation assays in order to investigate the role of mitochondrial DNA depletion in anti-retroviral therapy-induced toxicities. Objectives: A collaborative study was undertaken to evaluate intra-assay precision and between

  15. Isolation and Quantitation of Topoisomerase Complexes Accumulated on Escherichia coli Chromosomal DNA

    OpenAIRE

    Aedo, Sandra; Tse-Dinh, Yuk-Ching

    2012-01-01

    DNA topoisomerases are important targets in anticancer and antibacterial therapy because drugs can initiate cell death by stabilizing the transient covalent topoisomerase-DNA complex. In this study, we employed a method that uses CsCl density gradient centrifugation to separate unbound from DNA-bound GyrA/ParC in Escherichia coli cell lysates after quinolone treatment, allowing antibody detection and quantitation of the covalent complexes on slot blots. Using these procedures modified from th...

  16. Sex-specific regulation of mitochondrial DNA levels: genome-wide linkage analysis to identify quantitative trait loci.

    Science.gov (United States)

    López, Sonia; Buil, Alfonso; Souto, Juan Carlos; Casademont, Jordi; Blangero, John; Martinez-Perez, Angel; Fontcuberta, Jordi; Lathrop, Mark; Almasy, Laura; Soria, Jose Manuel

    2012-01-01

    Altered mitochondrial DNA (mtDNA) levels have been associated with common diseases in humans. We investigated the genetic mechanism that controls mtDNA levels using genome-wide linkage analyses in families from the Genetic Analysis of Idiopathic Thrombophilia Project (GAIT). We measure mtDNA levels by quantitative real-time PCR in 386 subjects from 21 extended Spanish families. A variance component linkage method using 485 microsatellites was conducted to evaluate linkage and to detect quantitative trait loci (QTLs) involved in the control of mtDNA levels. The heritalibility of mtDNA levels was 0.33 (p=1.82e-05). We identified a QTL on Chromosome 2 (LOD=2.21) using all of the subjects, independently on their sex. When females and males were analysed separately, three QTLs were identified. Females showed the same QTL on Chromosome 2 (LOD=3.09), indicating that the QTL identified in the analysis using all of the subjects was a strong female QTL, and another one on Chromosome 3 (LOD=2.67), whereas in males a QTL was identified on Chromosome 1 (LOD=2.81). These QTLs were fine-mapped to find associations with mtDNA levels. The most significant SNP association was for the rs10888838 on Chromosome 1 in males. This SNP mapped to the gene MRPL37, involved in mitochondrial protein translation. The rs2140855 on Chromosome 2 showed association in the analysis using all of the subjects. It was near the gene CMPK2, which encodes a mitochondrial enzyme of the salvage pathway of deoxyribonucleotide synthesis. Our results provide evidence of a sex-specific genetic mechanism for the control of mtDNA levels and provide a framework to identify new genes that influence mtDNA levels.

  17. Sex-specific regulation of mitochondrial DNA levels: genome-wide linkage analysis to identify quantitative trait loci.

    Directory of Open Access Journals (Sweden)

    Sonia López

    Full Text Available Altered mitochondrial DNA (mtDNA levels have been associated with common diseases in humans. We investigated the genetic mechanism that controls mtDNA levels using genome-wide linkage analyses in families from the Genetic Analysis of Idiopathic Thrombophilia Project (GAIT. We measure mtDNA levels by quantitative real-time PCR in 386 subjects from 21 extended Spanish families. A variance component linkage method using 485 microsatellites was conducted to evaluate linkage and to detect quantitative trait loci (QTLs involved in the control of mtDNA levels. The heritalibility of mtDNA levels was 0.33 (p=1.82e-05. We identified a QTL on Chromosome 2 (LOD=2.21 using all of the subjects, independently on their sex. When females and males were analysed separately, three QTLs were identified. Females showed the same QTL on Chromosome 2 (LOD=3.09, indicating that the QTL identified in the analysis using all of the subjects was a strong female QTL, and another one on Chromosome 3 (LOD=2.67, whereas in males a QTL was identified on Chromosome 1 (LOD=2.81. These QTLs were fine-mapped to find associations with mtDNA levels. The most significant SNP association was for the rs10888838 on Chromosome 1 in males. This SNP mapped to the gene MRPL37, involved in mitochondrial protein translation. The rs2140855 on Chromosome 2 showed association in the analysis using all of the subjects. It was near the gene CMPK2, which encodes a mitochondrial enzyme of the salvage pathway of deoxyribonucleotide synthesis. Our results provide evidence of a sex-specific genetic mechanism for the control of mtDNA levels and provide a framework to identify new genes that influence mtDNA levels.

  18. Quantitative MRI of the human brain at 7 tesla

    NARCIS (Netherlands)

    Polders, D.L.

    2012-01-01

    This thesis describes the implementation of quantitative MR methods in the human brain at 7 T. By highlighting the drawbacks and advantages of the increased field strength, the use of 7 T MRI for quantitative measurements in clinical research was demonstrated. Inhomogeneities in the transmitted RF

  19. Highly Rapid Amplification-Free and Quantitative DNA Imaging Assay

    Science.gov (United States)

    Klamp, Tobias; Camps, Marta; Nieto, Benjamin; Guasch, Francesc; Ranasinghe, Rohan T.; Wiedemann, Jens; Petrášek, Zdeněk; Schwille, Petra; Klenerman, David; Sauer, Markus

    2013-01-01

    There is an urgent need for rapid and highly sensitive detection of pathogen-derived DNA in a point-of-care (POC) device for diagnostics in hospitals and clinics. This device needs to work in a ‘sample-in-result-out’ mode with minimum number of steps so that it can be completely integrated into a cheap and simple instrument. We have developed a method that directly detects unamplified DNA, and demonstrate its sensitivity on realistically sized 5 kbp target DNA fragments of Micrococcus luteus in small sample volumes of 20 μL. The assay consists of capturing and accumulating of target DNA on magnetic beads with specific capture oligonucleotides, hybridization of complementary fluorescently labeled detection oligonucleotides, and fluorescence imaging on a miniaturized wide-field fluorescence microscope. Our simple method delivers results in less than 20 minutes with a limit of detection (LOD) of ~5 pM and a linear detection range spanning three orders of magnitude. PMID:23677392

  20. DNA methylation and healthy human aging.

    Science.gov (United States)

    Jones, Meaghan J; Goodman, Sarah J; Kobor, Michael S

    2015-12-01

    The process of aging results in a host of changes at the cellular and molecular levels, which include senescence, telomere shortening, and changes in gene expression. Epigenetic patterns also change over the lifespan, suggesting that epigenetic changes may constitute an important component of the aging process. The epigenetic mark that has been most highly studied is DNA methylation, the presence of methyl groups at CpG dinucleotides. These dinucleotides are often located near gene promoters and associate with gene expression levels. Early studies indicated that global levels of DNA methylation increase over the first few years of life and then decrease beginning in late adulthood. Recently, with the advent of microarray and next-generation sequencing technologies, increases in variability of DNA methylation with age have been observed, and a number of site-specific patterns have been identified. It has also been shown that certain CpG sites are highly associated with age, to the extent that prediction models using a small number of these sites can accurately predict the chronological age of the donor. Together, these observations point to the existence of two phenomena that both contribute to age-related DNA methylation changes: epigenetic drift and the epigenetic clock. In this review, we focus on healthy human aging throughout the lifetime and discuss the dynamics of DNA methylation as well as how interactions between the genome, environment, and the epigenome influence aging rates. We also discuss the impact of determining 'epigenetic age' for human health and outline some important caveats to existing and future studies. © 2015 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  1. A preliminary analysis of the DNA and diet of the extinct Beothuk: a systematic approach to ancient human DNA

    DEFF Research Database (Denmark)

    Kuch, Melanie; Gröcke, Darren R; Knyf, Martin C

    2007-01-01

    We have used a systematic protocol for extracting, quantitating, sexing and validating ancient human mitochondrial and nuclear DNA of one male and one female Beothuk, a Native American population from Newfoundland, which became extinct approximately 180 years ago. They carried mtDNA haplotypes......, which fall within haplogroups X and C, consistent with Northeastern Native populations today. In addition we have sexed the male using a novel-sexing assay and confirmed the authenticity of his Y chromosome with the presence of the Native American specific Y-QM3 single nucleotide polymorphism (SNP......, Nonosabasut) were of admixed (European-Native American) descent. We also analyzed patterns of DNA damage in the clones of authentic mtDNA sequences; there is no tendency for DNA damage to occur preferentially at previously defined mutational hotspots, suggesting that such mutational hotspots...

  2. The quantitative failure of human reliability analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C.T.

    1995-07-01

    This philosophical treatise argues the merits of Human Reliability Analysis (HRA) in the context of the nuclear power industry. Actually, the author attacks historic and current HRA as having failed in informing policy makers who make decisions based on risk that humans contribute to systems performance. He argues for an HRA based on Bayesian (fact-based) inferential statistics, which advocates a systems analysis process that employs cogent heuristics when using opinion, and tempers itself with a rational debate over the weight given subjective and empirical probabilities.

  3. The Cell Cycle Timing of Human Papillomavirus DNA Replication.

    Science.gov (United States)

    Reinson, Tormi; Henno, Liisi; Toots, Mart; Ustav, Mart; Ustav, Mart

    2015-01-01

    Viruses manipulate the cell cycle of the host cell to optimize conditions for more efficient viral genome replication. One strategy utilized by DNA viruses is to replicate their genomes non-concurrently with the host genome; in this case, the viral genome is amplified outside S phase. This phenomenon has also been described for human papillomavirus (HPV) vegetative genome replication, which occurs in G2-arrested cells; however, the precise timing of viral DNA replication during initial and stable replication phases has not been studied. We developed a new method to quantitate newly synthesized DNA levels and used this method in combination with cell cycle synchronization to show that viral DNA replication is initiated during S phase and is extended to G2 during initial amplification but follows the replication pattern of cellular DNA during S phase in the stable maintenance phase. E1 and E2 protein overexpression changes the replication time from S only to both the S and G2 phases in cells that stably maintain viral episomes. These data demonstrate that the active synthesis and replication of the HPV genome are extended into the G2 phase to amplify its copy number and the duration of HPV genome replication is controlled by the level of the viral replication proteins E1 and E2. Using the G2 phase for genome amplification may be an important adaptation that allows exploitation of changing cellular conditions during cell cycle progression. We also describe a new method to quantify newly synthesized viral DNA levels and discuss its benefits for HPV research.

  4. Comparison of DNA extraction kits and modification of DNA elution procedure for the quantitation of subdominant bacteria from piggery effluents with real‐time PCR

    National Research Council Canada - National Science Library

    Desneux, Jérémy; Pourcher, Anne‐Marie

    2014-01-01

    Four commercial DNA extraction kits and a minor modification in the DNA elution procedure were evaluated for the quantitation of bacteria in pig manure samples. The PowerSoil ® , PowerFecal ® , NucleoSpin...

  5. Identification of Streptococcus parasanguinis DNA contamination in human buccal DNA samples.

    Science.gov (United States)

    Mahfuz, Istiak; Cheng, Wei; White, Stefan J

    2013-11-22

    The use of buccal swabs in clinical and scientific studies is a very popular method of collecting DNA, due to its non-invasive nature of collection. However, contamination of the DNA sample may interfere with analysis. Here we report the finding of Streptococcus parasanguinis bacterial DNA contamination in human buccal DNA samples, which led to preferential amplification of bacterial sequence with PCR primers designed against human sequence. Contamination of buccal-derived DNA with bacterial DNA can be significant, and may influence downstream genetic analysis. One needs to be aware of possible bacterial contamination when interpreting abnormal findings following PCR amplification of buccal swab DNA samples.

  6. Conversion of cDNA differential display results (DDRT-PCR) into quantitative transcription profiles

    Science.gov (United States)

    Venkatesh, Balakrishnan; Hettwer, Ursula; Koopmann, Birger; Karlovsky, Petr

    2005-01-01

    Background Gene expression studies on non-model organisms require open-end strategies for transcription profiling. Gel-based analysis of cDNA fragments allows to detect alterations in gene expression for genes which have neither been sequenced yet nor are available in cDNA libraries. Commonly used protocols for gel-based transcript profiling are cDNA differential display (DDRT-PCR) and cDNA-AFLP. Both methods have been used merely as qualitative gene discovery tools so far. Results We developed procedures for the conversion of cDNA Differential Display data into quantitative transcription profiles. Amplified cDNA fragments are separated on a DNA sequencer and detector signals are converted into virtual gel images suitable for semi-automatic analysis. Data processing consists of four steps: (i) cDNA bands in lanes corresponding to samples treated with the same primer combination are matched in order to identify fragments originating from the same transcript, (ii) intensity of bands is determined by densitometry, (iii) densitometric values are normalized, and (iv) intensity ratio is calculated for each pair of corresponding bands. Transcription profiles are represented by sets of intensity ratios (control vs. treatment) for cDNA fragments defined by primer combination and DNA mobility. We demonstrated the procedure by analyzing DDRT-PCR data on the effect of secondary metabolites of oilseed rape Brassica napus on the transcriptome of the pathogenic fungus Leptosphaeria maculans. Conclusion We developed a data processing procedure for the quantitative analysis of amplified cDNA fragments separated by electrophoresis. The system utilizes common software and provides an open-end alternative to DNA microarray analysis of the transcriptome. It is expected to work equally well with DDRT-PCR and cDNA-AFLP data and be useful particularly in reseach on organisms for which microarray analysis is not available or economical. PMID:15807902

  7. Comparison of three different techniques of human sperm DNA isolation for methylation assay.

    Science.gov (United States)

    Yuan, Hong-fang; Kuete, Martin; Su, Li; Yang, Fan; Hu, Zhi-yong; Tian, Bo-zhen; Zhang, Hui-ping; Zhao, Kai

    2015-12-01

    Human sperm DNA is an important genetic and epigenetic material, whose chromatin structure differs from that of somatic cells. As such, conventional methods for DNA extraction of somatic cells may not be suitable for obtaining sperm DNA. In this study, we evaluated and compared three sperm DNA extraction techniques, namely, modified guanidinium thiocyanate method (method A), traditional phenol-chloroform method (method B), and TianGen kit method (method C). Spectrophotometry and agarose gel electrophoresis analyses showed that method A produced DNA with higher quantity and purity than those of methods B and C (Psperm DNA methylation assay further indicated that methods A and B were effective, and the former yielded higher quantitative accuracy. In conclusion, the modified guanidinium thiocyanate method provided high quality and reliable results and could be an optimal technique for extracting sperm DNA for methylation assay.

  8. A quantitative theory of human color choices.

    Science.gov (United States)

    Komarova, Natalia L; Jameson, Kimberly A

    2013-01-01

    The system for colorimetry adopted by the Commission Internationale de l'Eclairage (CIE) in 1931, along with its subsequent improvements, represents a family of light mixture models that has served well for many decades for stimulus specification and reproduction when highly controlled color standards are important. Still, with regard to color appearance many perceptual and cognitive factors are known to contribute to color similarity, and, in general, to all cognitive judgments of color. Using experimentally obtained odd-one-out triad similarity judgments from 52 observers, we demonstrate that CIE-based models can explain a good portion (but not all) of the color similarity data. Color difference quantified by CIELAB ΔE explained behavior at levels of 81% (across all colors), 79% (across red colors), and 66% (across blue colors). We show that the unexplained variation cannot be ascribed to inter- or intra-individual variations among the observers, and points to the presence of additional factors shared by the majority of responders. Based on this, we create a quantitative model of a lexicographic semiorder type, which shows how different perceptual and cognitive influences can trade-off when making color similarity judgments. We show that by incorporating additional influences related to categorical and lightness and saturation factors, the model explains more of the triad similarity behavior, namely, 91% (all colors), 90% (reds), and 87% (blues). We conclude that distance in a CIE model is but the first of several layers in a hierarchy of higher-order cognitive influences that shape color triad choices. We further discuss additional mitigating influences outside the scope of CIE modeling, which can be incorporated in this framework, including well-known influences from language, stimulus set effects, and color preference bias. We also discuss universal and cultural aspects of the model as well as non-uniformity of the color space with respect to different

  9. Isolation and quantitation of topoisomerase complexes accumulated on Escherichia coli chromosomal DNA.

    Science.gov (United States)

    Aedo, Sandra; Tse-Dinh, Yuk-Ching

    2012-11-01

    DNA topoisomerases are important targets in anticancer and antibacterial therapy because drugs can initiate cell death by stabilizing the transient covalent topoisomerase-DNA complex. In this study, we employed a method that uses CsCl density gradient centrifugation to separate unbound from DNA-bound GyrA/ParC in Escherichia coli cell lysates after quinolone treatment, allowing antibody detection and quantitation of the covalent complexes on slot blots. Using these procedures modified from the in vivo complexes of enzyme (ICE) bioassay, we found a correlation between gyrase-DNA complex formation and DNA replication inhibition at bacteriostatic (1× MIC) norfloxacin concentrations. Quantitation of the number of gyrase-DNA complexes per E. coli cell permitted an association between cell death and chromosomal gyrase-DNA complex accumulation at norfloxacin concentrations greater than 1× MIC. When comparing levels of gyrase-DNA complexes to topoisomerase IV-DNA complexes in the absence of drug, we observed that the gyrase-DNA complex level was higher (∼150-fold) than that of the topoisomerase IV-DNA complex. In addition, levels of gyrase and topoisomerase IV complexes reached a significant increase after 30 min of treatment at 1× and 1.7× MIC, respectively. These results are in agreement with gyrase being the primary target for quinolones in E. coli. We further validated the utility of this method for the study of topoisomerase-drug interactions in bacteria by showing the gyrase covalent complex reversibility after removal of the drug from the medium, and the resistant effect of the Ser83Leu gyrA mutation on accumulation of gyrase covalent complexes on chromosomal DNA.

  10. Identifying contributors of DNA mixtures by means of quantitative information of STR typing

    DEFF Research Database (Denmark)

    Tvedebrink, Torben; Eriksen, Poul Svante; Mogensen, Helle Smidt

    2012-01-01

    identified using polymorphic genetic markers. However, modern typing techniques supply additional quantitative data, which contain very important information about the observed evidence. This is particularly true for cases of DNA mixtures, where more than one individual has contributed to the observed...... biological stain. This article presents a method for including the quantitative information of short tandem repeat (STR) DNA mixtures in the LR. Also, an efficient algorithmic method for finding the best matching combination of DNA mixture profiles is derived and implemented in an on-line tool for two......- and three-person DNA mixtures. Finally, we demonstrate for two-person mixtures how this best matching pair of profiles can be used in estimating the likelihood ratio using importance sampling. The reason for using importance sampling for estimating the likelihood ratio is the often vast number...

  11. Quantitative analysis of DNA levels in maternal plasma in normal and Down syndrome pregnancies

    OpenAIRE

    Stejskal David; Doucha Jindrich; Kofer Josef; Nekolarova Katerina; Calda Pavel; Voslarova Sona; Hridelova Dana; Houbova Bela; Hromadnikova Ilona; Cinek Ondrej; Vavrirec Jan

    2002-01-01

    Abstract Background We investigated fetal and total DNA levels in maternal plasma in patients bearing fetuses affected with Down syndrome in comparison to controls carrying fetuses with normal karyotype. Methods DNA levels in maternal plasma were measured using real-time quantitative PCR using SRY and β-globin genes as markers. Twenty-one pregnant women with a singleton fetus at a gestational age ranging from 15 to 19 weeks recruited before amniocentesis (carried out for reasons including mat...

  12. Mineralization of human premolar occlusal fissures: a quantitative histochemical microanalysis

    OpenAIRE

    Campos, Antonio; Rodriguez, I. A.; Sanchez-Quevedo, M.C.; García, J. M.; Nieto-Albano, O.H.; Gómez de Ferraris, M.E.

    2000-01-01

    The mechanisms of cariogenesis in occlusal fissures remain elusive because of limited information about fissure structure and wall mineralization. The purpose of the present study was to determine the correlation between morphological patterns in occlusal fissures in human premolars and quantitative histochemical patterns of mineralization in the walls of these formations. We used scanning electron microscopy and quantitative X-ray microanalysis with the peak-t...

  13. Development and qualification of a high sensitivity, high throughput Q-PCR assay for quantitation of residual host cell DNA in purification process intermediate and drug substance samples.

    Science.gov (United States)

    Zhang, Wei; Wu, Meng; Menesale, Emily; Lu, Tongjun; Magliola, Aeona; Bergelson, Svetlana

    2014-11-01

    Methods of high sensitivity, accuracy and throughput are needed for quantitation of low level residual host cell DNA in purification process intermediates and drug substances of therapeutic proteins. In this study, we designed primer/probe sets targeting repetitive Alu repeats or Alu-equivalent sequences in the human, Chinese hamster and murine genomes. When used in quantitative polymerase chain reactions (Q-PCRs), these primer/probe sets showed high species specificity and gave significantly higher sensitivity compared to those targeting the low copy number GAPDH gene. This allowed for detection of residual host cell DNA of much lower concentrations and, for some samples, eliminated the need for DNA extraction. By combining the high sensitivity Alu Q-PCR with high throughput automated DNA extraction using an automated MagMAX magnetic particle processor, we successfully developed and qualified a highly accurate, specific, sensitive and efficient method for the quantitation of residual host cell DNA in process intermediates and drug substances of multiple therapeutic proteins purified from cells of multiple species. Compared to the previous method using manual DNA extraction and primer/probe sets targeting the GAPDH gene, this new method increased our DNA extraction throughput by over sevenfold, and lowered the lower limit of quantitation by up to eightfold. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Identification of Streptococcus parasanguinis DNA contamination in human buccal DNA samples

    OpenAIRE

    Mahfuz, Istiak; Cheng, Wei; White, Stefan J

    2013-01-01

    Background The use of buccal swabs in clinical and scientific studies is a very popular method of collecting DNA, due to its non-invasive nature of collection. However, contamination of the DNA sample may interfere with analysis. Findings Here we report the finding of Streptococcus parasanguinis bacterial DNA contamination in human buccal DNA samples, which led to preferential amplification of bacterial sequence with PCR primers designed against human sequence. Conclusion Contamination of buc...

  15. Qualitative and Quantitative Analyses of Glycogen in Human Milk.

    Science.gov (United States)

    Matsui-Yatsuhashi, Hiroko; Furuyashiki, Takashi; Takata, Hiroki; Ishida, Miyuki; Takumi, Hiroko; Kakutani, Ryo; Kamasaka, Hiroshi; Nagao, Saeko; Hirose, Junko; Kuriki, Takashi

    2017-02-22

    Identification as well as a detailed analysis of glycogen in human milk has not been shown yet. The present study confirmed that glycogen is contained in human milk by qualitative and quantitative analyses. High-performance anion exchange chromatography (HPAEC) and high-performance size exclusion chromatography with a multiangle laser light scattering detector (HPSEC-MALLS) were used for qualitative analysis of glycogen in human milk. Quantitative analysis was carried out by using samples obtained from the individual milks. The result revealed that the concentration of human milk glycogen varied depending on the mother's condition-such as the period postpartum and inflammation. The amounts of glycogen in human milk collected at 0 and 1-2 months postpartum were higher than in milk collected at 3-14 months postpartum. In the milk from mothers with severe mastitis, the concentration of glycogen was about 40 times higher than that in normal milk.

  16. Digital PCR Quantitation of Muscle Mitochondrial DNA: Age, Fiber Type, and Mutation-Induced Changes.

    Science.gov (United States)

    Herbst, Allen; Widjaja, Kevin; Nguy, Beatrice; Lushaj, Entela B; Moore, Timothy M; Hevener, Andrea L; McKenzie, Debbie; Aiken, Judd M; Wanagat, Jonathan

    2017-10-01

    Definitive quantitation of mitochondrial DNA (mtDNA) and mtDNA deletion mutation abundances would help clarify the role of mtDNA instability in aging. To more accurately quantify mtDNA, we applied the emerging technique of digital polymerase chain reaction to individual muscle fibers and muscle homogenates from aged rodents. Individual fiber mtDNA content correlated with fiber type and decreased with age. We adapted a digital polymerase chain reaction deletion assay that was accurate in mixing experiments to a mutation frequency of 0.03% and quantitated an age-induced increase in deletion frequency from rat muscle homogenates. Importantly, the deletion frequency measured in muscle homogenates strongly correlated with electron transport chain-deficient fiber abundance determined by histochemical analyses. These data clarify the temporal accumulation of mtDNA deletions that lead to electron chain-deficient fibers, a process culminating in muscle fiber loss. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Accurate quantitation of circulating cell-free mitochondrial DNA in plasma by droplet digital PCR.

    Science.gov (United States)

    Ye, Wei; Tang, Xiaojun; Liu, Chu; Wen, Chaowei; Li, Wei; Lyu, Jianxin

    2017-04-01

    To establish a method for accurate quantitation of circulating cell-free mitochondrial DNA (ccf-mtDNA) in plasma by droplet digital PCR (ddPCR), we designed a ddPCR method to determine the copy number of ccf-mtDNA by amplifying mitochondrial ND1 (MT-ND1). To evaluate the sensitivity and specificity of the method, a recombinant pMD18-T plasmid containing MT-ND1 sequences and mtDNA-deleted (ρ 0 ) HeLa cells were used, respectively. Subsequently, different plasma samples were prepared for ddPCR to evaluate the feasibility of detecting plasma ccf-mtDNA. In the results, the ddPCR method showed high sensitivity and specificity. When the DNA was extracted from plasma prior to ddPCR, the ccf-mtDNA copy number was higher than that measured without extraction. This difference was not due to a PCR inhibitor, such as EDTA-Na 2 , an anti-coagulant in plasma, because standard EDTA-Na 2 concentration (5 mM) did not significantly inhibit ddPCR reactions. The difference might be attributable to plasma exosomal mtDNA, which was 4.21 ± 0.38 copies/μL of plasma, accounting for ∼19% of plasma ccf-mtDNA. Therefore, ddPCR can quickly and reliably detect ccf-mtDNA from plasma with a prior DNA extraction step, providing for a more accurate detection of ccf-mtDNA. The direct use of plasma as a template in ddPCR is suitable for the detection of exogenous cell-free nucleic acids within plasma, but not of nucleic acids that have a vesicle-associated form, such as exosomal mtDNA. Graphical Abstract Designs of the present work. *: Module 1, #: Module 2, &: Module 3.

  18. Vitreous humour as a potential DNA source for postmortem human identification.

    Directory of Open Access Journals (Sweden)

    Renata Zbiec

    2007-06-01

    Full Text Available PURPOSE
    The aim of this study was the assessment of vitreous humor as a potential DNA for forensic human postmortem identification.

    MATERIAL AND METHODS
    Vitreous humor samples were collected using two alternative approaches from 25 corpses of either sex during autopsies. DNA was extracted by standard organic method. Recovered DNA was quantitiated fluorometrically. AmpFlSTR SGM Plus kit and ABI 310 Genetic Analyzer (Applera were used to obtain genetic profiles.

    RESULTS
    Different DNA yields were quantitated in vitreous body depending on cause of death and sampling approach.

    CONCLUSION
    Vitreous humor is a potential DNA for forensic human postmortem identification depending on a sampling method used.

  19. Rapid DNA extraction for specific detection and quantitation of Mycobacterium tuberculosis DNA in sputum specimens using taqman assays

    Science.gov (United States)

    Gomez, Diana I.; Mullin, Caroline S.; Mora-Guzmán, Francisco; Crespo-Solis, J. Gonzalo; Fisher-Hoch, Susan P.; McCormick, Joseph B.; Restrepo, Blanca I.

    2011-01-01

    SUMMARY Rapid tuberculosis (TB) detection is critical for disease control, and further quantitation of Mycobacterium tuberculosis (Mtb) in sputum is valuable for epidemiological and clinical studies. We evaluated a simple, robust and cost-efficient in-house DNA extraction and downstream taqman approach for detection and quantitation of Mtb genomes from sputum of newly-diagnosed TB patients and non-TB controls. DNA was extracted using guanidine isothiocyanate and silica-based spin columns in less than 2h, stored frozen, and taqman assays were used to detect Mtb with IS6110 and quantify it targeting RD1 and IS1081. The taqmans had a sensitivity > 95% in 108 culture-confirmed TB patients and specificity of 100% in 43 non-TB controls. Genome counts were correlated with the Mycobacterial Growth Indicator Tubes’ (MGIT) time-to-detection values (1/TTD×1000; rho=0.66; p<0.001) in 91 TB patients (33 excluded with MGIT contamination). This linear relationship was nearly identical between mycobacteria isolated from sputum and H37Rv Mtb grown in-vitro to its log phase. TB treatment between 3 and 7 days was associated with lower 1/TTD×1000 values but not with genome counts. Together, our protocol provides rapid, specific, inexpensive and quantitative detection of Mtb DNA in fresh or stored sputa making it a robust tool for prompt TB diagnosis, and with potential use for clinical and epidemiologic studies. PMID:22088321

  20. DNA methylation analysis in human cancer

    OpenAIRE

    O'Sullivan, Eileen; Goggins, Michael

    2013-01-01

    The functional impact of aberrant DNA methylation and the widespread alterations in DNA methylation in cancer development has led to the development of a variety of methods to characterize the DNA methylation patterns. This chapter will critique and describe the major approaches to analyzing DNA methylation.

  1. A Multiplexed, Probe-Based Quantitative PCR Assay for DNA of Phytophthora sojae

    Science.gov (United States)

    Phytophthora sojae (Kaufm. & Gerd.) causes seed rot, pre- and post-emergence damping off, and sometimes foliar blight in soybean (Glycine max). Crop loss may approach 100% with susceptible cultivars. We report here the development of a unique quantitative PCR assay specific to DNA of P. sojae, and a...

  2. The persistence of human DNA in soil following surface decomposition.

    Science.gov (United States)

    Emmons, Alexandra L; DeBruyn, Jennifer M; Mundorff, Amy Z; Cobaugh, Kelly L; Cabana, Graciela S

    2017-09-01

    Though recent decades have seen a marked increase in research concerning the impact of human decomposition on the grave soil environment, the fate of human DNA in grave soil has been relatively understudied. With the purpose of supplementing the growing body of literature in forensic soil taphonomy, this study assessed the relative persistence of human DNA in soil over the course of decomposition. Endpoint PCR was used to assess the presence or absence of human nuclear and mitochondrial DNA, while qPCR was used to evaluate the quantity of human DNA recovered from the soil beneath four cadavers at the University of Tennessee's Anthropology Research Facility (ARF). Human nuclear DNA from the soil was largely unrecoverable, while human mitochondrial DNA was detectable in the soil throughout all decomposition stages. Mitochondrial DNA copy abundances were not significantly different between decomposition stages and were not significantly correlated to soil edaphic parameters tested. There was, however, a significant positive correlation between mitochondrial DNA copy abundances and the human associated bacteria, Bacteroides, as estimated by 16S rRNA gene abundances. These results show that human mitochondrial DNA can persist in grave soil and be consistently detected throughout decomposition. Copyright © 2017 The Chartered Society of Forensic Sciences. Published by Elsevier B.V. All rights reserved.

  3. Quantitation of glial fibrillary acidic protein in human brain tumours

    DEFF Research Database (Denmark)

    Rasmussen, S; Bock, E; Warecka, K

    1980-01-01

    The glial fibrillary acidic protein (GFA) content of 58 human brain tumours was determined by quantitative immunoelectrophoresis, using monospecific antibody against GFA. Astrocytomas, glioblastomas, oligodendrogliomas, spongioblastomas, ependymomas and medulloblastomas contained relatively high...... amounts of GFA, up to 85 times the concentration in parietal grey substance of normal human brain. GFA was not found in neurinomas, meningiomas, adenomas of the hypophysis, or in a single case of metastasis of adenocarcinoma. Non-glial tumours of craniopharyngioma and haemangioblastoma were infiltrated...

  4. Freezing fecal samples prior to DNA extraction affects the Firmicutes to Bacteroidetes ratio determined by downstream quantitative PCR analysis.

    Science.gov (United States)

    Bahl, Martin Iain; Bergström, Anders; Licht, Tine Rask

    2012-04-01

    Freezing stool samples prior to DNA extraction and downstream analysis is widely used in metagenomic studies of the human microbiota but may affect the inferred community composition. In this study, DNA was extracted either directly or following freeze storage of three homogenized human fecal samples using three different extraction methods. No consistent differences were observed in DNA yields between extractions on fresh and frozen samples; however, differences were observed between extraction methods. Quantitative PCR analysis was subsequently performed on all DNA samples using six different primer pairs targeting 16S rRNA genes of significant bacterial groups, and the community composition was evaluated by comparing specific ratios of the calculated abundances. In seven of nine cases, the Firmicutes to Bacteroidetes 16S rRNA gene ratio was significantly higher in fecal samples that had been frozen compared to identical samples that had not. This effect was further supported by qPCR analysis of bacterial groups within these two phyla. The results demonstrate that storage conditions of fecal samples may adversely affect the determined Firmicutes to Bacteroidetes ratio, which is a frequently used biomarker in gut microbiology. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  5. Human Parvovirus B19 Utilizes Cellular DNA Replication Machinery for Viral DNA Replication.

    Science.gov (United States)

    Zou, Wei; Wang, Zekun; Xiong, Min; Chen, Aaron Yun; Xu, Peng; Ganaie, Safder S; Badawi, Yomna; Kleiboeker, Steve; Nishimune, Hiroshi; Ye, Shui Qing; Qiu, Jianming

    2017-12-13

    Human parvovirus B19 (B19V) infection of human erythroid progenitor cells (EPCs) induces a DNA damage response and cell cycle arrest at late S phase, which facilitates viral DNA replication. However, it is not clear exactly which cellular factors are employed by this single-stranded DNA virus. Here, we used microarrays to systematically analyze the dynamic transcriptome of EPCs infected with B19V. We found that DNA metabolism, DNA replication, DNA repair, DNA damage response, cell cycle, and cell cycle arrest pathways were significantly regulated after B19V infection. Confocal microscopy analyses revealed that most cellular DNA replication proteins were recruited to the centers of viral DNA replication, but not the DNA repair DNA polymerases. Our results suggest that DNA replication polymerase δ and polymerase α are responsible for B19V DNA replication by knocking down its expression in EPCs. We further showed that although RPA32 is essential for B19V DNA replication and the phosphorylated forms of RPA32 colocalized with the replicating viral genomes, RPA32 phosphorylation was not necessary for B19V DNA replication. Thus, this study provides evidence that B19V uses the cellular DNA replication machinery for viral DNA replication.IMPORTANCE Human parvovirus B19 (B19V) infection can cause transient aplastic crisis, persistent viremia, and pure red-cell aplasia. In fetuses, B19V infection can result in non-immune hydrops fetalis and fetal death. These clinical manifestations of B19V infection are a direct outcome of the death of human erythroid progenitors that host B19V replication. B19V infection induces a DNA damage response that is important for cell cycle arrest at late S phase. Here, we analyzed dynamic changes in cellular gene expression, and found that DNA metabolic processes are tightly regulated during B19V infection. Although genes involved in cellular DNA replication were downregulated overall, the cellular DNA replication machinery was tightly

  6. Human identification & forensic analyses of degraded or low level DNA

    NARCIS (Netherlands)

    Westen, Antoinette-Andrea

    2013-01-01

    DNA-based human identification is employed in varying situations, such as disaster victim identification, relationship testing and forensic analyses. When DNA is of low quality and/or quantity, standard methods for DNA profiling may not suffice. The research described in this thesis is aimed at the

  7. Triplet repeat DNA structures and human genetic disease: dynamic ...

    Indian Academy of Sciences (India)

    Triplet repeat DNA structures and human genetic disease: dynamic mutations from dynamic DNA. Richard R Sinden Vladimir N ... Different models have been proposed for the expansion of triplet repeats, most of which presume the formation of alternative DNA structures in repeat tracts. One of the most likely structures, ...

  8. Tenacity of Exogenous Human Papillomavirus DNA in Sperm Washing

    OpenAIRE

    Brossfield, Jeralyn E.; Philip J. Chan; Patton, William C.; King, Alan

    1999-01-01

    Purpose:Sperm cells have been shown to take up exogenous DNA readily. The hypothesis was that sperm washing would remove exogenous viral DNA infecting sperm cells. The objective was to compare three types of sperm washing procedures for their capacity to remove exogenous human papillomavirus (HPV) DNA from infected sperm.

  9. Quantitative PCR analysis of diepoxybutane and epihalohydrin damage to nuclear versus mitochondrial DNA

    Energy Technology Data Exchange (ETDEWEB)

    LaRiviere, Frederick J. [Department of Chemistry, Washington and Lee University, Lexington, VA 24450 (United States); Newman, Adam G.; Watts, Megan L.; Bradley, Sharonda Q.; Juskewitch, Justin E. [Department of Chemistry, Colby College, 5757 Mayflower Hill Drive, Waterville, ME 04901 (United States); Greenwood, Paul G. [Department of Biology, Colby College, Waterville, ME 04901 (United States); Millard, Julie T., E-mail: jtmillar@colby.edu [Department of Chemistry, Colby College, 5757 Mayflower Hill Drive, Waterville, ME 04901 (United States)

    2009-05-12

    The bifunctional alkylating agents diepoxybutane (DEB) and epichlorohydrin (ECH) are linked to the elevated incidence of certain cancers among workers in the synthetic polymer industry. Both compounds form interstrand cross-links within duplex DNA, an activity suggested to contribute to their cytotoxicity. To assess the DNA targeting of these compounds in vivo, we assayed for damage within chicken erythro-progenitor cells at three different sites: one within mitochondrial DNA, one within expressed nuclear DNA, and one within unexpressed nuclear DNA. We determined the degree of damage at each site via a quantitative polymerase chain reaction, which compares amplification of control, untreated DNA to that from cells exposed to the agent in question. We found that ECH and the related compound epibromohydrin preferentially target nuclear DNA relative to mitochondrial DNA, whereas DEB reacts similarly with the two genomes. Decreased reactivity of the mitochondrial genome could contribute to the reduced apoptotic potential of ECH relative to DEB. Additionally, formation of lesions by all agents occurred at comparable levels for unexpressed and expressed nuclear loci, suggesting that alkylation is unaffected by the degree of chromatin condensation.

  10. INSPIIRED: A Pipeline for Quantitative Analysis of Sites of New DNA Integration in Cellular Genomes

    Directory of Open Access Journals (Sweden)

    Eric Sherman

    2017-03-01

    Full Text Available Integration of new DNA into cellular genomes mediates replication of retroviruses and transposons; integration reactions have also been adapted for use in human gene therapy. Tracking the distributions of integration sites is important to characterize populations of transduced cells and to monitor potential outgrow of pathogenic cell clones. Here, we describe a pipeline for quantitative analysis of integration site distributions named INSPIIRED (integration site pipeline for paired-end reads. We describe optimized biochemical steps for site isolation using Illumina paired-end sequencing, including new technology for suppressing recovery of unwanted contaminants, then software for alignment, quality control, and management of integration site sequences. During library preparation, DNAs are broken by sonication, so that after ligation-mediated PCR the number of ligation junction sites can be used to infer abundance of gene-modified cells. We generated integration sites of known positions in silico, and we describe optimization of sample processing parameters refined by comparison to truth. We also present a novel graph-theory-based method for quantifying integration sites in repeated sequences, and we characterize the consequences using synthetic and experimental data. In an accompanying paper, we describe an additional set of statistical tools for data analysis and visualization. Software is available at https://github.com/BushmanLab/INSPIIRED.

  11. Quantitation of glucocorticoid receptor DNA-binding dynamics by single-molecule microscopy and FRAP.

    Science.gov (United States)

    Groeneweg, Femke L; van Royen, Martin E; Fenz, Susanne; Keizer, Veer I P; Geverts, Bart; Prins, Jurrien; de Kloet, E Ron; Houtsmuller, Adriaan B; Schmidt, Thomas S; Schaaf, Marcel J M

    2014-01-01

    Recent advances in live cell imaging have provided a wealth of data on the dynamics of transcription factors. However, a consistent quantitative description of these dynamics, explaining how transcription factors find their target sequences in the vast amount of DNA inside the nucleus, is still lacking. In the present study, we have combined two quantitative imaging methods, single-molecule microscopy and fluorescence recovery after photobleaching, to determine the mobility pattern of the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR), two ligand-activated transcription factors. For dexamethasone-activated GR, both techniques showed that approximately half of the population is freely diffusing, while the remaining population is bound to DNA. Of this DNA-bound population about half the GRs appeared to be bound for short periods of time (∼ 0.7 s) and the other half for longer time periods (∼ 2.3 s). A similar pattern of mobility was seen for the MR activated by aldosterone. Inactive receptors (mutant or antagonist-bound receptors) show a decreased DNA binding frequency and duration, but also a higher mobility for the diffusing population. Likely, very brief (≤ 1 ms) interactions with DNA induced by the agonists underlie this difference in diffusion behavior. Surprisingly, different agonists also induce different mobilities of both receptors, presumably due to differences in ligand-induced conformational changes and receptor complex formation. In summary, our data provide a consistent quantitative model of the dynamics of GR and MR, indicating three types of interactions with DNA, which fit into a model in which frequent low-affinity DNA binding facilitates the search for high-affinity target sequences.

  12. Quantitation of glucocorticoid receptor DNA-binding dynamics by single-molecule microscopy and FRAP.

    Directory of Open Access Journals (Sweden)

    Femke L Groeneweg

    Full Text Available Recent advances in live cell imaging have provided a wealth of data on the dynamics of transcription factors. However, a consistent quantitative description of these dynamics, explaining how transcription factors find their target sequences in the vast amount of DNA inside the nucleus, is still lacking. In the present study, we have combined two quantitative imaging methods, single-molecule microscopy and fluorescence recovery after photobleaching, to determine the mobility pattern of the glucocorticoid receptor (GR and the mineralocorticoid receptor (MR, two ligand-activated transcription factors. For dexamethasone-activated GR, both techniques showed that approximately half of the population is freely diffusing, while the remaining population is bound to DNA. Of this DNA-bound population about half the GRs appeared to be bound for short periods of time (∼ 0.7 s and the other half for longer time periods (∼ 2.3 s. A similar pattern of mobility was seen for the MR activated by aldosterone. Inactive receptors (mutant or antagonist-bound receptors show a decreased DNA binding frequency and duration, but also a higher mobility for the diffusing population. Likely, very brief (≤ 1 ms interactions with DNA induced by the agonists underlie this difference in diffusion behavior. Surprisingly, different agonists also induce different mobilities of both receptors, presumably due to differences in ligand-induced conformational changes and receptor complex formation. In summary, our data provide a consistent quantitative model of the dynamics of GR and MR, indicating three types of interactions with DNA, which fit into a model in which frequent low-affinity DNA binding facilitates the search for high-affinity target sequences.

  13. Structural basis of human PCNA sliding on DNA

    Science.gov (United States)

    de March, Matteo; Merino, Nekane; Barrera-Vilarmau, Susana; Crehuet, Ramon; Onesti, Silvia; Blanco, Francisco J.; de Biasio, Alfredo

    2017-01-01

    Sliding clamps encircle DNA and tether polymerases and other factors to the genomic template. However, the molecular mechanism of clamp sliding on DNA is unknown. Using crystallography, NMR and molecular dynamics simulations, here we show that the human clamp PCNA recognizes DNA through a double patch of basic residues within the ring channel, arranged in a right-hand spiral that matches the pitch of B-DNA. We propose that PCNA slides by tracking the DNA backbone via a `cogwheel' mechanism based on short-lived polar interactions, which keep the orientation of the clamp invariant relative to DNA. Mutation of residues at the PCNA-DNA interface has been shown to impair the initiation of DNA synthesis by polymerase δ (pol δ). Therefore, our findings suggest that a clamp correctly oriented on DNA is necessary for the assembly of a replication-competent PCNA-pol δ holoenzyme.

  14. Persistent organic pollutants alter DNA methylation during human adipocyte differentiation

    NARCIS (Netherlands)

    Dungen, van den Myrthe; Murk, Tinka; Steegenga, Wilma; Gils-Kok, van Dieuwertje

    2016-01-01

    Genome-wide DNA methylation profiling was performed in human mesenchymal stem cells (hMSCs) differentiated into adipocytes (day 10) while being continuously exposed to either one of three different persistent organic pollutants (POPs), namely TCDD, PFOS, and TBT. The Illumina Infinium 450K Human DNA

  15. Quantitative Trait Locus Mapping in Dairy Cattle by Means of Selective Milk DNA Pooling Using Dinucleotide Microsatellite Markers: Analysis of Milk Protein Percentage

    National Research Council Canada - National Science Library

    Lipkin, Ehud; Mosig, Mathias O; Darvasi, Ariel; Ezra, Ephraim; Shalom, A; Friedmann, Adam; Soller, Morris

    1998-01-01

    "Selective DNA pooling" accomplishes quantitative trait locus (QTL) mapping through densitometric estimates of marker allele frequencies in pooled DNA samples of phenotypically extreme individuals. With poly(TG...

  16. Oxidized Extracellular DNA as a Stress Signal in Human Cells

    Directory of Open Access Journals (Sweden)

    Aleksei V. Ermakov

    2013-01-01

    Full Text Available The term “cell-free DNA” (cfDNA was recently coined for DNA fragments from plasma/serum, while DNA present in in vitro cell culture media is known as extracellular DNA (ecDNA. Under oxidative stress conditions, the levels of oxidative modification of cellular DNA and the rate of cell death increase. Dying cells release their damaged DNA, thus, contributing oxidized DNA fragments to the pool of cfDNA/ecDNA. Oxidized cell-free DNA could serve as a stress signal that promotes irradiation-induced bystander effect. Evidence points to TLR9 as a possible candidate for oxidized DNA sensor. An exposure to oxidized ecDNA stimulates a synthesis of reactive oxygen species (ROS that evokes an adaptive response that includes transposition of the homologous loci within the nucleus, polymerization and the formation of the stress fibers of the actin, as well as activation of the ribosomal gene expression, and nuclear translocation of NF-E2 related factor-2 (NRF2 that, in turn, mediates induction of phase II detoxifying and antioxidant enzymes. In conclusion, the oxidized DNA is a stress signal released in response to oxidative stress in the cultured cells and, possibly, in the human body; in particular, it might contribute to systemic abscopal effects of localized irradiation treatments.

  17. Progress towards in vitro quantitative imaging of human femur using compound quantitative ultrasonic tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lasaygues, Philippe [Laboratoire de Mecanique et d' Acoustique UPR CNRS 7051, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20 (France); Ouedraogo, Edgard [Laboratoire d' Imagerie Parametrique UMR CNRS 7623, 15, rue de l' Ecole de medecine, 75006 Paris (France); Lefebvre, Jean-Pierre [Laboratoire de Mecanique et d' Acoustique UPR CNRS 7051, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20 (France); Gindre, Marcel [Laboratoire d' Imagerie Parametrique UMR CNRS 7623, 15, rue de l' Ecole de medecine, 75006 Paris (France); Talmant, Marilyne [Laboratoire d' Imagerie Parametrique UMR CNRS 7623, 15, rue de l' Ecole de medecine, 75006 Paris (France); Laugier, Pascal [Laboratoire d' Imagerie Parametrique UMR CNRS 7623, 15, rue de l' Ecole de medecine, 75006 Paris (France)

    2005-06-07

    The objective of this study is to make cross-sectional ultrasonic quantitative tomography of the diaphysis of long bones. Ultrasonic propagation in bones is affected by the severe mismatch between the acoustic properties of this biological solid and those of the surrounding soft medium, namely, the soft tissues in vivo or water in vitro. Bone imaging is then a nonlinear inverse-scattering problem. In this paper, we showed that in vitro quantitative images of sound velocities in a human femur cross section could be reconstructed by combining ultrasonic reflection tomography (URT), which provides images of the macroscopic structure of the bone, and ultrasonic transmission tomography (UTT), which provides quantitative images of the sound velocity. For the shape, we developed an image-processing tool to extract the external and internal boundaries and cortical thickness measurements. For velocity mapping, we used a wavelet analysis tool adapted to ultrasound, which allowed us to detect precisely the time of flight from the transmitted signals. A brief review of the ultrasonic tomography that we developed using correction algorithms of the wavepaths and compensation procedures are presented. Also shown are the first results of our analyses on models and specimens of long bone using our new iterative quantitative protocol.

  18. Effects of DNA extraction and purification methods on real-time quantitative PCR analysis of Roundup Ready soybean.

    Science.gov (United States)

    Demeke, Tigst; Ratnayaka, Indira; Phan, Anh

    2009-01-01

    The quality of DNA affects the accuracy and repeatability of quantitative PCR results. Different DNA extraction and purification methods were compared for quantification of Roundup Ready (RR) soybean (event 40-3-2) by real-time PCR. DNA was extracted using cetylmethylammonium bromide (CTAB), DNeasy Plant Mini Kit, and Wizard Magnetic DNA purification system for food. CTAB-extracted DNA was also purified using the Zymo (DNA Clean & Concentrator 25 kit), Qtip 100 (Qiagen Genomic-Tip 100/G), and QIAEX II Gel Extraction Kit. The CTAB extraction method provided the largest amount of DNA, and the Zymo purification kit resulted in the highest percentage of DNA recovery. The Abs260/280 and Abs260/230 ratios were less than the expected values for some of the DNA extraction and purification methods used, indicating the presence of substances that could inhibit PCR reactions. Real-time quantitative PCR results were affected by the DNA extraction and purification methods used. Further purification or dilution of the CTAB DNA was required for successful quantification of RR soybean. Less variability of quantitative PCR results was observed among experiments and replications for DNA extracted and/or purified by CTAB, CTAB+Zymo, CTAB+Qtip 100, and DNeasy methods. Correct and repeatable results for real-time PCR quantification of RR soybean were achieved using CTAB DNA purified with Zymo and Qtip 100 methods.

  19. Quantitative DNase footprint titration: a tool for analyzing the energetics of protein-DNA interactions.

    Science.gov (United States)

    Connaghan-Jones, Keith D; Moody, Amie D; Bain, David L

    2008-01-01

    A major goal in biomedical research is to determine the mechanisms responsible for gene regulation. However, the promoters and operators that control transcription are often complex in nature, containing multiple-binding sites with which DNA-binding proteins can interact cooperatively. Quantitative DNase footprint titration is one of the few techniques capable of resolving the microscopic binding affinities responsible for the macroscopic assembly process. Here, we present a step-by-step protocol for carrying out a footprint titration experiment. We then describe how to quantify the resultant images to generate individual-site binding curves. Finally, we derive basic equations for binding at each site and present an overview of the fitting process, applying it to the anticipated results. Users should anticipate that the footprinting experiment will take 3-5 d starting from DNA template isolation to image acquisition and quantitation.

  20. An Improved DNA Extraction Method for Efficient and Quantitative Recovery of Phytoplankton Diversity in Natural Assemblages.

    Science.gov (United States)

    Yuan, Jian; Li, Meizhen; Lin, Senjie

    2015-01-01

    Marine phytoplankton are highly diverse with different species possessing different cell coverings, posing challenges for thoroughly breaking the cells in DNA extraction yet preserving DNA integrity. While quantitative molecular techniques have been increasingly used in phytoplankton research, an effective and simple method broadly applicable to different lineages and natural assemblages is still lacking. In this study, we developed a bead-beating protocol based on our previous experience and tested it against 9 species of phytoplankton representing different lineages and different cell covering rigidities. We found the bead-beating method enhanced the final yield of DNA (highest as 2 folds) in comparison with the non-bead-beating method, while also preserving the DNA integrity. When our method was applied to a field sample collected at a subtropical bay located in Xiamen, China, the resultant ITS clone library revealed a highly diverse assemblage of phytoplankton and other micro-eukaryotes, including Archaea, Amoebozoa, Chlorophyta, Ciliphora, Bacillariophyta, Dinophyta, Fungi, Metazoa, etc. The appearance of thecate dinoflagellates, thin-walled phytoplankton and "naked" unicellular organisms indicates that our method could obtain the intact DNA of organisms with different cell coverings. All the results demonstrate that our method is useful for DNA extraction of phytoplankton and environmental surveys of their diversity and abundance.

  1. An Improved DNA Extraction Method for Efficient and Quantitative Recovery of Phytoplankton Diversity in Natural Assemblages.

    Directory of Open Access Journals (Sweden)

    Jian Yuan

    Full Text Available Marine phytoplankton are highly diverse with different species possessing different cell coverings, posing challenges for thoroughly breaking the cells in DNA extraction yet preserving DNA integrity. While quantitative molecular techniques have been increasingly used in phytoplankton research, an effective and simple method broadly applicable to different lineages and natural assemblages is still lacking. In this study, we developed a bead-beating protocol based on our previous experience and tested it against 9 species of phytoplankton representing different lineages and different cell covering rigidities. We found the bead-beating method enhanced the final yield of DNA (highest as 2 folds in comparison with the non-bead-beating method, while also preserving the DNA integrity. When our method was applied to a field sample collected at a subtropical bay located in Xiamen, China, the resultant ITS clone library revealed a highly diverse assemblage of phytoplankton and other micro-eukaryotes, including Archaea, Amoebozoa, Chlorophyta, Ciliphora, Bacillariophyta, Dinophyta, Fungi, Metazoa, etc. The appearance of thecate dinoflagellates, thin-walled phytoplankton and "naked" unicellular organisms indicates that our method could obtain the intact DNA of organisms with different cell coverings. All the results demonstrate that our method is useful for DNA extraction of phytoplankton and environmental surveys of their diversity and abundance.

  2. A high-throughput and quantitative method to assess the mutagenic potential of translesion DNA synthesis

    Science.gov (United States)

    Taggart, David J.; Camerlengo, Terry L.; Harrison, Jason K.; Sherrer, Shanen M.; Kshetry, Ajay K.; Taylor, John-Stephen; Huang, Kun; Suo, Zucai

    2013-01-01

    Cellular genomes are constantly damaged by endogenous and exogenous agents that covalently and structurally modify DNA to produce DNA lesions. Although most lesions are mended by various DNA repair pathways in vivo, a significant number of damage sites persist during genomic replication. Our understanding of the mutagenic outcomes derived from these unrepaired DNA lesions has been hindered by the low throughput of existing sequencing methods. Therefore, we have developed a cost-effective high-throughput short oligonucleotide sequencing assay that uses next-generation DNA sequencing technology for the assessment of the mutagenic profiles of translesion DNA synthesis catalyzed by any error-prone DNA polymerase. The vast amount of sequencing data produced were aligned and quantified by using our novel software. As an example, the high-throughput short oligonucleotide sequencing assay was used to analyze the types and frequencies of mutations upstream, downstream and at a site-specifically placed cis–syn thymidine–thymidine dimer generated individually by three lesion-bypass human Y-family DNA polymerases. PMID:23470999

  3. Developmental validation of a real-time PCR assay for the simultaneous quantification of total human and male DNA.

    Science.gov (United States)

    Krenke, Benjamin E; Nassif, Nadine; Sprecher, Cynthia J; Knox, Curtis; Schwandt, Melissa; Storts, Douglas R

    2008-12-01

    Multiplex human short tandem repeat analysis demands reliable DNA quantification to consistently produce interpretable genotypes. The Plexor HY System is a multiplex quantitative PCR assay to quantify total human and male DNA. We performed developmental validation of the Plexor HY System to demonstrate the performance capabilities and limitations of the assay for forensic applications. Validation studies examined: (a) human specificity, (b) sensitivity, (c) quantification of degraded DNA, (d) impact of inhibitors, (e) male/female mixture and Y-assay male specificity, (f) reproducibility and concordance and (g) population studies.

  4. Human RAD52 Captures and Holds DNA Strands, Increases DNA Flexibility, and Prevents Melting of Duplex DNA: Implications for DNA Recombination

    Directory of Open Access Journals (Sweden)

    Ineke Brouwer

    2017-03-01

    Full Text Available Human RAD52 promotes annealing of complementary single-stranded DNA (ssDNA. In-depth knowledge of RAD52-DNA interaction is required to understand how its activity is integrated in DNA repair processes. Here, we visualize individual fluorescent RAD52 complexes interacting with single DNA molecules. The interaction with ssDNA is rapid, static, and tight, where ssDNA appears to wrap around RAD52 complexes that promote intra-molecular bridging. With double-stranded DNA (dsDNA, interaction is slower, weaker, and often diffusive. Interestingly, force spectroscopy experiments show that RAD52 alters the mechanics dsDNA by enhancing DNA flexibility and increasing DNA contour length, suggesting intercalation. RAD52 binding changes the nature of the overstretching transition of dsDNA and prevents DNA melting, which is advantageous for strand clamping during or after annealing. DNA-bound RAD52 is efficient at capturing ssDNA in trans. Together, these effects may help key steps in DNA repair, such as second-end capture during homologous recombination or strand annealing during RAD51-independent recombination reactions.

  5. Fecal collection, ambient preservation, and DNA extraction for PCR amplification of bacterial and human markers from human feces.

    Science.gov (United States)

    Nechvatal, Jordan M; Ram, Jeffrey L; Basson, Marc D; Namprachan, Phanramphoei; Niec, Stephanie R; Badsha, Kawsar Z; Matherly, Larry H; Majumdar, Adhip P N; Kato, Ikuko

    2008-02-01

    Feces contain intestinal bacteria and exfoliated epithelial cells that may provide useful information concerning gastrointestinal tract health. Intestinal bacteria that synthesize or metabolize potential carcinogens and produce anti-tumorigenic products may have relevance to colorectal cancer, the second most common cause of cancer deaths in the USA. To facilitate epidemiological studies relating bacterial and epithelial cell DNA and RNA markers, preservative/extraction methods suitable for self-collection and shipping of fecal samples at room temperature were tested. Purification and PCR amplification of fecal DNA were compared after preservation of stool samples in RNAlater (R) or Paxgene (P), or after drying over silica gel (S) or on Whatman FTA cards (W). Comparisons were made to samples frozen in liquid nitrogen (N2). DNA purification methods included Whatman (accompanying FTA cards), Mo-Bio Fecal (MB), Qiagen Stool (QS), and others. Extraction methods were compared for amount of DNA extracted, DNA amplifiable in a real-time SYBR-Green quantitative PCR format, and the presence of PCR inhibitors. DNA can be extracted after room temperature storage for five days from W, R, S and P, and from N2 frozen samples. High amounts of total DNA and PCR-amplifiable Bacteroides spp. DNA (34%+/-9% of total DNA) with relatively little PCR inhibition were especially obtained with QS extraction applied to R preserved samples (method QS-R). DNA for human reduced folate carrier (SLC19A1) genomic sequence was also detected in 90% of the QS-R extracts. Thus, fecal DNA is well preserved by methods suitable for self-collection that may be useful in future molecular epidemiological studies of intestinal bacteria and human cancer markers.

  6. Specific and sensitive quantitative RT-PCR of miRNAs with DNA primers

    DEFF Research Database (Denmark)

    Balcells, Ingrid; Cirera, Susanna; Busk, Peter Kamp

    2011-01-01

    Background MicroRNAs are important regulators of gene expression at the post-transcriptional level and play an important role in many biological processes. Due to the important biological role it is of great interest to quantitatively determine their expression level in different biological...... settings. Results We describe a PCR method for quantification of microRNAs based on a single reverse transcription reaction for all microRNAs combined with real-time PCR with two, microRNA-specific DNA primers. Primer annealing temperatures were optimized by adding a DNA tail to the primers and could...... be designed with a success rate of 94%. The method was able to quantify synthetic templates over eight orders of magnitude and readily discriminated between microRNAs with single nucleotide differences. Importantly, PCR with DNA primers yielded significantly higher amplification efficiencies of biological...

  7. Forensic aspects of mass disasters: strategic considerations for DNA-based human identification.

    Science.gov (United States)

    Budowle, Bruce; Bieber, Frederick R; Eisenberg, Arthur J

    2005-07-01

    Many mass disasters result in loss of lives. Law enforcement and/or public safety and health officials often have the responsibility for identifying the human remains found at the scene, so they can be returned to their families. The recovered human remains range from being relatively intact to highly degraded. DNA-based identity testing is a powerful tool for victim identification in that the data are not restricted to any particular one to one body landmark comparison and DNA profile comparisons can be used to associate separated remains or body parts. Even though DNA typing is straightforward, a disaster is a chaotic environment that can complicate effective identification of the remains. With some planning, or at least identification of the salient features to consider, stress can be reduced for those involved in the identification process. General guidelines are provided for developing an action plan for identification of human remains from a mass disaster by DNA analysis. These include: (1) sample collection, preservation, shipping and storage; (2) tracking and chain of custody issues; (3) laboratory facilities; (4) quality assurance and quality control practices; (5) parsing out work; (6) extraction and typing; (7) interpretation of results; (8) automation; (9) software for tracking and managing data; (10) the use of an advisory panel; (11) education and communication; and (12) privacy issues. In addition, key technologies that may facilitate the identification process are discussed, such as resin based DNA extraction, real-time PCR for quantitation of DNA, use of mini-STRs, SNP detection procedures, and software. Many of the features necessary for DNA typing of human remains from a mass disaster are the same as those for missing persons' cases. Therefore, developing a missing persons DNA identification program would also provide the basis for a mass disaster human remains DNA identification program.

  8. Mechanism of Error-Free DNA Replication Past Lucidin-Derived DNA Damage by Human DNA Polymerase κ.

    Science.gov (United States)

    Yockey, Oliver P; Jha, Vikash; Ghodke, Pratibha P; Xu, Tianzuo; Xu, Wenyan; Ling, Hong; Pradeepkumar, P I; Zhao, Linlin

    2017-11-20

    DNA damage impinges on genetic information flow and has significant implications in human disease and aging. Lucidin-3-O-primeveroside (LuP) is an anthraquinone derivative present in madder root, which has been used as a coloring agent and food additive. LuP can be metabolically converted to genotoxic compound lucidin, which subsequently forms lucidin-specific N2-2'-deoxyguanosine (N2-dG) and N6-2'-deoxyadenosine (N6-dA) DNA adducts. Lucidin is mutagenic and carcinogenic in rodents but has low carcinogenic risks in humans. To understand the molecular mechanism of low carcinogenicity of lucidin in humans, we performed DNA replication assays using site-specifically modified oligodeoxynucleotides containing a structural analogue (LdG) of lucidin-N2-dG DNA adduct and determined the crystal structures of DNA polymerase (pol) κ in complex with LdG-bearing DNA and an incoming nucleotide. We examined four human pols (pol η, pol ι, pol κ, and Rev1) in their efficiency and accuracy during DNA replication with LdG; these pols are key players in translesion DNA synthesis. Our results demonstrate that pol κ efficiently and accurately replicates past the LdG adduct, whereas DNA replication by pol η, pol ι is compromised to different extents. Rev1 retains its ability to incorporate dCTP opposite the lesion albeit with decreased efficiency. Two ternary crystal structures of pol κ illustrate that the LdG adduct is accommodated by pol κ at the enzyme active site during insertion and postlesion-extension steps. The unique open active site of pol κ allows the adducted DNA to adopt a standard B-form for accurate DNA replication. Collectively, these biochemical and structural data provide mechanistic insights into the low carcinogenic risk of lucidin in humans.

  9. Sperm DNA fragmentation affects epigenetic feature in human male pronucleus.

    Science.gov (United States)

    Rajabi, H; Mohseni-Kouchesfehani, H; Eslami-Arshaghi, T; Salehi, M

    2018-02-01

    To evaluate whether the sperm DNA fragmentation affects male pronucleus epigenetic factors, semen analysis was performed and DNA fragmentation was assessed by the method of sperm chromatin structure assay (SCSA). Human-mouse interspecies fertilisation was used to create human male pronucleus. Male pronucleus DNA methylation and H4K12 acetylation were evaluated by immunostaining. Results showed a significant positive correlation between the level of sperm DNA fragmentation and DNA methylation in male pronuclei. In other words, an increase in DNA damage caused an upsurge in DNA methylation. In the case of H4K12 acetylation, no correlation was detected between DNA damage and the level of histone acetylation in the normal group, but results for the group in which male pronuclei were derived from sperm cells with DNA fragmentation, increased DNA damage led to a decreased acetylation level. Sperm DNA fragmentation interferes with the active demethylation process and disrupts the insertion of histones into the male chromatin in the male pronucleus, following fertilisation. © 2017 Blackwell Verlag GmbH.

  10. Quantitative analysis of DNA levels in maternal plasma in normal and Down syndrome pregnancies

    Directory of Open Access Journals (Sweden)

    Stejskal David

    2002-05-01

    Full Text Available Abstract Background We investigated fetal and total DNA levels in maternal plasma in patients bearing fetuses affected with Down syndrome in comparison to controls carrying fetuses with normal karyotype. Methods DNA levels in maternal plasma were measured using real-time quantitative PCR using SRY and β-globin genes as markers. Twenty-one pregnant women with a singleton fetus at a gestational age ranging from 15 to 19 weeks recruited before amniocentesis (carried out for reasons including material serum screening and advanced material age, and 16 pregnant women bearing fetuses affected with Down syndrome between 17 to 22 weeks of gestation were involved in the study. Results The specificity of the system reaches 100% (no Y signal was detected in 14 women pregnant with female fetuses and the sensitivity 91.7% (SRY amplification in 22 of 24 examined samples. The median fetal DNA levels in women carrying Down syndrome (n=11 and the controls (n=13 were 23.3 (range 0–58.5 genome-equivalents/ml and 24.5 (range 0–47.5 genome-equivalents/ml of maternal plasma, respectively (P = 0.62. The total median DNA levels in pregnancies with Down syndrome and the controls were 10165 (range 615–65000 genome-equivalents/ml and 7330 (range 1300–36750 genome-equivalents/ml, respectively (P = 0.32. The fetal DNA proportion in maternal plasma was 0%-6 % (mean 0.8% in women carrying Down syndrome and 0%-2.6 % (mean 0.7 % in the controls, respectively (P=0.86. Conclusions Our study revealed no difference in fetal DNA levels and fetal DNA: maternal DNA ratio between the patients carrying Down syndrome fetuses and the controls.

  11. A Quantitative ADME-base Tool for Exploring Human ...

    Science.gov (United States)

    Exposure to a wide range of chemicals through our daily habits and routines is ubiquitous and largely unavoidable within modern society. The potential for human exposure, however, has not been quantified for the vast majority of chemicals with wide commercial use. Creative advances in exposure science are needed to support efficient and effective evaluation and management of chemical risks, particularly for chemicals in consumer products. The U.S. Environmental Protection Agency Office of Research and Development is developing, or collaborating in the development of, scientifically-defensible methods for making quantitative or semi-quantitative exposure predictions. The Exposure Prioritization (Ex Priori) model is a simplified, quantitative visual dashboard that provides a rank-ordered internalized dose metric to simultaneously explore exposures across chemical space (not chemical by chemical). Diverse data streams are integrated within the interface such that different exposure scenarios for “individual,” “population,” or “professional” time-use profiles can be interchanged to tailor exposure and quantitatively explore multi-chemical signatures of exposure, internalized dose (uptake), body burden, and elimination. Ex Priori has been designed as an adaptable systems framework that synthesizes knowledge from various domains and is amenable to new knowledge/information. As such, it algorithmically captures the totality of exposure across pathways. It

  12. A probe-based quantitative PCR assay for detecting Tetracapsuloides bryosalmonae in fish tissue and environmental DNA water samples

    Science.gov (United States)

    Hutchins, Patrick; Sepulveda, Adam; Martin, Renee; Hopper, Lacey

    2017-01-01

    A probe-based quantitative real-time PCR assay was developed to detect Tetracapsuloides bryosalmonae, which causes proliferative kidney disease in salmonid fish, in kidney tissue and environmental DNA (eDNA) water samples. The limits of detection and quantification were 7 and 100 DNA copies for calibration standards and T. bryosalmonae was reliably detected down to 100 copies in tissue and eDNA samples. The assay presented here is a highly sensitive and quantitative tool for detecting T. bryosalmonae with potential applications for tissue diagnostics and environmental detection.

  13. Extraction of human nuclear DNA from feces samples using the QIAamp DNA Stool Mini Kit.

    Science.gov (United States)

    Vandenberg, Nicholas; van Oorschot, Roland A H

    2002-09-01

    The use of a QIAamp DNA Stool Mini Kit (QIAGEN) for extracting human nuclear DNA from feces samples is reported. This method employs a stool lysis buffer and a unique matrix (InhibitEX tablet) to remove PCR inhibitory substances specific to feces samples. DNA extracted from various amounts of stool and from stool samples exposed to different environmental impacts was successfully amplified and typed using the Profiler Plus Amplification Kit and ABI PRISM 310 Genetic Analyser.

  14. Analysis of JC virus DNA replication using a quantitative and high-throughput assay.

    Science.gov (United States)

    Shin, Jong; Phelan, Paul J; Chhum, Panharith; Bashkenova, Nazym; Yim, Sung; Parker, Robert; Gagnon, David; Gjoerup, Ole; Archambault, Jacques; Bullock, Peter A

    2014-11-01

    Progressive Multifocal Leukoencephalopathy (PML) is caused by lytic replication of JC virus (JCV) in specific cells of the central nervous system. Like other polyomaviruses, JCV encodes a large T-antigen helicase needed for replication of the viral DNA. Here, we report the development of a luciferase-based, quantitative and high-throughput assay of JCV DNA replication in C33A cells, which, unlike the glial cell lines Hs 683 and U87, accumulate high levels of nuclear T-ag needed for robust replication. Using this assay, we investigated the requirement for different domains of T-ag, and for specific sequences within and flanking the viral origin, in JCV DNA replication. Beyond providing validation of the assay, these studies revealed an important stimulatory role of the transcription factor NF1 in JCV DNA replication. Finally, we show that the assay can be used for inhibitor testing, highlighting its value for the identification of antiviral drugs targeting JCV DNA replication. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Quantitative PCR detection of Batrachochytrium dendrobatidis DNA from sediments and water

    Science.gov (United States)

    Kirshtein, J.D.; Anderson, C.W.; Wood, J.S.; Longcore, J.E.; Voytek, M.A.

    2007-01-01

    The fungal pathogen Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a disease implicated in amphibian declines on 5 continents. Polymerase chain reaction (PCR) primer sets exist with which amphibians can be tested for this disease, and advances in sampling techniques allow non-invasive testing of animals. We developed filtering and PCR based quantitative methods by modifying existing PCR assays to detect Bd DNA in water and sediments, without the need for testing amphibians; we tested the methods at 4 field sites. The SYBR based assay using Boyle primers (SYBR/Boyle assay) and the Taqman based assay using Wood primers performed similarly with samples generated in the laboratory (Bd spiked filters), but the SYBR/Boyle assay detected Bd DNA in more field samples. We detected Bd DNA in water from 3 of 4 sites tested, including one pond historically negative for chytridiomycosis. Zoospore equivalents in sampled water ranged from 19 to 454 l-1 (nominal detection limit is 10 DNA copies, or about 0.06 zoospore). We did not detect DNA of Bd from sediments collected at any sites. Our filtering and amplification methods provide a new tool to investigate critical aspects of Bd in the environment. ?? Inter-Research 2007.

  16. Combinatorial modeling of chromatin features quantitatively predicts DNA replication timing in Drosophila.

    Directory of Open Access Journals (Sweden)

    Federico Comoglio

    2014-01-01

    Full Text Available In metazoans, each cell type follows a characteristic, spatio-temporally regulated DNA replication program. Histone modifications (HMs and chromatin binding proteins (CBPs are fundamental for a faithful progression and completion of this process. However, no individual HM is strictly indispensable for origin function, suggesting that HMs may act combinatorially in analogy to the histone code hypothesis for transcriptional regulation. In contrast to gene expression however, the relationship between combinations of chromatin features and DNA replication timing has not yet been demonstrated. Here, by exploiting a comprehensive data collection consisting of 95 CBPs and HMs we investigated their combinatorial potential for the prediction of DNA replication timing in Drosophila using quantitative statistical models. We found that while combinations of CBPs exhibit moderate predictive power for replication timing, pairwise interactions between HMs lead to accurate predictions genome-wide that can be locally further improved by CBPs. Independent feature importance and model analyses led us to derive a simplified, biologically interpretable model of the relationship between chromatin landscape and replication timing reaching 80% of the full model accuracy using six model terms. Finally, we show that pairwise combinations of HMs are able to predict differential DNA replication timing across different cell types. All in all, our work provides support to the existence of combinatorial HM patterns for DNA replication and reveal cell-type independent key elements thereof, whose experimental investigation might contribute to elucidate the regulatory mode of this fundamental cellular process.

  17. Analysis of JC virus DNA replication using a quantitative and high-throughput assay

    Science.gov (United States)

    Shin, Jong; Phelan, Paul J.; Chhum, Panharith; Bashkenova, Nazym; Yim, Sung; Parker, Robert; Gagnon, David; Gjoerup, Ole; Archambault, Jacques; Bullock, Peter A.

    2015-01-01

    Progressive Multifocal Leukoencephalopathy (PML) is caused by lytic replication of JC virus (JCV) in specific cells of the central nervous system. Like other polyomaviruses, JCV encodes a large T-antigen helicase needed for replication of the viral DNA. Here, we report the development of a luciferase-based, quantitative and high-throughput assay of JCV DNA replication in C33A cells, which, unlike the glial cell lines Hs 683 and U87, accumulate high levels of nuclear T-ag needed for robust replication. Using this assay, we investigated the requirement for different domains of T-ag, and for specific sequences within and flanking the viral origin, in JCV DNA replication. Beyond providing validation of the assay, these studies revealed an important stimulatory role of the transcription factor NF1 in JCV DNA replication. Finally, we show that the assay can be used for inhibitor testing, highlighting its value for the identification of antiviral drugs targeting JCV DNA replication. PMID:25155200

  18. Characterization of circulating DNA in healthy human plasma.

    Science.gov (United States)

    Suzuki, Nobuyasu; Kamataki, Akihisa; Yamaki, Junko; Homma, Yoshimi

    2008-01-01

    The importance of circulating DNA has been recognized since the detection of mutated oncogene products in cancer patients; however, there is little information about circulating DNA in normal human plasma. We characterized circulating DNA in normal human plasma to obtain basic information. Circulating DNA was purified from plasma samples obtained from 10 healthy donors and examined. Purified DNA was cloned and their sequence determined and analyzed. The terminal structure was examined by a labeling method. The DNA levels in normal plasma samples were quite low (3.6-5.0 ng/ml). All 556 clones analyzed were independent, and obtained from various chromosomes and various regions of the gene. The mean values of their length and GC content were 176 bp and 53.7%, respectively. Their 5' and 3' ends were rich in C and G, respectively, and they presented as 5' protruding forms of double-stranded DNA in plasma. Circulating DNA in normal human plasma is derived from apoptotic cells but not from necrotic cells. Structural characteristics of the circulating DNA might be associated with their stability in plasma.

  19. DNA and bone structure preservation in medieval human skeletons.

    Science.gov (United States)

    Coulson-Thomas, Yvette M; Norton, Andrew L; Coulson-Thomas, Vivien J; Florencio-Silva, Rinaldo; Ali, Nadir; Elmrghni, Samir; Gil, Cristiane D; Sasso, Gisela R S; Dixon, Ronald A; Nader, Helena B

    2015-06-01

    Morphological and ultrastructural data from archaeological human bones are scarce, particularly data that have been correlated with information on the preservation of molecules such as DNA. Here we examine the bone structure of macroscopically well-preserved medieval human skeletons by transmission electron microscopy and immunohistochemistry, and the quantity and quality of DNA extracted from these skeletons. DNA technology has been increasingly used for analyzing physical evidence in archaeological forensics; however, the isolation of ancient DNA is difficult since it is highly degraded, extraction yields are low and the co-extraction of PCR inhibitors is a problem. We adapted and optimised a method that is frequently used for isolating DNA from modern samples, Chelex(®) 100 (Bio-Rad) extraction, for isolating DNA from archaeological human bones and teeth. The isolated DNA was analysed by real-time PCR using primers targeting the sex determining region on the Y chromosome (SRY) and STR typing using the AmpFlSTR(®) Identifiler PCR Amplification kit. Our results clearly show the preservation of bone matrix in medieval bones and the presence of intact osteocytes with well preserved encapsulated nuclei. In addition, we show how effective Chelex(®) 100 is for isolating ancient DNA from archaeological bones and teeth. This optimised method is suitable for STR typing using kits aimed specifically at degraded and difficult DNA templates since amplicons of up to 250bp were successfully amplified. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  20. Markov chain for estimating human mitochondrial DNA mutation pattern

    Science.gov (United States)

    Vantika, Sandy; Pasaribu, Udjianna S.

    2015-12-01

    The Markov chain was proposed to estimate the human mitochondrial DNA mutation pattern. One DNA sequence was taken randomly from 100 sequences in Genbank. The nucleotide transition matrix and mutation transition matrix were estimated from this sequence. We determined whether the states (mutation/normal) are recurrent or transient. The results showed that both of them are recurrent.

  1. DNA content in human uterine cervical dysplasias.

    Science.gov (United States)

    Palan, P R; Romney, S L

    1979-01-01

    The DNA content of nuclei extracted from separate biopsies of normal cervical epithelium and from dysplastic sites in the same patient was determined biochemically. Mean percentage increase in the DNA content of dysplasias (mild: 143.3 +/- 14.9; moderate: 225.8 +/- 51.1; and severe: 359.8 +/- 45.8) was found to be statistically significant (F-Test: p less than 0.001) over the normal values in control cervical tissues.

  2. Artificial Intelligence, DNA Mimicry, and Human Health.

    Science.gov (United States)

    Stefano, George B; Kream, Richard M

    2017-08-14

    The molecular evolution of genomic DNA across diverse plant and animal phyla involved dynamic registrations of sequence modifications to maintain existential homeostasis to increasingly complex patterns of environmental stressors. As an essential corollary, driver effects of positive evolutionary pressure are hypothesized to effect concerted modifications of genomic DNA sequences to meet expanded platforms of regulatory controls for successful implementation of advanced physiological requirements. It is also clearly apparent that preservation of updated registries of advantageous modifications of genomic DNA sequences requires coordinate expansion of convergent cellular proofreading/error correction mechanisms that are encoded by reciprocally modified genomic DNA. Computational expansion of operationally defined DNA memory extends to coordinate modification of coding and previously under-emphasized noncoding regions that now appear to represent essential reservoirs of untapped genetic information amenable to evolutionary driven recruitment into the realm of biologically active domains. Additionally, expansion of DNA memory potential via chemical modification and activation of noncoding sequences is targeted to vertical augmentation and integration of an expanded cadre of transcriptional and epigenetic regulatory factors affecting linear coding of protein amino acid sequences within open reading frames.

  3. Abstracts of papers presented at the LVIII Cold Spring Harbor Symposium on quantitative Biology: DNA and chromosomes

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-31

    This volume contains the abstracts of oral and poster presentations made at the LVIII Cold Spring Harbor Symposium on Quantitative Biology entitles DNA & Chromosomes. The meeting was held June 2--June 9, 1993 at Cold Spring Harbor, New York.

  4. Mitochondrial DNA as a non-invasive biomarker: Accurate quantification using real time quantitative PCR without co-amplification of pseudogenes and dilution bias

    Energy Technology Data Exchange (ETDEWEB)

    Malik, Afshan N., E-mail: afshan.malik@kcl.ac.uk [King' s College London, Diabetes Research Group, Division of Diabetes and Nutritional Sciences, School of Medicine (United Kingdom); Shahni, Rojeen; Rodriguez-de-Ledesma, Ana; Laftah, Abas; Cunningham, Phil [King' s College London, Diabetes Research Group, Division of Diabetes and Nutritional Sciences, School of Medicine (United Kingdom)

    2011-08-19

    Highlights: {yields} Mitochondrial dysfunction is central to many diseases of oxidative stress. {yields} 95% of the mitochondrial genome is duplicated in the nuclear genome. {yields} Dilution of untreated genomic DNA leads to dilution bias. {yields} Unique primers and template pretreatment are needed to accurately measure mitochondrial DNA content. -- Abstract: Circulating mitochondrial DNA (MtDNA) is a potential non-invasive biomarker of cellular mitochondrial dysfunction, the latter known to be central to a wide range of human diseases. Changes in MtDNA are usually determined by quantification of MtDNA relative to nuclear DNA (Mt/N) using real time quantitative PCR. We propose that the methodology for measuring Mt/N needs to be improved and we have identified that current methods have at least one of the following three problems: (1) As much of the mitochondrial genome is duplicated in the nuclear genome, many commonly used MtDNA primers co-amplify homologous pseudogenes found in the nuclear genome; (2) use of regions from genes such as {beta}-actin and 18S rRNA which are repetitive and/or highly variable for qPCR of the nuclear genome leads to errors; and (3) the size difference of mitochondrial and nuclear genomes cause a 'dilution bias' when template DNA is diluted. We describe a PCR-based method using unique regions in the human mitochondrial genome not duplicated in the nuclear genome; unique single copy region in the nuclear genome and template treatment to remove dilution bias, to accurately quantify MtDNA from human samples.

  5. Babesia bigemina: quantitation of infection in nymphal and adult Boophilus microplus using a DNA probe.

    Science.gov (United States)

    Hodgson, J L; Stiller, D; Jasmer, D P; Buening, G M; Wagner, G G; McGuire, T C

    1992-02-01

    Candidates for a subunit vaccine against bovine babesiosis include surface proteins of infective forms found in the salivary glands of tick vectors. However, low numbers of infective forms are present within ticks and hinder analysis of this stage. To solve this problem, conditions which yield high numbers of infective forms were investigated with the use of a Babesia bigemina-specific DNA probe. DNA from progeny of female Boophilus microplus infected with B. bigemina was hybridized to probe DNA to detect and quantitate infection. There was no difference in the prevalence of infection in progeny of three strains of Bo. microplus. However, within a strain, prevalence could be increased to 30% by combining selection of progeny from heavily (3+) infected female ticks and selection of eggs laid 120 hr postengorgement. Quantitation of infective forms within pooled salivary gland preparations of 10 infected nymphal and adult Bo. microplus demonstrated that Day 9 and 10 nymphal ticks contained the highest numbers of parasites and represented approximately 10(6) infective forms. This number of infective forms is suitable for isolation and further characterization.

  6. Interaction of clinically important human DNA topoisomerase I poison, topotecan, with double-stranded DNA.

    Science.gov (United States)

    Streltsov, Sergei; Oleinikov, Vladimir; Ermishov, Mikhail; Mochalov, Konstantin; Sukhanova, Alyona; Nechipurenko, Yuri; Grokhovsky, Sergei; Zhuze, Alexei; Pluot, Michel; Nabiev, Igor

    2003-01-01

    Topotecan (TPT), a water-soluble derivative of camptothecin, is a potent antitumor poison of human DNA topoisomerase I (top1) that stabilizes the cleavage complex between the enzyme and DNA. The role of the recently discovered TPT affinity to DNA remains to be defined. The aim of this work is to clarify the molecular mechanisms of the TPT-DNA interaction and to propose the models of TPT-DNA complexes in solution in the absence of top1. It is shown that TPT molecules form dimers with a dimerization constant of (4.0 +/- 0.7) x 10(3) M(-1) and the presence of DNA provokes more than a 400-fold increase of the effective dimerization constant. Flow linear dichroism spectroscopy accompanied by circular dichroism, fluorescence, and surface-enhanced Raman scattering experiments provide evidence that TPT dimers are able to bind DNA by bridging different DNA molecules or distant DNA structural domains. This effect may provoke modification of the intrinsic geometry of the cruciform DNA structures, leading to the appearance of new crossover points that serve as the sites of the top1 loading position. The data presume the hypothesis of TPT-mediated modulation of top1-DNA recognition before ternary complex formation. Copyright 2003 Wiley Periodicals, Inc.

  7. Quantitative real-time PCR technique for the identification of E. coli residual DNA in streptokinase recombinant product.

    Science.gov (United States)

    Fazelahi, Mansoureh; Kia, Vahid; Kaghazian, Hooman; Paryan, Mahdi

    2017-11-26

    Recombinant streptokinase is a biopharmaceutical which is usually produced in E. coli. Residual DNA as a contamination and risk factor may remain in the product. It is necessary to control the production procedure to exclude any possible contamination. The aim of the present study was to develop a highly specific and sensitive quantitative real-time PCR-based method to determine the amount of E. coli DNA in recombinant streptokinase. A specific primers and a probe was designed to detect all strains of E. coli. To determine the specificity, in addition to using NCBI BLASTn, 28 samples including human, bacterial, and viral genomes were used. The results confirmed that the assay detects no genomic DNA but E. coli's and the specificity was determined to be 100%. To determine the sensitivity and limit of detection of the assay, a 10-fold serial dilution (10 1 to 10 7 copies/µL) was tested in triplicate. The sensitivity of the test was determined to be 101 copies/µL or 35 fg/µL. Inter-assay and intra-assay were determined to be 0.86 and 1.69%, respectively. Based on the results, this assay can be used as an accurate method to evaluate the contamination of recombinant streptokinase in E. coli.

  8. A DNA methylation fingerprint of 1628 human samples

    Science.gov (United States)

    Fernandez, Agustin F.; Assenov, Yassen; Martin-Subero, Jose Ignacio; Balint, Balazs; Siebert, Reiner; Taniguchi, Hiroaki; Yamamoto, Hiroyuki; Hidalgo, Manuel; Tan, Aik-Choon; Galm, Oliver; Ferrer, Isidre; Sanchez-Cespedes, Montse; Villanueva, Alberto; Carmona, Javier; Sanchez-Mut, Jose V.; Berdasco, Maria; Moreno, Victor; Capella, Gabriel; Monk, David; Ballestar, Esteban; Ropero, Santiago; Martinez, Ramon; Sanchez-Carbayo, Marta; Prosper, Felipe; Agirre, Xabier; Fraga, Mario F.; Graña, Osvaldo; Perez-Jurado, Luis; Mora, Jaume; Puig, Susana; Prat, Jaime; Badimon, Lina; Puca, Annibale A.; Meltzer, Stephen J.; Lengauer, Thomas; Bridgewater, John; Bock, Christoph; Esteller, Manel

    2012-01-01

    Most of the studies characterizing DNA methylation patterns have been restricted to particular genomic loci in a limited number of human samples and pathological conditions. Herein, we present a compromise between an extremely comprehensive study of a human sample population with an intermediate level of resolution of CpGs at the genomic level. We obtained a DNA methylation fingerprint of 1628 human samples in which we interrogated 1505 CpG sites. The DNA methylation patterns revealed show this epigenetic mark to be critical in tissue-type definition and stemness, particularly around transcription start sites that are not within a CpG island. For disease, the generated DNA methylation fingerprints show that, during tumorigenesis, human cancer cells underwent a progressive gain of promoter CpG-island hypermethylation and a loss of CpG methylation in non-CpG-island promoters. Although transformed cells are those in which DNA methylation disruption is more obvious, we observed that other common human diseases, such as neurological and autoimmune disorders, had their own distinct DNA methylation profiles. Most importantly, we provide proof of principle that the DNA methylation fingerprints obtained might be useful for translational purposes by showing that we are able to identify the tumor type origin of cancers of unknown primary origin (CUPs). Thus, the DNA methylation patterns identified across the largest spectrum of samples, tissues, and diseases reported to date constitute a baseline for developing higher-resolution DNA methylation maps and provide important clues concerning the contribution of CpG methylation to tissue identity and its changes in the most prevalent human diseases. PMID:21613409

  9. Mouse DNA contamination in human tissue tested for XMRV.

    Science.gov (United States)

    Robinson, Mark J; Erlwein, Otto W; Kaye, Steve; Weber, Jonathan; Cingoz, Oya; Patel, Anup; Walker, Marjorie M; Kim, Wun-Jae; Uiprasertkul, Mongkol; Coffin, John M; McClure, Myra O

    2010-12-20

    We used a PCR-based approach to study the prevalence of genetic sequences related to a gammaretrovirus, xenotropic murine leukemia virus-related virus, XMRV, in human prostate cancer. This virus has been identified in the US in prostate cancer patients and in those with chronic fatigue syndrome. However, with the exception of two patients in Germany, XMRV has not been identified in prostate cancer tissue in Europe. Most putative associations of new or old human retroviruses with diseases have turned out to be due to contamination. We have looked for XMRV sequences in DNA extracted from formalin-fixed paraffin- embedded prostate tissues. To control for contamination, PCR assays to detect either mouse mitochondrial DNA (mtDNA) or intracisternal A particle (IAP) long terminal repeat DNA were run on all samples, owing to their very high copy number in mouse cells. In general agreement with the US prevalence, XMRV-like sequences were found in 4.8% of prostate cancers. However, these were also positive, as were 21.5% of XMRV-negative cases, for IAP sequences, and many, but not all were positive for mtDNA sequences. These results show that contamination with mouse DNA is widespread and detectable by the highly sensitive IAP assay, but not always with less sensitive assays, such as murine mtDNA PCR. This study highlights the ubiquitous presence of mouse DNA in laboratory specimens and offers a means of rigorous validation for future studies of murine retroviruses in human disease.

  10. Rapid extraction and preservation of genomic DNA from human samples.

    Science.gov (United States)

    Kalyanasundaram, D; Kim, J-H; Yeo, W-H; Oh, K; Lee, K-H; Kim, M-H; Ryew, S-M; Ahn, S-G; Gao, D; Cangelosi, G A; Chung, J-H

    2013-02-01

    Simple and rapid extraction of human genomic DNA remains a bottleneck for genome analysis and disease diagnosis. Current methods using microfilters require cumbersome, multiple handling steps in part because salt conditions must be controlled for attraction and elution of DNA in porous silica. We report a novel extraction method of human genomic DNA from buccal swab and saliva samples. DNA is attracted onto a gold-coated microchip by an electric field and capillary action while the captured DNA is eluted by thermal heating at 70 °C. A prototype device was designed to handle four microchips, and a compatible protocol was developed. The extracted DNA using microchips was characterized by qPCR for different sample volumes, using different lengths of PCR amplicon, and nuclear and mitochondrial genes. In comparison with a commercial kit, an equivalent yield of DNA extraction was achieved with fewer steps. Room-temperature preservation for 1 month was demonstrated for captured DNA, facilitating straightforward collection, delivery, and handling of genomic DNA in an environment-friendly protocol.

  11. Human exonuclease 1 and BLM helicase interact to resect DNA and initiate DNA repair

    Science.gov (United States)

    Nimonkar, Amitabh V.; Özsoy, A. Zeynep; Genschel, Jochen; Modrich, Paul; Kowalczykowski, Stephen C.

    2008-01-01

    The error-free repair of double-stranded DNA breaks by homologous recombination requires processing of broken ends. These processed ends are substrates for assembly of DNA strand exchange proteins that mediate DNA strand invasion. Here, we establish that human BLM helicase, a member of the RecQ family, stimulates the nucleolytic activity of human exonuclease 1 (hExo1), a 5′→3′ double-stranded DNA exonuclease. The stimulation is specific because other RecQ homologs fail to stimulate hExo1. Stimulation of DNA resection by hExo1 is independent of BLM helicase activity and is, instead, mediated by an interaction between the 2 proteins. Finally, we show that DNA ends resected by hExo1 and BLM are used by human Rad51, but not its yeast or bacterial counterparts, to promote homologous DNA pairing. This in vitro system recapitulates initial steps of homologous recombination and provides biochemical evidence for a role of BLM and Exo1 in the initiation of recombinational DNA repair. PMID:18971343

  12. Recovery of DNA from human teeth by cryogenic grinding.

    Science.gov (United States)

    Sweet, D; Hildebrand, D

    1998-11-01

    DNA has been previously recovered from human teeth for RFLP and PCR-based forensic analysis. In some cases, the maximum amount of undisturbed tooth structure is required for ulterior forensic analysis. But, in most cases, following comprehensive documentation, it is possible to section the tooth longitudinally or horizontally, or crush it to access the DNA-rich core. This technical report describes an alternative method to recover DNA from whole extracted human molar teeth. A 6700 freezer mill was used to pulverize 20 teeth under frozen preparation in liquid nitrogen and sterile conditions. The mean yield of DNA was 30.9 micrograms (18.4 micrograms DNA per gm tooth powder). The resulting fine powder was subjected to organic extraction and subsequently quantified using slot blot hybridization. Aliquots were successfully amplified at three short tandem repeat polymorphic loci. The technique is simple and relatively rapid. Isolation of the samples during pulverization minimizes the risk of contamination.

  13. Analysis of epigenetic modifications of DNA in human cells

    DEFF Research Database (Denmark)

    Kristensen, Lasse Sommer; Treppendahl, Marianne Bach; Grønbæk, Kirsten

    2013-01-01

    Epigenetics, the study of somatically heritable changes in gene expression not related to changes in the DNA sequence, is a rapidly expanding research field that plays important roles in healthy as well as in diseased cells. DNA methylation and hydroxymethylation are epigenetic modifications found...... in human cells, which are deeply implicated in normal cellular processes as well as in several major human diseases. Here, a range of different methods for the analyses of DNA methylation and hydroxymethylation at locus-specific and genome-wide scales is described....

  14. A rapid DNA extraction method suitable for human papillomavirus detection.

    Science.gov (United States)

    Brestovac, Brian; Wong, Michelle E; Costantino, Paul S; Groth, David

    2014-04-01

    Infection with oncogenic human papillomavirus (HPV) genotypes is necessary for the development of cervical cancer. Testing for HPV DNA from liquid based cervical samples can be used as an adjunct to traditional cytological screening. In addition there are ongoing viral load, genotyping, and prevalence studies. Therefore, a sensitive DNA extraction method is needed to maximize the efficiency of HPV DNA detection. The XytXtract Tissue kit is a DNA extraction kit that is rapid and so could be useful for HPV testing, particularly in screening protocols. This study was undertaken to determine the suitability of this method for HPV detection. DNA extraction from HeLa and Caski cell lines containing HPV 18 and 16 respectively together with DNA from five liquid based cervical samples were used in a HPV PCR assay. DNA was also extracted using the QIAamp DNA mini kit (Qiagen, Hilden, Germany) as a comparison. DNA extracts were serially diluted and assayed. HPV DNA was successfully detected in cell lines and cervical samples using the XytXtract Tissue kit. In addition, the XytXtract method was found to be more sensitive than the QIAmp method as determined by a dilution series of the extracted DNA. While the XytXtract method is a closed, the QIAamp method uses a spin column with possible loss of DNA through DNA binding competition of the matrix, which could impact on the final extraction efficiency. The XytXtract is a cheap, rapid and efficient method for extracting HPV DNA from both cell lines and liquid based cervical samples. © 2014 Wiley Periodicals, Inc.

  15. Mitochondrial DNA deletion associated with the reduction of adenine nucleotides in human atrium and atrial fibrillation.

    Science.gov (United States)

    Tsuboi, M; Hisatome, I; Morisaki, T; Tanaka, M; Tomikura, Y; Takeda, S; Shimoyama, M; Ohtahara, A; Ogino, K; Igawa, O; Shigemasa, C; Ohgi, S; Nanba, E

    2001-06-01

    Structural changes in the number, size, and shape of mitochondria (mt) have been observed in the atrial muscles of patients with atrial fibrillation (AF) and of animals with rapid atrial pacing, however, it is not known whether the mitochondrial function is impaired in human atrium with AF. We determined adenine nucleotides concentrations and mtDNA deletions in 26 human right atria obtained at the time of cardiac surgery, using HPLC and PCR amplification, and studied the relationship between mtDNA deletions and clinical manifestations, the haemodynamic parameters of the patients and adenine nucleotide concentrations in their atrium. The age and the prevalence of AF were significantly higher in the patients with a mtDNA deletion of 7.4 kb than in those without a deletion; there were no significant differences regarding haemodynamic parameters between the two groups. The concentrations of ATP, ADP, AMP and total adenine nucleotides in the right atrium were significantly lower in the patients with mtDNA deletions than the patients without a deletion. In a gender- and diseased-matched population, the mtDNA deletion was still significantly associated with age and a decreased concentration of adenine nucleotides in the atrium. Using quantitative PCR analysis, the proportion of mtDNA deletion to normal mtDNA of the atrium, was estimated to be 0.3-2% in four cases. These results suggest that the deletion of mtDNA associated with ageing or AF can lead to a bioenergetic deficiency due to an impaired ATP synthesis in the human atrium; however, no conclusion can be made whether mtDNA deletion were the result or the cause of an impaired ATP synthesis, ageing, hemodynamic deterioration, or AF.

  16. Human DNA polymerase θ grasps the primer terminus to mediate DNA repair.

    Science.gov (United States)

    Zahn, Karl E; Averill, April M; Aller, Pierre; Wood, Richard D; Doublié, Sylvie

    2015-04-01

    DNA polymerase θ protects against genomic instability via an alternative end-joining repair pathway for DNA double-strand breaks. Polymerase θ is overexpressed in breast, lung and oral cancers, and reduction of its activity in mammalian cells increases sensitivity to double-strand break-inducing agents, including ionizing radiation. Reported here are crystal structures of the C-terminal polymerase domain from human polymerase θ, illustrating two potential modes of dimerization. One structure depicts insertion of ddATP opposite an abasic-site analog during translesion DNA synthesis. The second structure describes a cognate ddGTP complex. Polymerase θ uses a specialized thumb subdomain to establish unique upstream contacts to the primer DNA strand, including an interaction with the 3'-terminal phosphate from one of five distinctive insertion loops. These observations demonstrate how polymerase θ grasps the primer to bypass DNA lesions or extend poorly annealed DNA termini to mediate end-joining.

  17. Evaluating the weight of evidence by using quantitative short tandem repeat data in DNA mixtures

    DEFF Research Database (Denmark)

    Tvedebrink, Torben; Eriksen, Poul Svante; Mogensen, Helle Smidt

    2010-01-01

    he evaluation of results from mixtures of deoxyribonucleic acid (DNA) from two or more people in crime case investigations may be improved by taking not only the qualitative but also the quantitative part of the results into consideration. We present a statistical likelihood approach to assess...... distribution of peak areas for assessing the weight of the evidence. On the basis of data from analyses of controlled experiments with mixed DNA samples, we exploited the linear relationship between peak heights and peak areas, and the linear relationships of the means and variances of the measurements...... to factorization of the likelihood, properties of the normal distribution and use of auxiliary variables, an ordinary implementation of the EM algorithm solved the missing data problem....

  18. The Human Cytomegalovirus UL44 C Clamp Wraps around DNA

    Science.gov (United States)

    Komazin-Meredith, Gloria; Petrella, Robert J.; Santos, Webster L.; Filman, David J.; Hogle, James M.; Verdine, Gregory L.; Karplus, Martin; Coen, Donald M.

    2010-01-01

    Summary Processivity factors tether the catalytic subunits of DNA polymerases to DNA so that continuous synthesis of long DNA strands is possible. The human cytomegalovirus DNA polymerase subunit UL44 forms a C clamp-shaped dimer intermediate in structure between monomeric herpes simplex virus UL42, which binds DNA directly via a basic surface, and the trimeric sliding clamp PCNA, which encircles DNA. To investigate how UL44 interacts with DNA, calculations were performed in which a 12 bp DNA oligonucleotide was docked to UL44. The calculations suggested that UL44 encircles DNA, which interacts with basic residues both within the cavity of the C clamp and in flexible loops of UL44 that complete the “circle.” The results of mutational and crosslinking studies were consistent with this model. Thus, UL44 is a “hybrid” of UL42 and PCNA: its structure is intermediate between the two and its mode of interaction with DNA has elements of both. PMID:18682223

  19. Quantitative Modeling of Human-Environment Interactions in Preindustrial Time

    Science.gov (United States)

    Sommer, Philipp S.; Kaplan, Jed O.

    2017-04-01

    Quantifying human-environment interactions and anthropogenic influences on the environment prior to the Industrial revolution is essential for understanding the current state of the earth system. This is particularly true for the terrestrial biosphere, but marine ecosystems and even climate were likely modified by human activities centuries to millennia ago. Direct observations are however very sparse in space and time, especially as one considers prehistory. Numerical models are therefore essential to produce a continuous picture of human-environment interactions in the past. Agent-based approaches, while widely applied to quantifying human influence on the environment in localized studies, are unsuitable for global spatial domains and Holocene timescales because of computational demands and large parameter uncertainty. Here we outline a new paradigm for the quantitative modeling of human-environment interactions in preindustrial time that is adapted to the global Holocene. Rather than attempting to simulate agency directly, the model is informed by a suite of characteristics describing those things about society that cannot be predicted on the basis of environment, e.g., diet, presence of agriculture, or range of animals exploited. These categorical data are combined with the properties of the physical environment in coupled human-environment model. The model is, at its core, a dynamic global vegetation model with a module for simulating crop growth that is adapted for preindustrial agriculture. This allows us to simulate yield and calories for feeding both humans and their domesticated animals. We couple this basic caloric availability with a simple demographic model to calculate potential population, and, constrained by labor requirements and land limitations, we create scenarios of land use and land cover on a moderate-resolution grid. We further implement a feedback loop where anthropogenic activities lead to changes in the properties of the physical

  20. Optimization and validation of DNA extraction and real-time PCR assay for the quantitative measurement of residual host cell DNA in biopharmaceutical products.

    Science.gov (United States)

    Hu, B; Sellers, J; Kupec, J; Ngo, W; Fenton, S; Yang, T-Y; Grebanier, A

    2014-01-01

    Host cell DNA contamination occurs during the production of biopharmaceuticals and must be controlled and monitored for the purity and safety of the drug products. A sodium iodide-based DNA extraction and a subsequent real time PCR assay were developed and validated for the quantitative measurement of residual host cell DNA impurity in monoclonal antibody therapeutic products. A sodium iodide-based commercial kit was optimized for the removal of interfering matrices. Several incubation steps from the kit protocol were combined and a neutralization buffer was introduced to protein digestion step to eliminate any precipitation from the detergent. The elimination of the two washing steps significantly reduced assay variability from loss of DNA pellets. The optimized DNA extraction procedure can recover DNA close to 100% for DNA concentrations from 10 to 100,000pg/mL. Of the published sequences of repetitive interspersed nuclear elements, we identified a nucleotide mismatch from the published CHO probe. Correction of this nucleotide increased DNA amplification by a thousand fold. The optimized assay was further validated for the quantitation of residual CHO DNA according to ICH guidelines with preset assay acceptance criteria. The method met all assay acceptance criteria and was found linear, accurate and precise for the quantitation of residual CHO in the linear range of 10-100,000pg DNA/mL. LOQ was measured at 10pg DNA/mL and LOD at 1pg DNA/mL. No matrix interference to our validated assay was detected from bioreactor harvest, Protein A eluate or eluate from ion exchange columns. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. A DNA Vaccine Protects Human Immune Cells against Zika Virus Infection in Humanized Mice

    Directory of Open Access Journals (Sweden)

    Guohua Yi

    2017-11-01

    Full Text Available A DNA vaccine encoding prM and E protein has been shown to induce protection against Zika virus (ZIKV infection in mice and monkeys. However, its effectiveness in humans remains undefined. Moreover, identification of which immune cell types are specifically infected in humans is unclear. We show that human myeloid cells and B cells are primary targets of ZIKV in humanized mice. We also show that a DNA vaccine encoding full length prM and E protein protects humanized mice from ZIKV infection. Following administration of the DNA vaccine, humanized DRAG mice developed antibodies targeting ZIKV as measured by ELISA and neutralization assays. Moreover, following ZIKV challenge, vaccinated animals presented virtually no detectable virus in human cells and in serum, whereas unvaccinated animals displayed robust infection, as measured by qRT-PCR. Our results utilizing humanized mice show potential efficacy for a targeted DNA vaccine against ZIKV in humans.

  2. Human DNA ligase III bridges two DNA ends to promote specific intermolecular DNA end joining

    Science.gov (United States)

    Kukshal, Vandna; Kim, In-Kwon; Hura, Gregory L.; Tomkinson, Alan E.; Tainer, John A.; Ellenberger, Tom

    2015-01-01

    Mammalian DNA ligase III (LigIII) functions in both nuclear and mitochondrial DNA metabolism. In the nucleus, LigIII has functional redundancy with DNA ligase I whereas LigIII is the only mitochondrial DNA ligase and is essential for the survival of cells dependent upon oxidative respiration. The unique LigIII zinc finger (ZnF) domain is not required for catalytic activity but senses DNA strand breaks and stimulates intermolecular ligation of two DNAs by an unknown mechanism. Consistent with this activity, LigIII acts in an alternative pathway of DNA double strand break repair that buttresses canonical non-homologous end joining (NHEJ) and is manifest in NHEJ-defective cancer cells, but how LigIII acts in joining intermolecular DNA ends versus nick ligation is unclear. To investigate how LigIII efficiently joins two DNAs, we developed a real-time, fluorescence-based assay of DNA bridging suitable for high-throughput screening. On a nicked duplex DNA substrate, the results reveal binding competition between the ZnF and the oligonucleotide/oligosaccharide-binding domain, one of three domains constituting the LigIII catalytic core. In contrast, these domains collaborate and are essential for formation of a DNA-bridging intermediate by adenylated LigIII that positions a pair of blunt-ended duplex DNAs for efficient and specific intermolecular ligation. PMID:26130724

  3. Damage-specific DNA-binding proteins from human cells

    Energy Technology Data Exchange (ETDEWEB)

    Kanjilal, S.

    1992-01-01

    The primary objective of the study was to detect and characterize factors from human cells that bind DNA damaged by ultraviolet radiation. An application of the gel-shift assay was devised in which a DNA probe was UV-irradiated and compared with non-irradiated probe DNA for the ability to bind to such factors in cell extracts. UV-dose dependent binding proteins were identified. Formation of the DNA-protein complexes was independent of the specific sequence, form or source of the DNA. There was a marked preference for lesions on double stranded DNA over those on single stranded DNA. DNA irradiated with gamma rays did not compete with UV-irradiated DNA for the binding activities. Cell lines from patients with genetic diseases associated with disorders of the DNA repair system were screened for the presence of damaged-DNA-binding activities. Simultaneous occurrence of the clinical symptoms of some of these diseases had been previously documented and possible links between the syndromes proposed. However, supporting biochemical or molecular evidence for such associations were lacking. The data from the present investigations indicate that some cases of Xeroderma Pigmentosum group A, Cockayne's Syndrome, Bloom's Syndrome and Ataxia Telangiectasia, all of which exhibit sensitivity to UV or gamma radiation, share an aberrant damaged-DNA-binding factor. These findings support the hypothesis that some of the repair disorder diseases are closely related and may have arisen from a common defect. Partial purification of the binding activities from HeLa cells was achieved. Size-exclusion chromatography resolved the activities into various peaks, one of which was less damage-specific than the others as determined by competition studies using native or UV-irradiated DNA. Some of the activities were further separated by ion-exchange chromatography. On using affinity chromatography methods, the major damage-binding factor could be eluted in the presence of 2 M KCl and 1

  4. The impact of methylation quantitative trait loci (mQTLs) on active smoking-related DNA methylation changes.

    Science.gov (United States)

    Gao, Xu; Thomsen, Hauke; Zhang, Yan; Breitling, Lutz Philipp; Brenner, Hermann

    2017-01-01

    Methylation quantitative trait loci (mQTLs) are the genetic variants that may affect the DNA methylation patterns of CpG sites. However, their roles in influencing the disturbances of smoking-related epigenetic changes have not been well established. This study was conducted to address whether mQTLs exist in the vicinity of smoking-related CpG sites (± 50 kb) and to examine their associations with smoking exposure and all-cause mortality in older adults. We obtained DNA methylation profiles in whole blood samples by Illumina Infinium Human Methylation 450 BeadChip array of two independent subsamples of the ESTHER study (discovery set, n = 581; validation set, n = 368) and their corresponding genotyping data using the Illumina Infinium OncoArray BeadChip. After correction for multiple testing (FDR), we successfully identified that 70 out of 151 previously reported smoking-related CpG sites were significantly associated with 192 SNPs within the 50 kb search window of each locus. The 192 mQTLs significantly influenced the active smoking-related DNA methylation changes, with percentage changes ranging from 0.01 to 18.96%, especially for the weakly/moderately smoking-related CpG sites. However, these identified mQTLs were not directly associated with active smoking exposure or all-cause mortality. Our findings clearly demonstrated that if not dealt with properly, the mQTLs might impair the power of epigenetic-based models of smoking exposure to a certain extent. In addition, such genetic variants could be the key factor to distinguish between the heritable and smoking-induced impact on epigenome disparities. These mQTLs are of special importance when DNA methylation markers measured by Illumina Infinium assay are used for any comparative population studies related to smoking-related cancers and chronic diseases.

  5. Quantitative high-resolution sensing of DNA hybridization using magnetic tweezers with evanescent illumination

    Science.gov (United States)

    Oliver, Piercen M.; Park, Jin Seon; Vezenov, Dmitri

    2011-02-01

    We applied the combined approach of evanescent nanometry and force spectroscopy using magnetic tweezers to quantify the degree of hybridization of a single synthetic single-stranded DNA oligomer to a resolution approaching a single-base. In this setup, the 200 nucleotide long DNA was covalently attached to the surface of an optically transparent solid support at one end and to the surface of a superparamagnetic fluorescent microsphere (force probe) at the other end. The force was applied to the probes using an electromagnet. The end-to-end molecular distance (i.e. out-of-image-plane position of the force probe) was determined from the intensity of the probe fluorescence image observed with total-internal reflectance microscopy. An equation of state for single stranded DNA molecules under tension (extensible freely jointed chain) was used to derive the penetration depth of the evanescent field and to calibrate the magnetic properties of the force probes. The parameters of the magnetic response of the force probes obtained from the equation of state remained constant when changing the penetration depth, indicating a robust calibration procedure. The results of such a calibration were also confirmed using independently measured probe-surface distances for probes mounted onto cantilevers of an atomic force microscope. Upon hybridization of the complementary 50 nucleotide-long oligomer to the surface-bound 200-mer, the changes in the force-distance curves were consistent with the quantitative conversion of 25% of the original single-stranded DNA to its double-stranded form, which was modeled as an elastic rod. The method presented here for quantifying the hybridization state of the single DNA molecules has potential for determining the degree of hybridization of individual molecules in a single molecule array with high accuracy.We applied the combined approach of evanescent nanometry and force spectroscopy using magnetic tweezers to quantify the degree of hybridization

  6. SMAD3 Is Upregulated in Human Osteoarthritic Cartilage Independent of the Promoter DNA Methylation.

    Science.gov (United States)

    Aref-Eshghi, Erfan; Liu, Ming; Razavi-Lopez, Seyd Babak; Hirasawa, Kensuke; Harper, Patricia E; Martin, Glynn; Furey, Andrew; Green, Roger; Sun, Guang; Rahman, Proton; Zhai, Guangju

    2016-02-01

    To compare SMAD3 gene expression between human osteoarthritic and healthy cartilage and to examine whether expression is regulated by the promoter DNA methylation of the gene. Human cartilage samples were collected from patients undergoing total hip/knee joint replacement surgery due to primary osteoarthritis (OA), and from patients with hip fractures as controls. DNA/RNA was extracted from the cartilage tissues. Real-time quantitative PCR was performed to measure gene expression, and Sequenom EpiTyper was used to assay DNA methylation. Mann-Whitney test was used to compare the methylation and expression levels between OA cases and controls. Spearman rank correlation coefficient was calculated to examine the association between the methylation and gene expression. A total of 58 patients with OA (36 women, 22 men; mean age 64 ± 9 yrs) and 55 controls (43 women, 12 men; mean age 79 ± 10 yrs) were studied. SMAD3 expression was on average 83% higher in OA cartilage than in controls (p = 0.0005). No difference was observed for DNA methylation levels in the SMAD3 promoter region between OA cases and controls. No correlation was found between SMAD3 expression and promoter DNA methylation. Our study demonstrates that SMAD3 is significantly overexpressed in OA. This overexpression cannot be explained by DNA methylation in the promoter region. The results suggest that the transforming growth factor-β/SMAD3 pathway may be overactivated in OA cartilage and has potential in developing targeted therapies for OA.

  7. Nonneutral mitochondrial DNA variation in humans and chimpanzees

    Energy Technology Data Exchange (ETDEWEB)

    Nachman, M.W.; Aquadro, C.F. [Cornell Univ., Ithaca, NY (United States); Brown, W.M. [Univ. of Michigan, Ann Arbor, MI (United States)] [and others

    1996-03-01

    We sequenced the NADH dehydrogenase subunit 3 (ND3) gene from a sample of 61 humans, five common chimpanzees, and one gorilla to test whether patterns of mitochondrial DNA (mtDNA) variation are consistent with a neutral model of molecular evolution. Within humans and within chimpanzees, the ratio of replacement to silent nucleotide substitutions was higher than observed in comparisons between species, contrary to neutral expectations. To test the generality of this result, we reanalyzed published human RFLP data from the entire mitochondrial genome. Gains of restriction sites relative to a known human mtDNA sequence were used to infer unambiguous nucleotide substitutions. We also compared the complete mtDNA sequences of three humans. Both the RFLP data and the sequence data reveal a higher ratio of replacement to silent nucleotide substitutions within humans than is seen between species. This pattern is observed at most or all human mitochondrial genes and is inconsistent with a strictly neutral model. These data suggest that many mitochondrial protein polymorphisms are slightly deleterious, consistent with studies of human mitochondrial diseases. 59 refs., 2 figs., 8 tabs.

  8. Quantitative characterization of conformational-specific protein-DNA binding using a dual-spectral interferometric imaging biosensor

    Science.gov (United States)

    Zhang, Xirui; Daaboul, George G.; Spuhler, Philipp S.; Dröge, Peter; Ünlü, M. Selim

    2016-03-01

    DNA-binding proteins play crucial roles in the maintenance and functions of the genome and yet, their specific binding mechanisms are not fully understood. Recently, it was discovered that DNA-binding proteins recognize specific binding sites to carry out their functions through an indirect readout mechanism by recognizing and capturing DNA conformational flexibility and deformation. High-throughput DNA microarray-based methods that provide large-scale protein-DNA binding information have shown effective and comprehensive analysis of protein-DNA binding affinities, but do not provide information of DNA conformational changes in specific protein-DNA complexes. Building on the high-throughput capability of DNA microarrays, we demonstrate a quantitative approach that simultaneously measures the amount of protein binding to DNA and nanometer-scale DNA conformational change induced by protein binding in a microarray format. Both measurements rely on spectral interferometry on a layered substrate using a single optical instrument in two distinct modalities. In the first modality, we quantitate the amount of binding of protein to surface-immobilized DNA in each DNA spot using a label-free spectral reflectivity technique that accurately measures the surface densities of protein and DNA accumulated on the substrate. In the second modality, for each DNA spot, we simultaneously measure DNA conformational change using a fluorescence vertical sectioning technique that determines average axial height of fluorophores tagged to specific nucleotides of the surface-immobilized DNA. The approach presented in this paper, when combined with current high-throughput DNA microarray-based technologies, has the potential to serve as a rapid and simple method for quantitative and large-scale characterization of conformational specific protein-DNA interactions.DNA-binding proteins play crucial roles in the maintenance and functions of the genome and yet, their specific binding mechanisms are

  9. Serial Quantitative PCR Assay for Detection, Species Discrimination, and Quantification of Leishmania spp. in Human Samples▿

    Science.gov (United States)

    Weirather, Jason L.; Jeronimo, Selma M. B.; Gautam, Shalini; Sundar, Shyam; Kang, Mitchell; Kurtz, Melissa A.; Haque, Rashidul; Schriefer, Albert; Talhari, Sinésio; Carvalho, Edgar M.; Donelson, John E.; Wilson, Mary E.

    2011-01-01

    The Leishmania species cause a variety of human disease syndromes. Methods for diagnosis and species differentiation are insensitive and many require invasive sampling. Although quantitative PCR (qPCR) methods are reported for leishmania detection, no systematic method to quantify parasites and determine the species in clinical specimens is established. We developed a serial qPCR strategy to identify and rapidly differentiate Leishmania species and quantify parasites in clinical or environmental specimens. SYBR green qPCR is mainly employed, with corresponding TaqMan assays for validation. The screening primers recognize kinetoplast minicircle DNA of all Leishmania species. Species identification employs further qPCR set(s) individualized for geographic regions, combining species-discriminating probes with melt curve analysis. The assay was sufficient to detect Leishmania parasites, make species determinations, and quantify Leishmania spp. in sera, cutaneous biopsy specimens, or cultured isolates from subjects from Bangladesh or Brazil with different forms of leishmaniasis. The multicopy kinetoplast DNA (kDNA) probes were the most sensitive and useful for quantification based on promastigote standard curves. To test their validity for quantification, kDNA copy numbers were compared between Leishmania species, isolates, and life stages using qPCR. Maxicircle and minicircle copy numbers differed up to 6-fold between Leishmania species, but the differences were smaller between strains of the same species. Amastigote and promastigote leishmania life stages retained similar numbers of kDNA maxi- or minicircles. Thus, serial qPCR is useful for leishmania detection and species determination and for absolute quantification when compared to a standard curve from the same Leishmania species. PMID:22042830

  10. Detection of Leishmania infantum DNA in conjunctival swabs of cats by quantitative real-time PCR.

    Science.gov (United States)

    Benassi, Julia Cristina; Benvenga, Graziella U; Ferreira, Helena Lage; Pereira, Vanessa F; Keid, Lara B; Soares, Rodrigo; Oliveira, Tricia Maria Ferreira de Sousa

    2017-06-01

    Although some studies have investigated the potential role of cats as a reservoir for Leishmania, their role in the epidemiology of visceral leishmaniasis (VL) is still poorly understood. Molecular diagnostic techniques are an important tool in VL diagnosis, and PCR shows high sensitivity and specificity for Leishmania spp. detection. Quantitative real-time PCR (qPCR) is a method that permits quantitative analysis of a large number of samples, resulting in more sensitive, accurate, and reproducible measurements of specific DNA present in the sample. This study compared real-time PCR (qPCR) and conventional PCR (cPCR) for detection of Leishmania spp. in blood and conjunctival swab (CS) samples of healthy cats from a non-endemic area in the state of São Paulo, Brazil. Of all CS samples, 1.85% (2/108) were positive for Leishmania spp. by both cPCR as qPCR (kappa index = 1), indicating excellent agreement between the two methods. The DNA from the two CS-cPCR- and CS-qPCR-positive samples was further tested with a PCR test amplifying the Leishmania spp. discriminative rRNA internal transcribed spacer 1 (ITS 1), of which one sample generated a 300-350-bp DNA fragment whose size varies according to the Leishmania species. Following sequencing, the fragment showed 100% similarity to a GenBank L. infantum sequence obtained from a cat in Italy. In conclusion, the association of qPCR and CS proved to be effective for detection of Leishmania in cats. Conjunctival swab samples were shown to be a practical and better alternative to blood samples and may be useful in the diagnosis and studies of feline leishmaniasis. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. D-ribose inhibits DNA repair synthesis in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Zunica, G.; Marini, M.; Brunelli, M.A.; Chiricolo, M.; Franceschi, C.

    1986-07-31

    D-ribose is cytotoxic for quiescent human lymphocytes and severely inhibits their PHA-induced proliferation at concentrations (25-50 mM) at which other simple sugars are ineffective. In order to explain these effects, DNA repair synthesis was evaluated in PHA-stimulated human lymphocytes treated with hydroxyurea and irradiated. D-ribose, in contrast to other reducing sugars, did not induce repair synthesis and therefore did not apparently damage DNA in a direct way, although it markedly inhibited gamma ray-induced repair. Taking into account that lymphocytes must rejoin physiologically-formed DNA strand breaks in order to enter the cell cycle, we suggest that D-ribose exerts its cytotoxic activity by interfering with metabolic pathways critical for the repair of DNA breaks.

  12. Improved methods for capture, extraction, and quantitative assay of environmental DNA from Asian bigheaded carp (Hypophthalmichthys spp..

    Directory of Open Access Journals (Sweden)

    Cameron R Turner

    Full Text Available Indirect, non-invasive detection of rare aquatic macrofauna using aqueous environmental DNA (eDNA is a relatively new approach to population and biodiversity monitoring. As such, the sensitivity of monitoring results to different methods of eDNA capture, extraction, and detection is being investigated in many ecosystems and species. One of the first and largest conservation programs with eDNA-based monitoring as a central instrument focuses on Asian bigheaded carp (Hypophthalmichthys spp., an invasive fish spreading toward the Laurentian Great Lakes. However, the standard eDNA methods of this program have not advanced since their development in 2010. We developed new, quantitative, and more cost-effective methods and tested them against the standard protocols. In laboratory testing, our new quantitative PCR (qPCR assay for bigheaded carp eDNA was one to two orders of magnitude more sensitive than the existing endpoint PCR assays. When applied to eDNA samples from an experimental pond containing bigheaded carp, the qPCR assay produced a detection probability of 94.8% compared to 4.2% for the endpoint PCR assays. Also, the eDNA capture and extraction method we adapted from aquatic microbiology yielded five times more bigheaded carp eDNA from the experimental pond than the standard method, at a per sample cost over forty times lower. Our new, more sensitive assay provides a quantitative tool for eDNA-based monitoring of bigheaded carp, and the higher-yielding eDNA capture and extraction method we describe can be used for eDNA-based monitoring of any aquatic species.

  13. Preclinical pharmacokinetics and biodistribution of human papillomavirus DNA vaccine delivered in human endogenous retrovirus envelope-coated baculovirus vector.

    Science.gov (United States)

    Cho, Hee-Jeong; Lee, Soondong; Im, Saewon; Kim, Mi-Gyeong; Lee, Jaewoo; Lee, Hee-Jung; Lee, Keyong Ho; Kim, Sujeong; Kim, Young Bong; Oh, Yu-Kyoung

    2012-02-01

    Test pharmacokinetics and biodistribution of a human papillomavirus(HPV)16L1 DNA vaccine delivered in human endogenous retrovirus envelope protein (HERV)-expressing baculovirus (AcHERV) and those of naked plasmid vaccine. HPV16L1 gene was administrated as a naked plasmid or in AcHERV to mice via intravenous and intramuscular routes. HPV16L1 gene was extracted and assayed by quantitative real-time polymerase chain reaction, which was determined to have a detection limit of 50 copies/µg genomic DNA.. Mean residence times of HPV16L1 in AcHERV were 4.8- and 272.2-fold higher than naked HPV16L1 DNA vaccines after intramuscular and intravenous administration, respectively. Naked HPV16L1 DNA levels 1 month after injection were >3 orders of magnitude lower in each tissue tested than AcHERV-delivered HPV16L1, which was retained in most tissues without specific tissue tropism. AcHERV-delivered HPV16L1 administered intramuscularly persisted at the injection sites. However, the levels of copy numbers in muscle were low (1,800/μg genomic DNA) after 1 month, and undetectable after 6 months. HPV16L1 delivered via AcHERV resides longer in the body than HPV16L1 in naked form. The lack of tissue tropism ensures the safety of AcHERV vectors for further development.

  14. Bayesian analysis of high-throughput quantitative measurement of protein-DNA interactions.

    Directory of Open Access Journals (Sweden)

    David D Pollock

    Full Text Available Transcriptional regulation depends upon the binding of transcription factor (TF proteins to DNA in a sequence-dependent manner. Although many experimental methods address the interaction between DNA and proteins, they generally do not comprehensively and accurately assess the full binding repertoire (the complete set of sequences that might be bound with at least moderate strength. Here, we develop and evaluate through simulation an experimental approach that allows simultaneous high-throughput quantitative analysis of TF binding affinity to thousands of potential DNA ligands. Tens of thousands of putative binding targets can be mixed with a TF, and both the pre-bound and bound target pools sequenced. A hierarchical Bayesian Markov chain Monte Carlo approach determines posterior estimates for the dissociation constants, sequence-specific binding energies, and free TF concentrations. A unique feature of our approach is that dissociation constants are jointly estimated from their inferred degree of binding and from a model of binding energetics, depending on how many sequence reads are available and the explanatory power of the energy model. Careful experimental design is necessary to obtain accurate results over a wide range of dissociation constants. This approach, which we call Simultaneous Ultra high-throughput Ligand Dissociation EXperiment (SULDEX, is theoretically capable of rapid and accurate elucidation of an entire TF-binding repertoire.

  15. A quantitative transcriptome reference map of the normal human hippocampus.

    Science.gov (United States)

    Caracausi, Maria; Rigon, Vania; Piovesan, Allison; Strippoli, Pierluigi; Vitale, Lorenza; Pelleri, Maria Chiara

    2016-01-01

    We performed an innovative systematic meta-analysis of 41 gene expression profiles of normal human hippocampus to provide a quantitative transcriptome reference map of it, i.e. a reference typical value of expression for each of the 30,739 known mapped and the 16,258 uncharacterized (unmapped) transcripts. For this aim, we used the software called TRAM (Transcriptome Mapper), which is able to generate transcriptome maps based on gene expression data from multiple sources. We also analyzed differential expression by comparing the hippocampus with the whole brain transcriptome map to identify a typical expression pattern of this subregion compared with the whole organ. Finally, due to the fact that the hippocampus is one of the main brain region to be severely affected in trisomy 21 (the best known genetic cause of intellectual disability), a particular attention was paid to the expression of chromosome 21 (chr21) genes. Data were downloaded from microarray databases, processed, and analyzed using TRAM software. Among the main findings, the most over-expressed loci in the hippocampus are the expressed sequence tag cluster Hs.732685 and the member of the calmodulin gene family CALM2. The tubulin folding cofactor B (TBCB) gene is the best gene at behaving like a housekeeping gene. The hippocampus vs. the whole brain differential transcriptome map shows the over-expression of LINC00114, a long non-coding RNA mapped on chr21. The hippocampus transcriptome map was validated in vitro by assaying gene expression through several magnitude orders by "Real-Time" reverse transcription polymerase chain reaction (RT-PCR). The highly significant agreement between in silico and experimental data suggested that our transcriptome map may be a useful quantitative reference benchmark for gene expression studies related to human hippocampus. Furthermore, our analysis yielded biological insights about those genes that have an intrinsic over-/under-expression in the hippocampus. © 2015

  16. Islet expression of the DNA repair enzyme 8-oxoguanosine DNA glycosylase (Ogg1 in human type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Yoon Kun-Ho

    2002-04-01

    Full Text Available Abstract Background It has become increasingly clear that β-cell failure plays a critical role in the pathogenesis of type 2 diabetes. Free-radical mediated β-cell damage has been intensively studied in type 1 diabetes, but not in human type 2 diabetes. Therefore, we studied the protein expression of the DNA repair enzyme Ogg1 in pancreases from type 2 diabetics. Ogg1 was studied because it is the major enzyme involved in repairing 7,8-dihydro-8-oxoguanosine DNA adducts, a lesion previously observed in a rat model of type 2 diabetes. Moreover, in a gene expression screen, Ogg1 was over-expressed in islets from a human type 2 diabetic. Methods Immunofluorescent staining of Ogg1 was performed on pancreatic specimens from healthy controls and patients with diabetes for 2–23 years. The intensity and islet area stained for Ogg1 was evaluated by semi-quantitative scoring. Results Both the intensity and the area of islet Ogg1 staining were significantly increased in islets from the type 2 diabetic subjects compared to the healthy controls. A correlation between increased Ogg1 fluorescent staining intensity and duration of diabetes was also found. Most of the staining observed was cytoplasmic, suggesting that mitochondrial Ogg1 accounts primarily for the increased Ogg1 expression. Conclusion We conclude that oxidative stress related DNA damage may be a novel important factor in the pathogenesis of human type 2 diabetes. An increase of Ogg1 in islet cell mitochondria is consistent with a model in which hyperglycemia and consequent increased β-cell oxidative metabolism lead to DNA damage and the induction of Ogg1 expression.

  17. False-positive Human Papillomavirus DNA tests in cervical screening

    DEFF Research Database (Denmark)

    Rebolj, Matejka; Pribac, Igor; Lynge, Elsebeth

    2011-01-01

    Based on data from randomised controlled trials (RCT) on primary cervical screening, it has been reported that the problem of more frequent false-positive tests in Human Papillomavirus (HPV) DNA screening compared to cytology could be overcome. However, these reports predominantly operated with a...... with a narrow definition of a (false-)positive test. The aim of this paper was to illustrate how the narrow definition affected the measured adverse effects of HPV DNA screening compared with cytology screening....

  18. Quantitation of 7-ethylguanine in leukocyte DNA from smokers and nonsmokers by liquid chromatography-nanoelectrospray-high resolution tandem mass spectrometry.

    Science.gov (United States)

    Balbo, Silvia; Villalta, Peter W; Hecht, Stephen S

    2011-10-17

    There is considerable evidence for the exposure of humans to an unknown ethylating agent, and some studies indicate that cigarette smoking may be one source of this exposure. Therefore, we have developed a liquid chromatography-nanoelectrospray-high resolution tandem mass spectrometry-selected reaction monitoring (LC-NSI-HRMS/MS-SRM) method for the analysis of 7-ethyl-Gua in human leukocyte DNA, a readily available source of DNA. [(15)N(5)]7-Ethyl-Gua was used as the internal standard. Leukocyte DNA was isolated and treated by thermal neutral hydrolysis. The hydrolysate was partially purified by solid-phase extraction. The fraction containing 7-ethyl-Gua was analyzed by LC-NSI-HRMS/MS-SRM using the transition m/z 180 [M + H](+)→ m/z 152.05669 [Gua + H](+) for 7-ethyl-Gua and m/z 185 → m/z 157.04187 for the internal standard. The detection limit was approximately 10 amol on column, while the limit of quantitation was about 8 fmol/μmol Gua starting with 180 μg DNA (corresponding to 36 μg DNA on-column). Leukocyte DNA samples from 30 smokers and 30 nonsmokers were analyzed. Clear peaks for 7-ethyl-Gua and the internal standard were observed in most of the samples. The mean (±SD) level of 7-ethyl-Gua measured in leukocyte DNA from smokers was 49.6 ± 43.3 (range 14.6-181) fmol/μmol Gua, while that from nonsmokers was 41.3 ± 34.9 (range 9.64-157) fmol/μmol Gua. Although a significant difference between smokers and nonsmokers was not observed, the method described here is unique in the use of high resolution mass spectrometry and establishes for the first time the presence of 7-ethyl-Gua in human leukocyte DNA.

  19. Detection of Streptococcus mutans Genomic DNA in Human DNA Samples Extracted from Saliva and Blood

    Science.gov (United States)

    Vieira, Alexandre R.; Deeley, Kathleen B.; Callahan, Nicholas F.; Noel, Jacqueline B.; Anjomshoaa, Ida; Carricato, Wendy M.; Schulhof, Louise P.; DeSensi, Rebecca S.; Gandhi, Pooja; Resick, Judith M.; Brandon, Carla A.; Rozhon, Christopher; Patir, Asli; Yildirim, Mine; Poletta, Fernando A.; Mereb, Juan C.; Letra, Ariadne; Menezes, Renato; Wendell, Steven; Lopez-Camelo, Jorge S.; Castilla, Eduardo E.; Orioli, Iêda M.; Seymen, Figen; Weyant, Robert J.; Crout, Richard; McNeil, Daniel W.; Modesto, Adriana; Marazita, Mary L.

    2011-01-01

    Caries is a multifactorial disease, and studies aiming to unravel the factors modulating its etiology must consider all known predisposing factors. One major factor is bacterial colonization, and Streptococcus mutans is the main microorganism associated with the initiation of the disease. In our studies, we have access to DNA samples extracted from human saliva and blood. In this report, we tested a real-time PCR assay developed to detect copies of genomic DNA from Streptococcus mutans in 1,424 DNA samples from humans. Our results suggest that we can determine the presence of genomic DNA copies of Streptococcus mutans in both DNA samples from caries-free and caries-affected individuals. However, we were not able to detect the presence of genomic DNA copies of Streptococcus mutans in any DNA samples extracted from peripheral blood, which suggests the assay may not be sensitive enough for this goal. Values of the threshold cycle of the real-time PCR reaction correlate with higher levels of caries experience in children, but this correlation could not be detected for adults. PMID:21731912

  20. Caffeine and human DNA metabolism: the magic and the mystery

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, William K.; Heffernan, Timothy P.; Beaulieu, Lea M.; Doherty, Sharon; Frank, Alexandra R.; Zhou Yingchun; Bryant, Miriam F.; Zhou Tong; Luche, Douglas D.; Nikolaishvili-Feinberg, Nana; Simpson, Dennis A.; Cordeiro-Stone, Marila

    2003-11-27

    The ability of caffeine to reverse cell cycle checkpoint function and enhance genotoxicity after DNA damage was examined in telomerase-expressing human fibroblasts. Caffeine reversed the ATM-dependent S and G2 checkpoint responses to DNA damage induced by ionizing radiation (IR), as well as the ATR- and Chk1-dependent S checkpoint response to ultraviolet radiation (UVC). Remarkably, under conditions in which IR-induced G2 delay was reversed by caffeine, IR-induced G1 arrest was not. Incubation in caffeine did not increase the percentage of cells entering the S phase 6-8 h after irradiation; ATM-dependent phosphorylation of p53 and transactivation of p21{sup Cip1/Waf1} post-IR were resistant to caffeine. Caffeine alone induced a concentration- and time-dependent inhibition of DNA synthesis. It inhibited the entry of human fibroblasts into S phase by 70-80% regardless of the presence or absence of wildtype ATM or p53. Caffeine also enhanced the inhibition of cell proliferation induced by UVC in XP variant fibroblasts. This effect was reversed by expression of DNA polymerase {eta}, indicating that translesion synthesis of UVC-induced pyrimidine dimers by DNA pol {eta} protects human fibroblasts against UVC genotoxic effects even when other DNA repair functions are compromised by caffeine.

  1. Low-Dose Formaldehyde Delays DNA Damage Recognition and DNA Excision Repair in Human Cells

    Science.gov (United States)

    Luch, Andreas; Frey, Flurina C. Clement; Meier, Regula; Fei, Jia; Naegeli, Hanspeter

    2014-01-01

    Objective Formaldehyde is still widely employed as a universal crosslinking agent, preservative and disinfectant, despite its proven carcinogenicity in occupationally exposed workers. Therefore, it is of paramount importance to understand the possible impact of low-dose formaldehyde exposures in the general population. Due to the concomitant occurrence of multiple indoor and outdoor toxicants, we tested how formaldehyde, at micromolar concentrations, interferes with general DNA damage recognition and excision processes that remove some of the most frequently inflicted DNA lesions. Methodology/Principal Findings The overall mobility of the DNA damage sensors UV-DDB (ultraviolet-damaged DNA-binding) and XPC (xeroderma pigmentosum group C) was analyzed by assessing real-time protein dynamics in the nucleus of cultured human cells exposed to non-cytotoxic (formaldehyde concentrations. The DNA lesion-specific recruitment of these damage sensors was tested by monitoring their accumulation at local irradiation spots. DNA repair activity was determined in host-cell reactivation assays and, more directly, by measuring the excision of DNA lesions from chromosomes. Taken together, these assays demonstrated that formaldehyde obstructs the rapid nuclear trafficking of DNA damage sensors and, consequently, slows down their relocation to DNA damage sites thus delaying the excision repair of target lesions. A concentration-dependent effect relationship established a threshold concentration of as low as 25 micromolar for the inhibition of DNA excision repair. Conclusions/Significance A main implication of the retarded repair activity is that low-dose formaldehyde may exert an adjuvant role in carcinogenesis by impeding the excision of multiple mutagenic base lesions. In view of this generally disruptive effect on DNA repair, we propose that formaldehyde exposures in the general population should be further decreased to help reducing cancer risks. PMID:24722772

  2. Heteroplasmy of the human mtDNA control region remains constant during life.

    Science.gov (United States)

    Lagerström-Fermér, M; Olsson, C; Forsgren, L; Syvänen, A C

    2001-05-01

    In a longitudinal, retrospective study, we monitored the level of heteroplasmy at nucleotide position (nt) 309 and nt 16189 of the control region of human mtDNA. As a unique source of DNA, we analyzed multiple cervical-cell samples collected, during 1 or 2 decades, from four women with heteroplasmy at either nt 309 or nt 16189. According to accurate, quantitative analysis by solid-phase minisequencing, the level of heteroplasmy remained stable in the cervical-cell samples from all four women during the time studied. We also analyzed autopsy samples from several different tissues, all containing nt 309 in heteroplasmic form, of one of the women, who was deceased. On the basis of our results, heteroplasmy in the control region of mtDNA seems to be inherited and is not the result of somatic age-related accumulation.

  3. The human DNA-activated protein kinase, DNA-PK: Substrate specificity

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, C.W.; Connelly, M.A.; Zhang, H.; Sipley, J.A. [Brookhaven National Lab., Upton, NY (United States). Biology Dept.; Lees-Miller, S.P.; Lintott, L.G. [Univ. of Calgary, Alberta (Canada). Dept. of Biological Sciences; Sakaguchi, Kazuyasu; Appella, E. [National Institutes of Health, Bethesda, MD (United States). Lab. of Cell Biology

    1994-11-05

    Although much has been learned about the structure and function of p53 and the probable sequence of subsequent events that lead to cell cycle arrest, little is known about how DNA damage is detected and the nature of the signal that is generated by DNA damage. Circumstantial evidence suggests that protein kinases may be involved. In vitro, human DNA-PK phosphorylates a variety of nuclear DNA-binding, regulatory proteins including the tumor suppressor protein p53, the single-stranded DNA binding protein RPA, the heat shock protein hsp90, the large tumor antigen (TAg) of simian virus 40, a variety of transcription factors including Fos, Jun, serum response factor (SRF), Myc, Sp1, Oct-1, TFIID, E2F, the estrogen receptor, and the large subunit of RNA polymerase II (reviewed in Anderson, 1993; Jackson et al., 1993). However, for most of these proteins, the sites that are phosphorylated by DNA-PK are not known. To determine if the sites that were phosphorylated in vitro also were phosphorylated in vivo and if DNA-PK recognized a preferred protein sequence, the authors identified the sites phosphorylated by DNA-PK in several substrates by direct protein sequence analysis. Each phosphorylated serine or threonine is followed immediately by glutamine in the polypeptide chain; at no other positions are the amino acid residues obviously constrained.

  4. Detection limits of quantitative and digital PCR assays and their influence in presence-absence surveys of environmental DNA

    Science.gov (United States)

    Hunter, Margaret; Dorazio, Robert M.; Butterfield, John S.; Meigs-Friend, Gaia; Nico, Leo; Ferrante, Jason A.

    2017-01-01

    A set of universal guidelines is needed to determine the limit of detection (LOD) in PCR-based analyses of low concentration DNA. In particular, environmental DNA (eDNA) studies require sensitive and reliable methods to detect rare and cryptic species through shed genetic material in environmental samples. Current strategies for assessing detection limits of eDNA are either too stringent or subjective, possibly resulting in biased estimates of species’ presence. Here, a conservative LOD analysis grounded in analytical chemistry is proposed to correct for overestimated DNA concentrations predominantly caused by the concentration plateau, a nonlinear relationship between expected and measured DNA concentrations. We have used statistical criteria to establish formal mathematical models for both quantitative and droplet digital PCR. To assess the method, a new Grass Carp (Ctenopharyngodon idella) TaqMan assay was developed and tested on both PCR platforms using eDNA in water samples. The LOD adjustment reduced Grass Carp occupancy and detection estimates while increasing uncertainty – indicating that caution needs to be applied to eDNA data without LOD correction. Compared to quantitative PCR, digital PCR had higher occurrence estimates due to increased sensitivity and dilution of inhibitors at low concentrations. Without accurate LOD correction, species occurrence and detection probabilities based on eDNA estimates are prone to a source of bias that cannot be reduced by an increase in sample size or PCR replicates. Other applications also could benefit from a standardized LOD such as GMO food analysis, and forensic and clinical diagnostics.

  5. Quantitative Analysis of the DNA Methylation Sensitivity of Transcription Factor Complexes

    Directory of Open Access Journals (Sweden)

    Judith F. Kribelbauer

    2017-06-01

    Full Text Available Although DNA modifications play an important role in gene regulation, the underlying mechanisms remain elusive. We developed EpiSELEX-seq to probe the sensitivity of transcription factor binding to DNA modification in vitro using massively parallel sequencing. Feature-based modeling quantifies the effect of cytosine methylation (5mC on binding free energy in a position-specific manner. Application to the human bZIP proteins ATF4 and C/EBPβ and three different Pbx-Hox complexes shows that 5mCpG can both increase and decrease affinity, depending on where the modification occurs within the protein-DNA interface. The TF paralogs tested vary in their methylation sensitivity, for which we provide a structural rationale. We show that 5mCpG can also enhance in vitro p53 binding and provide evidence for increased in vivo p53 occupancy at methylated binding sites, correlating with primed enhancer histone marks. Our results establish a powerful strategy for dissecting the epigenomic modulation of protein-DNA interactions and their role in gene regulation.

  6. Quantitative photoacoustic elastography of Young's modulus in humans

    Science.gov (United States)

    Hai, Pengfei; Zhou, Yong; Gong, Lei; Wang, Lihong V.

    2017-03-01

    Elastography can noninvasively map the elasticity distribution of biological tissue, which is often altered in pathological states. In this work, we report quantitative photoacoustic elastography (QPAE), capable of measuring Young's modulus of human tissue in vivo. By combining photoacoustic elastography with a stress sensor having known stress-strain behavior, QPAE can simultaneously measure strain and stress, from which Young's modulus is calculated. We first applied QPAE to quantify the Young's modulus of tissue-mimicking agar phantoms with different concentrations. The measured values fitted well with both the empirical expectations based on the agar concentrations and those measured in independent standard compression tests. We then demonstrated the feasibility of QPAE by measuring the Young's modulus of human skeletal muscle in vivo. The data showed a linear relationship between muscle stiffness and loading. The results proved that QPAE can noninvasively quantify the absolute elasticity of biological tissue, thus enabling longitudinal imaging of tissue elasticity. QPAE can be exploited for both preclinical biomechanics studies and clinical applications.

  7. Recombinational DNA repair and human disease

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Larry H.; Schild, David

    2002-11-30

    We review the genes and proteins related to the homologous recombinational repair (HRR) pathway that are implicated in cancer through either genetic disorders that predispose to cancer through chromosome instability or the occurrence of somatic mutations that contribute to carcinogenesis. Ataxia telangiectasia (AT), Nijmegen breakage syndrome (NBS), and an ataxia-like disorder (ATLD), are chromosome instability disorders that are defective in the ataxia telangiectasia mutated (ATM), NBS, and Mre11 genes, respectively. These genes are critical in maintaining cellular resistance to ionizing radiation (IR), which kills largely by the production of double-strand breaks (DSBs). Bloom syndrome involves a defect in the BLM helicase, which seems to play a role in restarting DNA replication forks that are blocked at lesions, thereby promoting chromosome stability. The Werner syndrome gene (WRN) helicase, another member of the RecQ family like BLM, has very recently been found to help mediate homologous recombination. Fanconi anemia (FA) is a genetically complex chromosomal instability disorder involving seven or more genes, one of which is BRCA2. FA may be at least partially caused by the aberrant production of reactive oxidative species. The breast cancer-associated BRCA1 and BRCA2 proteins are strongly implicated in HRR; BRCA2 associates with Rad51 and appears to regulate its activity. We discuss in detail the phenotypes of the various mutant cell lines and the signaling pathways mediated by the ATM kinase. ATM's phosphorylation targets can be grouped into oxidative stress-mediated transcriptional changes, cell cycle checkpoints, and recombinational repair. We present the DNA damage response pathways by using the DSB as the prototype lesion, whose incorrect repair can initiate and augment karyotypic abnormalities.

  8. Mouse DNA contamination in human tissue tested for XMRV

    Directory of Open Access Journals (Sweden)

    Uiprasertkul Mongkol

    2010-12-01

    Full Text Available Abstract Background We used a PCR-based approach to study the prevalence of genetic sequences related to a gammaretrovirus, xenotropic murine leukemia virus-related virus, XMRV, in human prostate cancer. This virus has been identified in the US in prostate cancer patients and in those with chronic fatigue syndrome. However, with the exception of two patients in Germany, XMRV has not been identified in prostate cancer tissue in Europe. Most putative associations of new or old human retroviruses with diseases have turned out to be due to contamination. We have looked for XMRV sequences in DNA extracted from formalin-fixed paraffin- embedded prostate tissues. To control for contamination, PCR assays to detect either mouse mitochondrial DNA (mtDNA or intracisternal A particle (IAP long terminal repeat DNA were run on all samples, owing to their very high copy number in mouse cells. Results In general agreement with the US prevalence, XMRV-like sequences were found in 4.8% of prostate cancers. However, these were also positive, as were 21.5% of XMRV-negative cases, for IAP sequences, and many, but not all were positive for mtDNA sequences. Conclusions These results show that contamination with mouse DNA is widespread and detectable by the highly sensitive IAP assay, but not always with less sensitive assays, such as murine mtDNA PCR. This study highlights the ubiquitous presence of mouse DNA in laboratory specimens and offers a means of rigorous validation for future studies of murine retroviruses in human disease.

  9. Inaccurate DNA synthesis in cell extracts of yeast producing active human DNA polymerase iota.

    Directory of Open Access Journals (Sweden)

    Alena V Makarova

    Full Text Available Mammalian Pol ι has an unusual combination of properties: it is stimulated by Mn(2+ ions, can bypass some DNA lesions and misincorporates "G" opposite template "T" more frequently than incorporates the correct "A." We recently proposed a method of detection of Pol ι activity in animal cell extracts, based on primer extension opposite the template T with a high concentration of only two nucleotides, dGTP and dATP (incorporation of "G" versus "A" method of Gening, abbreviated as "misGvA". We provide unambiguous proof of the "misGvA" approach concept and extend the applicability of the method for the studies of variants of Pol ι in the yeast model system with different cation cofactors. We produced human Pol ι in baker's yeast, which do not have a POLI ortholog. The "misGvA" activity is absent in cell extracts containing an empty vector, or producing catalytically dead Pol ι, or Pol ι lacking exon 2, but is robust in the strain producing wild-type Pol ι or its catalytic core, or protein with the active center L62I mutant. The signature pattern of primer extension products resulting from inaccurate DNA synthesis by extracts of cells producing either Pol ι or human Pol η is different. The DNA sequence of the template is critical for the detection of the infidelity of DNA synthesis attributed to DNA Pol ι. The primer/template and composition of the exogenous DNA precursor pool can be adapted to monitor replication fidelity in cell extracts expressing various error-prone Pols or mutator variants of accurate Pols. Finally, we demonstrate that the mutation rates in yeast strains producing human DNA Pols ι and η are not elevated over the control strain, despite highly inaccurate DNA synthesis by their extracts.

  10. Distribution patterns of postmortem damage in human mitochondrial DNA

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Willerslev, Eske; Hansen, Anders J

    2002-01-01

    The distribution of postmortem damage in mitochondrial DNA retrieved from 37 ancient human DNA samples was analyzed by cloning and was compared with a selection of published animal data. A relative rate of damage (rho(v)) was calculated for nucleotide positions within the human hypervariable region......, such as MT5, have lower in vivo mutation rates and lower postmortem-damage rates. The postmortem data also identify a possible functional subregion of the HVR1, termed "low-diversity 1," through the lack of sequence damage. The amount of postmortem damage observed in mitochondrial coding regions...

  11. [Method validation according to ISO 15189 and SH GTA 04: application for the extraction of DNA and its quantitative evaluation by a spectrophotometric assay].

    Science.gov (United States)

    Harlé, Alexandre; Lion, Maëva; Husson, Marie; Dubois, Cindy; Merlin, Jean-Louis

    2013-01-01

    According to the French legislation on medical biology (January 16th, 2010), all biological laboratories must be accredited according to ISO 15189 for at least 50% of their activities before the end of 2016. The extraction of DNA from a sample of interest, whether solid or liquid is one of the critical steps in molecular biology and specifically in somatic or constitutional genetic. The extracted DNA must meet a number of criteria such quality and also be in sufficient concentration to allow molecular biology assays such as the detection of somatic mutations. This paper describes the validation of the extraction and purification of DNA using chromatographic column extraction and quantitative determination by spectrophotometric assay, according to ISO 15189 and the accreditation technical guide in Human Health SH-GTA-04.

  12. DNA methylation-based variation between human populations.

    Science.gov (United States)

    Kader, Farzeen; Ghai, Meenu

    2017-02-01

    Several studies have proved that DNA methylation affects regulation of gene expression and development. Epigenome-wide studies have reported variation in methylation patterns between populations, including Caucasians, non-Caucasians (Blacks), Hispanics, Arabs, and numerous populations of the African continent. Not only has DNA methylation differences shown to impact externally visible characteristics, but is also a potential biomarker for underlying racial health disparities between human populations. Ethnicity-related methylation differences set their mark during early embryonic development. Genetic variations, such as single-nucleotide polymorphisms and environmental factors, such as age, dietary folate, socioeconomic status, and smoking, impacts DNA methylation levels, which reciprocally impacts expression of phenotypes. Studies show that it is necessary to address these external influences when attempting to differentiate between populations since the relative impacts of these factors on the human methylome remain uncertain. The present review summarises several reported attempts to establish the contribution of differential DNA methylation to natural human variation, and shows that DNA methylation could represent new opportunities for risk stratification and prevention of several diseases amongst populations world-wide. Variation of methylation patterns between human populations is an exciting prospect which inspires further valuable research to apply the concept in routine medical and forensic casework. However, trans-generational inheritance needs to be quantified to decipher the proportion of variation contributed by DNA methylation. The future holds thorough evaluation of the epigenome to understand quantification, heritability, and the effect of DNA methylation on phenotypes. In addition, methylation profiling of the same ethnic groups across geographical locations will shed light on conserved methylation differences in populations.

  13. Ex vivo quantitative multiparametric MRI mapping of human meniscus degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Nebelung, Sven; Kuhl, Christiane; Truhn, Daniel [Aachen University Hospital, Department of Diagnostic and Interventional Radiology, Aachen (Germany); Tingart, Markus; Jahr, Holger [Aachen University Hospital, Department of Orthopaedics, Aachen (Germany); Pufe, Thomas [RWTH Aachen University, Institute of Anatomy and Cell Biology, Aachen (Germany)

    2016-12-15

    To evaluate the diagnostic performance of T1, T1ρ, T2, T2*, and UTE-T2* (ultrashort-echo time-enhanced T2*) mapping in the refined graduation of human meniscus degeneration with histology serving as standard-of-reference. This IRB-approved intra-individual comparative ex vivo study was performed on 24 lateral meniscus body samples obtained from 24 patients undergoing total knee replacement. Samples were assessed on a 3.0-T MRI scanner using inversion-recovery (T1), spin-lock multi-gradient-echo (T1ρ), multi-spin-echo (T2) and multi-gradient-echo (T2* and UTE-T2*) sequences to determine relaxation times of quantitative MRI (qMRI) parameters. Relaxation times were calculated on the respective maps, averaged to the entire meniscus and to its zones. Histologically, samples were analyzed on a four-point score according to Williams (0-III). QMRI results and Williams (sub)scores were correlated using Spearman's ρ, while Williams grade-dependent differences were assessed using Kruskal-Wallis and Dunn's tests. Sensitivities and specificities in the detection of intact (Williams grade [WG]-0) and severely degenerate meniscus (WG-II-III) were calculated. Except for T2*, significant increases in qMRI parameters with increasing Williams grades were observed. T1, T1ρ, T2, and UTE-T2* exhibited high sensitivity and variable specificity rates. Significant marked-to-strong correlations were observed for these parameters with each other, with histological WGs and the subscores tissue integrity and cellularity. QMRI mapping holds promise in the objective evaluation of human meniscus. Although sufficient discriminatory power of T1, T1ρ, T2, and UTE-T2* was only demonstrated for the histological extremes, these data may aid in the future MRI-based parameterization and quantification of human meniscus degeneration. (orig.)

  14. A colony multiplex quantitative PCR-Based 3S3DBC method and variations of it for screening DNA libraries.

    Directory of Open Access Journals (Sweden)

    Yang An

    Full Text Available A DNA library is a collection of DNA fragments cloned into vectors and stored individually in host cells, and is a valuable resource for molecular cloning, gene physical mapping, and genome sequencing projects. To take the best advantage of a DNA library, a good screening method is needed. After describing pooling strategies and issues that should be considered in DNA library screening, here we report an efficient colony multiplex quantitative PCR-based 3-step, 3-dimension, and binary-code (3S3DBC method we used to screen genes from a planarian genomic DNA fosmid library. This method requires only 3 rounds of PCR reactions and only around 6 hours to distinguish one or more desired clones from a large DNA library. According to the particular situations in different research labs, this method can be further modified and simplified to suit their requirements.

  15. Inferring chronological age from DNA methylation patterns of human teeth.

    Science.gov (United States)

    Giuliani, Cristina; Cilli, Elisabetta; Bacalini, Maria Giulia; Pirazzini, Chiara; Sazzini, Marco; Gruppioni, Giorgio; Franceschi, Claudio; Garagnani, Paolo; Luiselli, Donata

    2016-04-01

    Current methods to determine chronological age from modern and ancient remains rely on both morphological and molecular approaches. However, low accuracy and the lack of standardized protocols make the development of alternative methods for the estimation of individual's age even more urgent for several research fields, such as biological anthropology, biodemography, forensics, evolutionary genetics, and ancient DNA studies. Therefore, the aim of this study is to identify genomic regions whose DNA methylation level correlates with age in modern teeth. We used MALDI-TOF mass spectrometry to analyze DNA methylation levels of specific CpGs located in the ELOVL2, FHL2, and PENK genes. We considered methylation data from cementum, dentin and pulp of 21 modern teeth (from 17 to 77 years old) to construct a mathematical model able to exploit DNA methylation values to predict age of the individuals. The median difference between the real age and that estimated using DNA methylation values is 1.20 years (SD = 1.9) if DNA is recovered from both cementum and pulp of the same modern teeth, 2.25 years (SD = 2.5) if DNA is recovered from dental pulp, 2.45 years (SD = 3.3) if DNA is extracted from cementum and 7.07 years (SD = 7.0) when DNA is recovered from dentin only. We propose for the first time the evaluation of DNA methylation at ELOVL2, FHL2, and PENK genes as a powerful tool to predict age in modern teeth for anthropological applications. Future studies are needed to apply this method also to historical and relatively ancient human teeth. © 2015 Wiley Periodicals, Inc.

  16. Tenacity of exogenous human papillomavirus DNA in sperm washing.

    Science.gov (United States)

    Brossfield, J E; Chan, P J; Patton, W C; King, A

    1999-07-01

    Sperm cells have been shown to take up exogenous DNA readily. The hypothesis was that sperm washing would remove exogenous viral DNA infecting sperm cells. The objective was to compare three types of sperm washing procedures for their capacity to remove exogenous human papillomavirus (HPV) DNA from infected sperm. Prewashed sperm were equally divided and sperm in one portion were exposed to L1 HPV DNA fragments for 30 min at 37 degrees C. Untreated washed sperm served as the control. After transfection, the sperm were washed by either centrifuge, two-layer Isolate colloid wash, or test-yolk buffer procedures. Sperm parameters were measured on a Hamilton Thorn HTM-C analyzer. Sperm DNA were extracted and polymerase chain reaction (PCR) was carried out targeting the L1 consensus gene of HPV and the designated sentinel gene, 17q21 spanning the D17S855 gene. Amplified products were analyzed in 2% agarose gel electrophoresis. PCR analyses detected the consensus L1 HPV gene in sperm after they were processed through either of the three procedures. Controls were negative for the L1 gene. Extracted DNA were verified by PCR amplification of 17q21 spanning the D17S855 gene. Transfected sperm had higher percentages of total motility and progression compared with the control. Centrifuged, washed, transfected sperm exhibited a greater curvilinear velocity and hyperactivation. The data showed that washing would not remove exogenous HPV DNA from sperm cells. The viral DNA was tenaciously bound to the sperm, suggesting an internalization into the sperm. The viral DNA also increased the motility of the sperm by affecting the velocity and progression of the sperm, which suggested either an increase in metabolism, an enhancement of the calcium-regulated motility mechanism, or an artifact of PCR reagents. More studies are needed to elucidate the mechanism of DNA stimulated sperm motility.

  17. The Quantitative LOD Score: Test Statistic and Sample Size for Exclusion and Linkage of Quantitative Traits in Human Sibships

    OpenAIRE

    Page, Grier P.; Amos, Christopher I.; Boerwinkle, Eric

    1998-01-01

    We present a test statistic, the quantitative LOD (QLOD) score, for the testing of both linkage and exclusion of quantitative-trait loci in randomly selected human sibships. As with the traditional LOD score, the boundary values of 3, for linkage, and -2, for exclusion, can be used for the QLOD score. We investigated the sample sizes required for inferring exclusion and linkage, for various combinations of linked genetic variance, total heritability, recombination distance, and sibship size, ...

  18. Highly sensitive fluorescence quantitative detection of specific DNA sequences with molecular beacons and nucleic acid dye SYBR Green I.

    Science.gov (United States)

    Xiang, Dongshan; Zhai, Kun; Xiang, Wenjun; Wang, Lianzhi

    2014-11-01

    A highly sensitive fluorescence method of quantitative detection for specific DNA sequence is developed based on molecular beacon (MB) and nucleic acid dye SYBR Green I by synchronous fluorescence analysis. It is demonstrated by an oligonucleotide sequence of wild-type HBV (target DNA) as a model system. In this strategy, the fluorophore of MB is designed to be 6-carboxyfluorescein group (FAM), and the maximum excitation wavelength and maximum emission wavelength are both very close to that of SYBR Green I. In the presence of targets DNA, the MBs hybridize with the targets DNA and form double-strand DNA (dsDNA), the fluorophore FAM is separated from the quencher BHQ-1, thus the fluorophore emit fluorescence. At the same time, SYBR Green I binds to dsDNA, the fluorescence intensity of SYBR Green I is significantly enhanced. When targets DNA are detected by synchronous fluorescence analysis, the fluorescence peaks of FAM and SYBR Green I overlap completely, so the fluorescence signal of system will be significantly enhanced. Thus, highly sensitive fluorescence quantitative detection for DNA can be realized. Under the optimum conditions, the total fluorescence intensity of FAM and SYBR Green I exhibits good linear dependence on concentration of targets DNA in the range from 2×10(-11) to 2.5×10(-9)M. The detection limit of target DNA is estimated to be 9×10(-12)M (3σ). Compared with previously reported methods of detection DNA with MB, the proposed method can significantly enhance the detection sensitivity. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Field contamination of skeletonized human remains with exogenous DNA.

    Science.gov (United States)

    Edson, Suni M; Christensen, Alexander F

    2013-01-01

    The Armed Forces DNA Identification Laboratory reports the mitochondrial DNA (mtDNA) sequences of over 800 skeletal samples a year for the Joint POW/MIA Accounting Command-Central Identification Laboratory. These sequences are generated from degraded skeletal remains that are presumed to belong to U.S. service members missing from past military conflicts. In the laboratory, it is possible to control for contamination of remains; however, in the field, it can be difficult to prevent modern DNA from being transferred to skeletal elements and being carried forward through the analysis process. Four such cases are described here along with the controls in place in the laboratory to eliminate the possibility of the exogenous DNA being reported as authentic. In each case, the controls implemented by the laboratories prevented the false reporting of contaminant exogenous DNA from remains that were either faunal or human, but lacked endogenous DNA. © 2012 American Academy of Forensic Sciences Published 2012. This article is a U.S. Government work and is in the public domain in the U.S.A.

  20. Quantitative studies of human urinary excretion of uropontin.

    Science.gov (United States)

    Min, W; Shiraga, H; Chalko, C; Goldfarb, S; Krishna, G G; Hoyer, J R

    1998-01-01

    Uropontin is the urinary form of osteopontin, an aspartic acid-rich phosphorylated glycoprotein. Uropontin has been previously shown to be a potent inhibitor of the nucleation, growth and aggregation of calcium oxalate crystals and the binding of these crystals to renal epithelial cells. Quantitative data defining the excretion of this protein are necessary to determine its role in urinary stone formation. In the present studies, we determined uropontin excretion rates of normal humans. Urine samples were obtained under conditions of known dietary intake from young adult human volunteers with no history, radiographic or laboratory evidence of renal disease. Urinary concentrations of uropontin were measured by a sensitive ELISA employing an affinity purified polyclonal antiserum to uropontin. Thirteen normal subjects ingested a constant diet providing 1 gram of calcium, 1 gram of phosphorus, 150 mEq of sodium and 1 gram of protein per kilogram of body wt per day during an eight day study period. The relationship of urinary volume to uropontin excretion was assessed by varying fluid intake on the last four days of the study to change the mean urine volume/24 hr by > 500 ml. Urine collected in six hour aliquots for eight days was analyzed for uropontin by ELISA, and for calcium, and creatinine. Daily uropontin excretion of 13 individual subjects was 3805 +/- 1805 micrograms/24 hr (mean +/- 1 SD). The mean urinary levels (1.9 micrograms/ml) detected in the present study are sufficient for inhibition of crystallization; our previous studies have demonstrated that the nucleation, growth and aggregation of calcium oxalate crystals and their binding to renal cells in vitro are inhibited by this concentration of purified uropontin. In contrast to the regular pattern of diurnal variation of calcium excretion seen in most subjects, uropontin excretion showed no regularity of diurnal variation and was not directly related to either calcium or creatinine excretion or changes in

  1. Genome-Wide Prediction of DNA Methylation Using DNA Composition and Sequence Complexity in Human

    Directory of Open Access Journals (Sweden)

    Chengchao Wu

    2017-02-01

    Full Text Available DNA methylation plays a significant role in transcriptional regulation by repressing activity. Change of the DNA methylation level is an important factor affecting the expression of target genes and downstream phenotypes. Because current experimental technologies can only assay a small proportion of CpG sites in the human genome, it is urgent to develop reliable computational models for predicting genome-wide DNA methylation. Here, we proposed a novel algorithm that accurately extracted sequence complexity features (seven features and developed a support-vector-machine-based prediction model with integration of the reported DNA composition features (trinucleotide frequency and GC content, 65 features by utilizing the methylation profiles of embryonic stem cells in human. The prediction results from 22 human chromosomes with size-varied windows showed that the 600-bp window achieved the best average accuracy of 94.7%. Moreover, comparisons with two existing methods further showed the superiority of our model, and cross-species predictions on mouse data also demonstrated that our model has certain generalization ability. Finally, a statistical test of the experimental data and the predicted data on functional regions annotated by ChromHMM found that six out of 10 regions were consistent, which implies reliable prediction of unassayed CpG sites. Accordingly, we believe that our novel model will be useful and reliable in predicting DNA methylation.

  2. Fast quantitative PCR, locked nucleic acid probes and reduced volume reactions are effective tools for detecting Batrachochytrium dendrobatidis DNA.

    Science.gov (United States)

    Ruthig, Gregory R; Deridder, Benjamin P

    2012-01-24

    The fungal pathogen Batrachochytrium dendrobatidis threatens amphibian populations around the world. The ability to detect this pathogen on infected animals and in the environment is critical for understanding and controlling this pandemic. We tested several advances in quantitative PCR (qPCR) techniques to detect B. dendrobatidis DNA. We used a fast PCR thermocycler and enzymes that reduced the volume and the duration of the reaction. We also compared a conventional TaqMan minor groove binding (MGB) probe to an identical locked nucleic acid (LNA) counterpart. The fast qPCR reaction had a high degree of sensitivity to B. dendrobatidis DNA. The LNA probe was effective for detecting B. dendrobatidis DNA and produced results -similar to those of the MGB probe. The modifications that we tested can improve the cost, time efficiency and specificity of quantitative PCR as a tool for detecting pathogen DNA.

  3. Sulforaphane induces DNA single strand breaks in cultured human cells

    Energy Technology Data Exchange (ETDEWEB)

    Sestili, Piero, E-mail: piero.sestili@uniurb.it [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Paolillo, Marco [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Lenzi, Monia [Dipartimento di Farmacologia, Universita degli Studi di Bologna, Via Irnerio 48, 40126 Bologna (Italy); Colombo, Evelin; Vallorani, Luciana; Casadei, Lucia; Martinelli, Chiara [Dipartimento di Scienze Biomolecolari, Via Maggetti, 21, Universita degli Studi di Urbino ' Carlo Bo' , 61029 Urbino, PU (Italy); Fimognari, Carmela [Dipartimento di Farmacologia, Universita degli Studi di Bologna, Via Irnerio 48, 40126 Bologna (Italy)

    2010-07-07

    Sulforaphane (SFR), an isothiocyanate from cruciferous vegetables, possesses growth-inhibiting and apoptosis-inducing activities in cancer cell lines. Recently, SFR has been shown to promote the mitochondrial formation of reactive oxygen species (ROS) in human cancer cell lines. The present study was undertaken to see whether SFR-derived ROS might cause DNA damage in cultured human cells, namely T limphoblastoid Jurkat and human umbilical vein endothelial cells (HUVEC). 1-3 h treatments with 10-30 {mu}M SFR elicited intracellular ROS formation (as assayed with dihydrorhodamine, DHR, oxidation) as well as DNA breakage (as assessed with fast halo assay, FHA). These effects lacked cell-type specificity, since could be observed in both Jurkat and HUVEC. Differential-pH FHA analysis of damaged DNA showed that SFR causes frank DNA single strand breaks (SSBs); no DNA double strand breaks (DSBs) were found within the considered treatment times (up to 3 h). SFR-derived ROS were formed at the mitochondrial respiratory chain (MRC) level: indeed rotenone or myxothiazol (MRC Complex I and III inhibitors, respectively) abrogated ROS formation. Furthermore ROS were not formed in Jurkat cells pharmacologically depleted of respiring mitochondria (MRC-/Jurkat). Formation of ROS was causally linked to the induction of SSBs: indeed all the experimental conditions capable of preventing ROS formation also prevented the damage of nuclear DNA from SFR-intoxicated cells. As to the toxicological relevance of SSBs, we found that their prevention slightly but significantly attenuated SFR cytotoxicity, suggesting that high-dose SFR toxicity is the result of a complex series of events among which GSH depletion seems to play a pivotal role. In conclusion, the present study identifies a novel mechanism contributing to SFR toxicity which - since DNA damage is a prominent mechanism underlying the cytotoxic activity of established antineoplastic agents - might help to exploit the therapeutic value

  4. The DNA methylome of human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Li, Yingrui; Zhu, Jingde; Tian, Geng

    2010-01-01

    strand), we report a comprehensive (92.62%) methylome and analysis of the unique sequences in human peripheral blood mononuclear cells (PBMC) from the same Asian individual whose genome was deciphered in the YH project. PBMC constitute an important source for clinical blood tests world-wide. We found...... that 68.4% of CpG sites and 80% displayed allele-specific expression (ASE). These data demonstrate that ASM is a recurrent phenomenon and is highly correlated with ASE in human PBMCs. Together with recently reported similar studies, our study provides a comprehensive resource for future epigenomic......DNA methylation plays an important role in biological processes in human health and disease. Recent technological advances allow unbiased whole-genome DNA methylation (methylome) analysis to be carried out on human cells. Using whole-genome bisulfite sequencing at 24.7-fold coverage (12.3-fold per...

  5. Quantitative detection of well-based DNA array using switchable lanthanide luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Karhunen, Ulla, E-mail: umskar@utu.fi [Division of Biotechnology, University of Turku, Tykistökatu 6A, Sixth Floor, FI-20520 Turku (Finland); Soikkeli, Minna; Lahdenperä, Susanne; Soukka, Tero [Division of Biotechnology, University of Turku, Tykistökatu 6A, Sixth Floor, FI-20520 Turku (Finland)

    2013-04-15

    Highlights: ► Oligonucleotide hybridization switches on lanthanide luminescence. ► The binary probe technology enables wash-free nucleic acid array. ► Detection of both synthetic targets and PCR-amplified E. coli DNA is demonstrated. -- Abstract: In this report a novel wash-free method for multiplexed DNA detection is demonstrated employing target specific probe pairs and switchable lanthanide luminescence technology on a solid-phase array. Four oligonucleotide capture probes, conjugated at 3′ to non-luminescent lanthanide ion carrier chelate, were immobilized as a small array on the bottom of a microtiter plate well onto which a mix of corresponding detection probes, conjugated at 5′ to a light absorbing antenna ligand, were added. In the presence of complementary target nucleic acid both the spotted capture probe and the liquid-phase detection probe hybridize adjacently on the target. Consequently the two non-luminescent label molecules self-assemble and form a luminescent mixed lanthanide chelate complex. Lanthanide luminescence is thereafter measured without a wash step from the spots by scanning in time-resolved mode. The homogeneous solid-phase array-based method resulted in quantitative detection of synthetic target oligonucleotides with 0.32 nM and 0.60 nM detection limits in a single target and multiplexed assay, respectively, corresponding to 3× SD of the background. Also qualitative detection of PCR-amplified target from Escherichia coli is described.

  6. Determination of viable wine yeast using DNA binding dyes and quantitative PCR.

    Science.gov (United States)

    Andorrà, Imma; Esteve-Zarzoso, Braulio; Guillamón, José M; Mas, Albert

    2010-12-15

    The detection and quantification of wine yeast can be misleading due to under or overestimation of these microorganisms. Underestimation may be caused by variable growing rates of different microorganisms in culture media or the presence of viable but non-cultivable microorganisms. Overestimation may be caused by the lack of discrimination between live and dead microorganisms if quantitative PCR is used to quantify with DNA as the template. However, culture-independent methods that use dyes have been described to remove the DNA from dead cells and then quantify the live microorganisms. Two dyes have been studied in this paper: ethidium monoazide bromide (EMA) and propidium monoazide bromide (PMA). The technique was applied to grape must fermentation and ageing wines. Both dyes presented similar results on yeast monitoring. Membrane cell recovery was necessary when yeasts were originated from ethanol-containing media. When applied to grape must fermentation, differences of up to 1 log unit were seen between the QPCR estimation with or without the dye during the stationary phase. In ageing wines, good agreement was found between plating techniques and QPCR. Most of the viable cells were also culturable and no differences were observed with the methods, except for Zygosaccharomyces bailii and Dekkera bruxellensis where much higher counts were occasionally detected by QPCR. The presence of excess dead cells did not interfere with the quantification of live cells with either of the dyes. Copyright © 2010 Elsevier B.V. All rights reserved.

  7. The fractal based analysis of human face and DNA variations during aging.

    Science.gov (United States)

    Namazi, Hamidreza; Akrami, Amin; Hussaini, Jamal; Silva, Osmar N; Wong, Albert; Kulish, Vladimir V

    2017-01-16

    Human DNA is the main unit that shapes human characteristics and features such as behavior. Thus, it is expected that changes in DNA (DNA mutation) influence human characteristics and features. Face is one of the human features which is unique and also dependent on his gen. In this paper, for the first time we analyze the variations of human DNA and face simultaneously. We do this job by analyzing the fractal dimension of DNA walk and face during human aging. The results of this study show the human DNA and face get more complex by aging. These complexities are mapped on fractal exponents of DNA walk and human face. The method discussed in this paper can be further developed in order to investigate the direct influence of DNA mutation on the face variations during aging, and accordingly making a model between human face fractality and the complexity of DNA walk.

  8. DNA synthesis in human bone marrow is circadian stage dependent.

    Science.gov (United States)

    Smaaland, R; Laerum, O D; Lote, K; Sletvold, O; Sothern, R B; Bjerknes, R

    1991-06-15

    Fraction of human bone marrow (BM) cells in DNA synthesis has been studied by sampling BM from the sternum or the iliac crests every 4 hours during one 24-hour period in 16 healthy male volunteers. Three of the subjects underwent the sampling procedure twice, resulting in 19 24-hour profiles. The percentage of cells in DNA synthesis measured by flow cytometry demonstrated a large variation along the circadian time scale for each 24-hour profile, with a range of variation from 29% to 339% from lowest to highest value. Seventeen profiles (89.5%) had the highest DNA synthesis during waking hours between 08:00 hours and 20:00 hours, and the lowest percentage of cells in DNA synthesis between 00:00 hours and 04:00 hours. The mean value of the lowest DNA synthesis for each 19 24-hour period was 8.7% +/- 0.6%, while the mean value of the highest DNA synthesis was 17.6% +/- 0.6%, ie, a twofold difference. There was no difference in DNA synthesis between winter and summer. A significantly higher DNA synthesis was demonstrated for samples obtained from sternum as compared with the iliac crests, but the same circadian pattern was demonstrated for both localizations. By taking circadian stage-dependent variations in DNA synthesis into account it may be possible to reduce BM sensitivity to cytotoxic chemotherapy, to increase the effect of hematopoietic growth factors as well as increase the fraction of proliferating cells with careful selection of time of day for harvesting BM cells for auto- or allografting.

  9. The DNA-damage response in human biology and disease

    DEFF Research Database (Denmark)

    Jackson, Stephen P; Bartek, Jiri

    2009-01-01

    , signal its presence and mediate its repair. Such responses, which have an impact on a wide range of cellular events, are biologically significant because they prevent diverse human diseases. Our improving understanding of DNA-damage responses is providing new avenues for disease management....

  10. Ancient DNA in human bone remains from Pompeii archaeological site.

    Science.gov (United States)

    Cipollaro, M; Di Bernardo, G; Galano, G; Galderisi, U; Guarino, F; Angelini, F; Cascino, A

    1998-06-29

    aDNA extraction and amplification procedures have been optimized for Pompeian human bone remains whose diagenesis has been determined by histological analysis. Single copy genes amplification (X and Y amelogenin loci and Y specific alphoid repeat sequences) have been performed and compared with anthropometric data on sexing.

  11. Quantitative analysis of DNA methylation after whole bisulfitome amplification of a minute amount of DNA from body fluids.

    NARCIS (Netherlands)

    Vaissiere, T.; Cuenin, C.; Paliwal, A.; Vineis, P.; Hoek, G.|info:eu-repo/dai/nl/069553475; Krzyzanowski, M.; Airoldi, L.; Dunning, A.; Garte, S.; Malaveille, C.; Overvad, K.; Clavel-Chapelon, F.; Linseisen, J.; Boeing, H.; Trichopoulou, A.; Trichopoulous, D.; Kaladidi, A.; Palli, D.; Krogh, V.; Tumino, R.; Panico, S.; Bueno de Mesquita, H.B.; Peeters, P.H.M.; Kumle, M.; Gonzalez, C.A.; Martinez, C.; Dorronsoro, M.; Barricarte, A.; Navarro, C.; Quiros, J.R.; Berglund, B.; Janzon, L.; Jarvholm, B.; Day, N.E.; Key, T.J.; Saracci, R.; Kaaks, R.; Riboli, E.; Hainaut, P.; Herceg, Z.

    2009-01-01

    Cell-free circulating DNA isolated from the plasma of individuals with cancer has been shown to harbor cancer-associated changes in DNA methylation, and thus it represents an attractive target for biomarker discovery. However, the reliable detection of DNA methylation changes in body fluids has

  12. Quantitative Analysis of Clustered DNA Damages Induced by Silicon Beams of Different Kinetic Energy

    Energy Technology Data Exchange (ETDEWEB)

    Keszenman D. J.; Keszenman, D.J.; Bennett, P.V.; Sutherland, B.M.; Wilson, P.F.

    2013-05-14

    Humans may b exposed to highly energetic charged particle radiation as a result of medical treatments, occupational activitie or accidental events. In recent years, our increasing presence and burgeoning interest in space exploration beyond low Earth orbit has led to a large increase in the research of the biological effects ofcharged particle radiation typical of that encountered in the space radiation environment. The study of the effects of these types of radiation qualities in terms ofDNA damage induction and repair is fundamental to understand mechanisms both underlying their greater biological effectiveness as we)) as the short and long term risks of health effects such as carcinogenesis, degen rative diseases and premature aging. Charged particle radiation induces a variety of DNA alterations, notably bistranded clustered damages, defined as two or more closely-opposed strand break , oxidized bases or abasic sites within a few helical turns. The induction of such highly complex DNA damage enhances the probability of incorrect or incomplete repair and thus constitutes greater potential for genomic instability, cell death and transformation.

  13. NEIL2 protects against oxidative DNA damage induced by sidestream smoke in human cells.

    Directory of Open Access Journals (Sweden)

    Altaf H Sarker

    Full Text Available Secondhand smoke (SHS is a confirmed lung carcinogen that introduces thousands of toxic chemicals into the lungs. SHS contains chemicals that have been implicated in causing oxidative DNA damage in the airway epithelium. Although DNA repair is considered a key defensive mechanism against various environmental attacks, such as cigarette smoking, the associations of individual repair enzymes with susceptibility to lung cancer are largely unknown. This study investigated the role of NEIL2, a DNA glycosylase excising oxidative base lesions, in human lung cells treated with sidestream smoke (SSS, the main component of SHS. To do so, we generated NEIL2 knockdown cells using siRNA-technology and exposed them to SSS-laden medium. Representative SSS chemical compounds in the medium were analyzed by mass spectrometry. An increased production of reactive oxygen species (ROS in SSS-exposed cells was detected through the fluorescent detection and the induction of HIF-1α. The long amplicon-quantitative PCR (LA-QPCR assay detected significant dose-dependent increases of oxidative DNA damage in the HPRT gene of cultured human pulmonary fibroblasts (hPF and BEAS-2B epithelial cells exposed to SSS for 24 h. These data suggest that SSS exposure increased oxidative stress, which could contribute to SSS-mediated toxicity. siRNA knockdown of NEIL2 in hPF and HEK 293 cells exposed to SSS for 24 h resulted in significantly more oxidative DNA damage in HPRT and POLB than in cells with control siRNA. Taken together, our data strongly suggest that decreased repair of oxidative DNA base lesions due to an impaired NEIL2 expression in non-smokers exposed to SSS would lead to accumulation of mutations in genomic DNA of lung cells over time, thus contributing to the onset of SSS-induced lung cancer.

  14. Hairpin structures formed by alpha satellite DNA of human centromeres are cleaved by human topoisomerase IIα

    Science.gov (United States)

    Jonstrup, Anette Thyssen; Thomsen, Tina; Wang, Yong; Knudsen, Birgitta R.; Koch, Jørn; Andersen, Anni H.

    2008-01-01

    Although centromere function has been conserved through evolution, apparently no interspecies consensus DNA sequence exists. Instead, centromere DNA may be interconnected through the formation of certain DNA structures creating topological binding sites for centromeric proteins. DNA topoisomerase II is a protein, which is located at centromeres, and enzymatic topoisomerase II activity correlates with centromere activity in human cells. It is therefore possible that topoisomerase II recognizes and interacts with the alpha satellite DNA of human centromeres through an interaction with potential DNA structures formed solely at active centromeres. In the present study, human topoisomerase IIα-mediated cleavage at centromeric DNA sequences was examined in vitro. The investigation has revealed that the enzyme recognizes and cleaves a specific hairpin structure formed by alpha satellite DNA. The topoisomerase introduces a single-stranded break at the hairpin loop in a reaction, where DNA ligation is partly uncoupled from the cleavage reaction. A mutational analysis has revealed, which features of the hairpin are required for topoisomerease IIα-mediated cleavage. Based on this a model is discussed, where topoisomerase II interacts with two hairpins as a mediator of centromere cohesion. PMID:18824478

  15. DNA Methylation Dynamics of Human Hematopoietic Stem Cell Differentiation.

    Science.gov (United States)

    Farlik, Matthias; Halbritter, Florian; Müller, Fabian; Choudry, Fizzah A; Ebert, Peter; Klughammer, Johanna; Farrow, Samantha; Santoro, Antonella; Ciaurro, Valerio; Mathur, Anthony; Uppal, Rakesh; Stunnenberg, Hendrik G; Ouwehand, Willem H; Laurenti, Elisa; Lengauer, Thomas; Frontini, Mattia; Bock, Christoph

    2016-12-01

    Hematopoietic stem cells give rise to all blood cells in a differentiation process that involves widespread epigenome remodeling. Here we present genome-wide reference maps of the associated DNA methylation dynamics. We used a meta-epigenomic approach that combines DNA methylation profiles across many small pools of cells and performed single-cell methylome sequencing to assess cell-to-cell heterogeneity. The resulting dataset identified characteristic differences between HSCs derived from fetal liver, cord blood, bone marrow, and peripheral blood. We also observed lineage-specific DNA methylation between myeloid and lymphoid progenitors, characterized immature multi-lymphoid progenitors, and detected progressive DNA methylation differences in maturing megakaryocytes. We linked these patterns to gene expression, histone modifications, and chromatin accessibility, and we used machine learning to derive a model of human hematopoietic differentiation directly from DNA methylation data. Our results contribute to a better understanding of human hematopoietic stem cell differentiation and provide a framework for studying blood-linked diseases. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  16. Hypomorphic PCNA mutation underlies a human DNA repair disorder.

    Science.gov (United States)

    Baple, Emma L; Chambers, Helen; Cross, Harold E; Fawcett, Heather; Nakazawa, Yuka; Chioza, Barry A; Harlalka, Gaurav V; Mansour, Sahar; Sreekantan-Nair, Ajith; Patton, Michael A; Muggenthaler, Martina; Rich, Phillip; Wagner, Karin; Coblentz, Roselyn; Stein, Constance K; Last, James I; Taylor, A Malcolm R; Jackson, Andrew P; Ogi, Tomoo; Lehmann, Alan R; Green, Catherine M; Crosby, Andrew H

    2014-07-01

    Numerous human disorders, including Cockayne syndrome, UV-sensitive syndrome, xeroderma pigmentosum, and trichothiodystrophy, result from the mutation of genes encoding molecules important for nucleotide excision repair. Here, we describe a syndrome in which the cardinal clinical features include short stature, hearing loss, premature aging, telangiectasia, neurodegeneration, and photosensitivity, resulting from a homozygous missense (p.Ser228Ile) sequence alteration of the proliferating cell nuclear antigen (PCNA). PCNA is a highly conserved sliding clamp protein essential for DNA replication and repair. Due to this fundamental role, mutations in PCNA that profoundly impair protein function would be incompatible with life. Interestingly, while the p.Ser228Ile alteration appeared to have no effect on protein levels or DNA replication, patient cells exhibited marked abnormalities in response to UV irradiation, displaying substantial reductions in both UV survival and RNA synthesis recovery. The p.Ser228Ile change also profoundly altered PCNA's interaction with Flap endonuclease 1 and DNA Ligase 1, DNA metabolism enzymes. Together, our findings detail a mutation of PCNA in humans associated with a neurodegenerative phenotype, displaying clinical and molecular features common to other DNA repair disorders, which we showed to be attributable to a hypomorphic amino acid alteration.

  17. Structure and mechanism of human DNA polymerase [eta

    Energy Technology Data Exchange (ETDEWEB)

    Biertümpfel, Christian; Zhao, Ye; Kondo, Yuji; Ramón-Maiques, Santiago; Gregory, Mark; Lee, Jae Young; Masutani, Chikahide; Lehmann, Alan R.; Hanaoka, Fumio; Yang, Wei (Sussex); (NIH); (Gakushuin); (Osaka)

    2010-11-03

    The variant form of the human syndrome xeroderma pigmentosum (XPV) is caused by a deficiency in DNA polymerase {eta} (Pol{eta}), a DNA polymerase that enables replication through ultraviolet-induced pyrimidine dimers. Here we report high-resolution crystal structures of human Pol{eta} at four consecutive steps during DNA synthesis through cis-syn cyclobutane thymine dimers. Pol{eta} acts like a 'molecular splint' to stabilize damaged DNA in a normal B-form conformation. An enlarged active site accommodates the thymine dimer with excellent stereochemistry for two-metal ion catalysis. Two residues conserved among Pol{eta} orthologues form specific hydrogen bonds with the lesion and the incoming nucleotide to assist translesion synthesis. On the basis of the structures, eight Pol{eta} missense mutations causing XPV can be rationalized as undermining the molecular splint or perturbing the active-site alignment. The structures also provide an insight into the role of Pol{eta} in replicating through D loop and DNA fragile sites.

  18. Caffeine and human DNA metabolism: the magic and the mystery

    OpenAIRE

    Kaufmann, William K; Heffernan, Timothy P.; Beaulieu, Lea M.; Doherty, Sharon; Frank, Alexandra R.; Zhou, Yingchun; Bryant, Miriam F.; Zhou, Tong; Luche, Douglas D.; Nikolaishvili-Feinberg, Nana; Simpson, Dennis A.; Cordeiro-Stone, Marila

    2003-01-01

    The ability of caffeine to reverse cell cycle checkpoint function and enhance genotoxicity after DNA damage was examined in telomerase-expressing human fibroblasts. Caffeine reversed the ATM-dependent S and G2 checkpoint responses to DNA damage induced by ionizing radiation (IR), as well as the ATR- and Chk1-dependent S checkpoint response to ultraviolet radiation (UVC). Remarkably, under conditions in which IR-induced G2 delay was reversed by caffeine, IR-induced G1 arrest was not. Incubatio...

  19. The proteome of human liver peroxisomes: identification of five new peroxisomal constituents by a label-free quantitative proteomics survey.

    Science.gov (United States)

    Gronemeyer, Thomas; Wiese, Sebastian; Ofman, Rob; Bunse, Christian; Pawlas, Magdalena; Hayen, Heiko; Eisenacher, Martin; Stephan, Christian; Meyer, Helmut E; Waterham, Hans R; Erdmann, Ralf; Wanders, Ronald J; Warscheid, Bettina

    2013-01-01

    The peroxisome is a key organelle of low abundance that fulfils various functions essential for human cell metabolism. Severe genetic diseases in humans are caused by defects in peroxisome biogenesis or deficiencies in the function of single peroxisomal proteins. To improve our knowledge of this important cellular structure, we studied for the first time human liver peroxisomes by quantitative proteomics. Peroxisomes were isolated by differential and Nycodenz density gradient centrifugation. A label-free quantitative study of 314 proteins across the density gradient was accomplished using high resolution mass spectrometry. By pairing statistical data evaluation, cDNA cloning and in vivo colocalization studies, we report the association of five new proteins with human liver peroxisomes. Among these, isochorismatase domain containing 1 protein points to the existence of a new metabolic pathway and hydroxysteroid dehydrogenase like 2 protein is likely involved in the transport or β-oxidation of fatty acids in human peroxisomes. The detection of alcohol dehydrogenase 1A suggests the presence of an alternative alcohol-oxidizing system in hepatic peroxisomes. In addition, lactate dehydrogenase A and malate dehydrogenase 1 partially associate with human liver peroxisomes and enzyme activity profiles support the idea that NAD(+) becomes regenerated during fatty acid β-oxidation by alternative shuttling processes in human peroxisomes involving lactate dehydrogenase and/or malate dehydrogenase. Taken together, our data represent a valuable resource for future studies of peroxisome biochemistry that will advance research of human peroxisomes in health and disease.

  20. The proteome of human liver peroxisomes: identification of five new peroxisomal constituents by a label-free quantitative proteomics survey.

    Directory of Open Access Journals (Sweden)

    Thomas Gronemeyer

    Full Text Available The peroxisome is a key organelle of low abundance that fulfils various functions essential for human cell metabolism. Severe genetic diseases in humans are caused by defects in peroxisome biogenesis or deficiencies in the function of single peroxisomal proteins. To improve our knowledge of this important cellular structure, we studied for the first time human liver peroxisomes by quantitative proteomics. Peroxisomes were isolated by differential and Nycodenz density gradient centrifugation. A label-free quantitative study of 314 proteins across the density gradient was accomplished using high resolution mass spectrometry. By pairing statistical data evaluation, cDNA cloning and in vivo colocalization studies, we report the association of five new proteins with human liver peroxisomes. Among these, isochorismatase domain containing 1 protein points to the existence of a new metabolic pathway and hydroxysteroid dehydrogenase like 2 protein is likely involved in the transport or β-oxidation of fatty acids in human peroxisomes. The detection of alcohol dehydrogenase 1A suggests the presence of an alternative alcohol-oxidizing system in hepatic peroxisomes. In addition, lactate dehydrogenase A and malate dehydrogenase 1 partially associate with human liver peroxisomes and enzyme activity profiles support the idea that NAD(+ becomes regenerated during fatty acid β-oxidation by alternative shuttling processes in human peroxisomes involving lactate dehydrogenase and/or malate dehydrogenase. Taken together, our data represent a valuable resource for future studies of peroxisome biochemistry that will advance research of human peroxisomes in health and disease.

  1. DNA-Based Sensor for Real-Time Measurement of the Enzymatic Activity of Human Topoisomerase I

    DEFF Research Database (Denmark)

    Marcussen, Lærke Bay; Jepsen, Morten Leth; Kristoffersen, Emil Laust

    2013-01-01

    Sensors capable of quantitative real-time measurements may present the easiest and most accurate way to study enzyme activities. Here we present a novel DNA-based sensor for specific and quantitative real-time measurement of the enzymatic activity of the essential human enzyme, topoisomerase I....... The basic design of the sensor relies on two DNA strands that hybridize to form a hairpin structure with a fluorophore-quencher pair. The quencher moiety is released from the sensor upon reaction with human topoisomerase I thus enabling real-time optical measurement of enzymatic activity. The sensor...... is specific for topoisomerase I even in raw cell extracts and presents a simple mean of following enzyme kinetics using standard laboratory equipment such as a qPCR machine or fluorimeter. Human topoisomerase I is a well-known target for the clinically used anti-cancer drugs of the camptothecin family...

  2. Quantitation of varicella-zoster virus DNA in whole blood, plasma, and serum by PCR and electrochemiluminescence

    NARCIS (Netherlands)

    de Jong, M. D.; Weel, J. F.; Schuurman, T.; Wertheim-van Dillen, P. M.; Boom, R.

    2000-01-01

    We describe a highly sensitive assay for quantitation of varicella-zoster virus (VZV) DNA in blood, involving PCR amplification, solution hybridization with Tris-(2, 2'-bipyridine)-ruthenium(II) chelate-labeled probes, and measurement by electrochemiluminescence (ECL). Extraction and amplification

  3. Brief Communication: Quantitative- and molecular-genetic differentiation in humans and chimpanzees: implications for the evolutionary processes underlying cranial diversification.

    Science.gov (United States)

    Weaver, Timothy D

    2014-08-01

    Estimates of the amount of genetic differentiation in humans among major geographic regions (e.g., Eastern Asia vs. Europe) from quantitative-genetic analyses of cranial measurements closely match those from classical- and molecular-genetic markers. Typically, among-region differences account for ∼10% of the total variation. This correspondence is generally interpreted as evidence for the importance of neutral evolutionary processes (e.g., genetic drift) in generating among-region differences in human cranial form, but it was initially surprising because human cranial diversity was frequently assumed to show a strong signature of natural selection. Is the human degree of similarity of cranial and DNA-sequence estimates of among-region genetic differentiation unusual? How do comparisons with other taxa illuminate the evolutionary processes underlying cranial diversification? Chimpanzees provide a useful starting point for placing the human results in a broader comparative context, because common chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) are the extant species most closely related to humans. To address these questions, I used 27 cranial measurements collected on a sample of 861 humans and 263 chimpanzees to estimate the amount of genetic differentiation between pairs of groups (between regions for humans and between species or subspecies for chimpanzees). Consistent with previous results, the human cranial estimates are quite similar to published DNA-sequence estimates. In contrast, the chimpanzee cranial estimates are much smaller than published DNA-sequence estimates. It appears that cranial differentiation has been limited in chimpanzees relative to humans. © 2014 Wiley Periodicals, Inc.

  4. Bi-directional routing of DNA mismatch repair protein human exonuclease 1 to replication foci and DNA double strand breaks

    DEFF Research Database (Denmark)

    Liberti, Sascha E; Andersen, Sofie Dabros; Wang, Jing

    2011-01-01

    Human exonuclease 1 (hEXO1) is implicated in DNA metabolism, including replication, recombination and repair, substantiated by its interactions with PCNA, DNA helicases BLM and WRN, and several DNA mismatch repair (MMR) proteins. We investigated the sub-nuclear localization of hEXO1 during S-phas...

  5. DNA structure in human RNA polymerase II promoters

    DEFF Research Database (Denmark)

    Pedersen, Anders Gorm; Baldi, Pierre; Chauvin, Yves

    1998-01-01

    The fact that DNA three-dimensional structure is important for transcriptional regulation begs the question of whether eukaryotic promoters contain general structural features independently of what genes they control. We present an analysis of a large set of human RNA polymerase II promoters...... with a very low level of sequence similarity. The sequences, which include both TATA-containing and TATA-less promoters, are aligned by hidden Markov models. Using three different models of sequence-derived DNA bendability, the aligned promoters display a common structural profile with bendability being low...... in a region upstream of the transcriptional start point and significantly higher downstream. Investigation of the sequence composition in the two regions shows that the bendability profile originates from the sequential structure of the DNA, rather than the general nucleotide composition...

  6. Preferential access to genetic information from endogenous hominin ancient DNA and accurate quantitative SNP-typing via SPEX

    OpenAIRE

    Brotherton, Paul; Sanchez, Juan J.; Cooper, Alan; Endicott, Phillip

    2009-01-01

    The analysis of targeted genetic loci from ancient, forensic and clinical samples is usually built upon polymerase chain reaction (PCR)-generated sequence data. However, many studies have shown that PCR amplification from poor-quality DNA templates can create sequence artefacts at significant levels. With hominin (human and other hominid) samples, the pervasive presence of highly PCR-amplifiable human DNA contaminants in the vast majority of samples can lead to the creation of recombinant hyb...

  7. Ultrasensitive quantitation of human papillomavirus type 16 E6 oncogene sequences by nested real time PCR

    Directory of Open Access Journals (Sweden)

    López-Revilla Rubén

    2010-05-01

    Full Text Available Abstract Background We have developed an ultrasensitive method based on conventional PCR preamplification followed by nested amplification through real time PCR (qPCR in the presence of the DNA intercalating agent EvaGreen. Results Amplification mixtures calibrated with a known number of pHV101 copies carrying a 645 base pair (bp-long insert of the human papillomavirus type 16 (HPV16 E6 oncogene were used to generate the E6-1 amplicon of 645 bp by conventional PCR and then the E6-2 amplicon of 237 bp by nested qPCR. Direct and nested qPCR mixtures for E6-2 amplification corresponding to 2.5 × 102-2.5 × 106 initial pHV101 copies had threshold cycle (Ct values in the ranges of 18.7-29.0 and 10.0-25.0, respectively. The Ct of qPCR mixtures prepared with 1/50 volumes of preamplified mixtures containing 50 ng of DNA of the SiHa cell line (derived from an invasive cervical cancer with one HPV16 genome per cell was 19.9. Thermal fluorescence extinction profiles of E6-2 amplicons generated from pHV101 and SiHa DNA were identical, with a peak at 85.5°C. Conclusions Our method based on conventional preamplification for 15 cycles increased 10,750 times the sensitivity of nested qPCR for the quantitation of the E6 viral oncogene and confirmed that the SiHa cell line contains one E6-HPV16 copy per cell.

  8. Detection limits of quantitative and digital PCR assays and their influence in presence-absence surveys of environmental DNA.

    Science.gov (United States)

    Hunter, Margaret E; Dorazio, Robert M; Butterfield, John S S; Meigs-Friend, Gaia; Nico, Leo G; Ferrante, Jason A

    2017-03-01

    A set of universal guidelines is needed to determine the limit of detection (LOD) in PCR-based analyses of low-concentration DNA. In particular, environmental DNA (eDNA) studies require sensitive and reliable methods to detect rare and cryptic species through shed genetic material in environmental samples. Current strategies for assessing detection limits of eDNA are either too stringent or subjective, possibly resulting in biased estimates of species' presence. Here, a conservative LOD analysis grounded in analytical chemistry is proposed to correct for overestimated DNA concentrations predominantly caused by the concentration plateau, a nonlinear relationship between expected and measured DNA concentrations. We have used statistical criteria to establish formal mathematical models for both quantitative and droplet digital PCR. To assess the method, a new Grass Carp (Ctenopharyngodon idella) TaqMan assay was developed and tested on both PCR platforms using eDNA in water samples. The LOD adjustment reduced Grass Carp occupancy and detection estimates while increasing uncertainty-indicating that caution needs to be applied to eDNA data without LOD correction. Compared to quantitative PCR, digital PCR had higher occurrence estimates due to increased sensitivity and dilution of inhibitors at low concentrations. Without accurate LOD correction, species occurrence and detection probabilities based on eDNA estimates are prone to a source of bias that cannot be reduced by an increase in sample size or PCR replicates. Other applications also could benefit from a standardized LOD such as GMO food analysis and forensic and clinical diagnostics. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  9. Human identification and analysis of DNA in bones.

    Science.gov (United States)

    Iwamura, Edna Sadayo Miazato; Soares-Vieira, José Arnaldo; Muñoz, Daniel Romero

    2004-12-01

    The introduction of molecular biology techniques, especially of DNA analysis, for human identification is a recent advance in legal medicine. Substantial effort has continuously been made in an attempt to identify cadavers and human remains after wars, socio-political problems and mass disasters. In addition, because of the social dynamics of large cities, there are always cases of missing people, as well as unidentified cadavers and human remains that are found. In the last few years, there has also been an increase in requests for exhumation of human remains in order to determine genetic relationships in civil suits and court action. The authors provide an extensive review of the literature regarding the use of this new methodology for human identification of ancient or recent bones.

  10. The blood DNA virome in 8,000 humans.

    Directory of Open Access Journals (Sweden)

    Ahmed Moustafa

    2017-03-01

    Full Text Available The characterization of the blood virome is important for the safety of blood-derived transfusion products, and for the identification of emerging pathogens. We explored non-human sequence data from whole-genome sequencing of blood from 8,240 individuals, none of whom were ascertained for any infectious disease. Viral sequences were extracted from the pool of sequence reads that did not map to the human reference genome. Analyses sifted through close to 1 Petabyte of sequence data and performed 0.5 trillion similarity searches. With a lower bound for identification of 2 viral genomes/100,000 cells, we mapped sequences to 94 different viruses, including sequences from 19 human DNA viruses, proviruses and RNA viruses (herpesviruses, anelloviruses, papillomaviruses, three polyomaviruses, adenovirus, HIV, HTLV, hepatitis B, hepatitis C, parvovirus B19, and influenza virus in 42% of the study participants. Of possible relevance to transfusion medicine, we identified Merkel cell polyomavirus in 49 individuals, papillomavirus in blood of 13 individuals, parvovirus B19 in 6 individuals, and the presence of herpesvirus 8 in 3 individuals. The presence of DNA sequences from two RNA viruses was unexpected: Hepatitis C virus is revealing of an integration event, while the influenza virus sequence resulted from immunization with a DNA vaccine. Age, sex and ancestry contributed significantly to the prevalence of infection. The remaining 75 viruses mostly reflect extensive contamination of commercial reagents and from the environment. These technical problems represent a major challenge for the identification of novel human pathogens. Increasing availability of human whole-genome sequences will contribute substantial amounts of data on the composition of the normal and pathogenic human blood virome. Distinguishing contaminants from real human viruses is challenging.

  11. The blood DNA virome in 8,000 humans.

    Science.gov (United States)

    Moustafa, Ahmed; Xie, Chao; Kirkness, Ewen; Biggs, William; Wong, Emily; Turpaz, Yaron; Bloom, Kenneth; Delwart, Eric; Nelson, Karen E; Venter, J Craig; Telenti, Amalio

    2017-03-01

    The characterization of the blood virome is important for the safety of blood-derived transfusion products, and for the identification of emerging pathogens. We explored non-human sequence data from whole-genome sequencing of blood from 8,240 individuals, none of whom were ascertained for any infectious disease. Viral sequences were extracted from the pool of sequence reads that did not map to the human reference genome. Analyses sifted through close to 1 Petabyte of sequence data and performed 0.5 trillion similarity searches. With a lower bound for identification of 2 viral genomes/100,000 cells, we mapped sequences to 94 different viruses, including sequences from 19 human DNA viruses, proviruses and RNA viruses (herpesviruses, anelloviruses, papillomaviruses, three polyomaviruses, adenovirus, HIV, HTLV, hepatitis B, hepatitis C, parvovirus B19, and influenza virus) in 42% of the study participants. Of possible relevance to transfusion medicine, we identified Merkel cell polyomavirus in 49 individuals, papillomavirus in blood of 13 individuals, parvovirus B19 in 6 individuals, and the presence of herpesvirus 8 in 3 individuals. The presence of DNA sequences from two RNA viruses was unexpected: Hepatitis C virus is revealing of an integration event, while the influenza virus sequence resulted from immunization with a DNA vaccine. Age, sex and ancestry contributed significantly to the prevalence of infection. The remaining 75 viruses mostly reflect extensive contamination of commercial reagents and from the environment. These technical problems represent a major challenge for the identification of novel human pathogens. Increasing availability of human whole-genome sequences will contribute substantial amounts of data on the composition of the normal and pathogenic human blood virome. Distinguishing contaminants from real human viruses is challenging.

  12. Androgen receptor function links human sexual dimorphism to DNA methylation.

    Science.gov (United States)

    Ammerpohl, Ole; Bens, Susanne; Appari, Mahesh; Werner, Ralf; Korn, Bernhard; Drop, Stenvert L S; Verheijen, Frans; van der Zwan, Yvonne; Bunch, Trevor; Hughes, Ieuan; Cools, Martine; Riepe, Felix G; Hiort, Olaf; Siebert, Reiner; Holterhus, Paul-Martin

    2013-01-01

    Sex differences are well known to be determinants of development, health and disease. Epigenetic mechanisms are also known to differ between men and women through X-inactivation in females. We hypothesized that epigenetic sex differences may also result from sex hormone functions, in particular from long-lasting androgen programming. We aimed at investigating whether inactivation of the androgen receptor, the key regulator of normal male sex development, is associated with differences of the patterns of DNA methylation marks in genital tissues. To this end, we performed large scale array-based analysis of gene methylation profiles on genomic DNA from labioscrotal skin fibroblasts of 8 males and 26 individuals with androgen insensitivity syndrome (AIS) due to inactivating androgen receptor gene mutations. By this approach we identified differential methylation of 167 CpG loci representing 162 unique human genes. These were significantly enriched for androgen target genes and low CpG content promoter genes. Additional 75 genes showed a significant increase of heterogeneity of methylation in AIS compared to a high homogeneity in normal male controls. Our data show that normal and aberrant androgen receptor function is associated with distinct patterns of DNA-methylation marks in genital tissues. These findings support the concept that transcription factor binding to the DNA has an impact on the shape of the DNA methylome. These data which derived from a rare human model suggest that androgen programming of methylation marks contributes to sexual dimorphism in the human which might have considerable impact on the manifestation of sex-associated phenotypes and diseases.

  13. Androgen receptor function links human sexual dimorphism to DNA methylation.

    Directory of Open Access Journals (Sweden)

    Ole Ammerpohl

    Full Text Available Sex differences are well known to be determinants of development, health and disease. Epigenetic mechanisms are also known to differ between men and women through X-inactivation in females. We hypothesized that epigenetic sex differences may also result from sex hormone functions, in particular from long-lasting androgen programming. We aimed at investigating whether inactivation of the androgen receptor, the key regulator of normal male sex development, is associated with differences of the patterns of DNA methylation marks in genital tissues. To this end, we performed large scale array-based analysis of gene methylation profiles on genomic DNA from labioscrotal skin fibroblasts of 8 males and 26 individuals with androgen insensitivity syndrome (AIS due to inactivating androgen receptor gene mutations. By this approach we identified differential methylation of 167 CpG loci representing 162 unique human genes. These were significantly enriched for androgen target genes and low CpG content promoter genes. Additional 75 genes showed a significant increase of heterogeneity of methylation in AIS compared to a high homogeneity in normal male controls. Our data show that normal and aberrant androgen receptor function is associated with distinct patterns of DNA-methylation marks in genital tissues. These findings support the concept that transcription factor binding to the DNA has an impact on the shape of the DNA methylome. These data which derived from a rare human model suggest that androgen programming of methylation marks contributes to sexual dimorphism in the human which might have considerable impact on the manifestation of sex-associated phenotypes and diseases.

  14. DNA methylation profiling of human chromosomes 6, 20 and 22

    Science.gov (United States)

    Eckhardt, Florian; Lewin, Joern; Cortese, Rene; Rakyan, Vardhman K.; Attwood, John; Burger, Matthias; Burton, John; Cox, Tony V.; Davies, Rob; Down, Thomas A.; Haefliger, Carolina; Horton, Roger; Howe, Kevin; Jackson, David K.; Kunde, Jan; Koenig, Christoph; Liddle, Jennifer; Niblett, David; Otto, Thomas; Pettett, Roger; Seemann, Stefanie; Thompson, Christian; West, Tony; Rogers, Jane; Olek, Alex; Berlin, Kurt; Beck, Stephan

    2011-01-01

    DNA methylation constitutes the most stable type of epigenetic modifications modulating the transcriptional plasticity of mammalian genomes. Using bisulfite DNA sequencing, we report high-resolution methylation reference profiles of human chromosomes 6, 20 and 22, providing a resource of about 1.9 million CpG methylation values derived from 12 different tissues. Analysis of 6 annotation categories, revealed evolutionary conserved regions to be the predominant sites for differential DNA methylation and a core region surrounding the transcriptional start site as informative surrogate for promoter methylation. We find 17% of the 873 analyzed genes differentially methylated in their 5′-untranslated regions (5′-UTR) and about one third of the differentially methylated 5′-UTRs to be inversely correlated with transcription. While our study was controlled for factors reported to affect DNA methylation such as sex and age, we did not find any significant attributable effects. Our data suggest DNA methylation to be ontogenetically more stable than previously thought. PMID:17072317

  15. Recovery of latent fingerprints and DNA on human skin.

    Science.gov (United States)

    Färber, Doris; Seul, Andrea; Weisser, Hans-Joachim; Bohnert, Michael

    2010-11-01

    The project "Latent Fingerprints and DNA on Human Skin" was the first systematic research in Europe dealing with detection of fingerprints and DNA left by offenders on the skin of corpses. One thousand samples gave results that allow general statements on the materials and methods used. The tests were carried out according to a uniform trial structure. Fingerprints were deposited by natural donors on corpses. The latent fingerprints were treated with magnetic powder or black fingerprint powder. Afterward, they were lifted with silicone casting material (Isomark(®)) or gelatine foil. All lifts were swabbed to recover DNA. It was possible to visualize comparable and identifiable fingerprints on the skin of corpses (16%). In the same categories, magnetic powder (18.4%) yielded better results than black fingerprint powder (13.6%). The number of comparable and identifiable fingerprints decreased on the lifts (12.7%). Isomark(®) (14.9%) was the better lifting material in comparison with gelatine foil (10.1%). In one-third of the samples, DNA could be extracted from the powdered and lifted latents. Black fingerprint powder delivered the better result with a rate of 2.2% for full DNA profiles and profiles useful for exclusion in comparison with 1.8% for the magnetic powder traces. Isomark(®) (3.1%) yielded better results than gelatine foil (0.6%). © 2010 American Academy of Forensic Sciences.

  16. Human papillomavirus DNA detection in sperm using polymerase chain reaction.

    Science.gov (United States)

    Olatunbosun, O; Deneer, H; Pierson, R

    2001-03-01

    To detect human papillomavirus (HPV) in semen and find if sperm washing removes HPV DNA. Amplification by nested polymerase chain reaction (PCR) was used to detect viral DNA sequences in semen samples from 85 volunteers. Forty-five men had historical or clinical evidence of genital HPV infection (study group) and 40 were healthy, clinically HPV-negative semen donors. We detected HPV DNA in the sperm cells of 24 of 45 subjects (53%) with past or current HPV infections in contrast to three of 40 healthy subjects (8%) (P HPV in 21 of 32 subjects (66%) with identifiable lesions and six of 53 (11%) without them (P sperm cells with HPV reduced cellular HPV DNA below detectable levels in only two cases. HPV is present in sperm cells from infected and apparently healthy subjects, and sperm washing does not eliminate the risk of HPV transmission to recipients. We suggest that HPV DNA testing should be done on the semen of prospective donors, and those with positive tests should be excluded from donation.

  17. [Heteroplasmy in human mtDNA control region].

    Science.gov (United States)

    Cao, Yang; Wan, Li-Hua; Gu, Lin-Gang; Huang, Ying-Xue; Xiu, Cong-Xian; Hu, Shu-Hui; Mi, Can

    2006-06-01

    To observe the length heteroplasmy and point heteroplasmy in human mtDNA control region. The peripheral blood, buccal cell, and single hair shaft from 50 individuals and 16 family members, related in their maternallineage were analyzed by direct sequencing, and clones from 20 individuals whose mtDNA sequences have a T-C transition at 16189 nt were sequenced. No point heteroplasmy were observed in peripheral blood, buccal cell, single hair shaft from the same individual, neither in maternally related individuals. Length heteroplasmy was observed in those individuals with a homopolymeric tract and the different clones from the same individual has different proportions of length variants, but the hair shafts from the same individual were very similar to the measurements made from blood DNA. No length heteroplasmy was observed between different tissues from the same individual. mtDNA sequences have a characteristic of high consistency and genetic stability, mtDNA sequencing is a suitable tool for forensic applications such as individual identification.

  18. Analysis of human accelerated DNA regions using archaic hominin genomes.

    Directory of Open Access Journals (Sweden)

    Hernán A Burbano

    Full Text Available Several previous comparisons of the human genome with other primate and vertebrate genomes identified genomic regions that are highly conserved in vertebrate evolution but fast-evolving on the human lineage. These human accelerated regions (HARs may be regions of past adaptive evolution in humans. Alternatively, they may be the result of non-adaptive processes, such as biased gene conversion. We captured and sequenced DNA from a collection of previously published HARs using DNA from an Iberian Neandertal. Combining these new data with shotgun sequence from the Neandertal and Denisova draft genomes, we determine at least one archaic hominin allele for 84% of all positions within HARs. We find that 8% of HAR substitutions are not observed in the archaic hominins and are thus recent in the sense that the derived allele had not come to fixation in the common ancestor of modern humans and archaic hominins. Further, we find that recent substitutions in HARs tend to have come to fixation faster than substitutions elsewhere in the genome and that substitutions in HARs tend to cluster in time, consistent with an episodic rather than a clock-like process underlying HAR evolution. Our catalog of sequence changes in HARs will help prioritize them for functional studies of genomic elements potentially responsible for modern human adaptations.

  19. Analysis of Human Accelerated DNA Regions Using Archaic Hominin Genomes

    Science.gov (United States)

    Burbano, Hernán A.; Green, Richard E.; Maricic, Tomislav; Lalueza-Fox, Carles; de la Rasilla, Marco; Rosas, Antonio; Kelso, Janet; Pollard, Katherine S.; Lachmann, Michael; Pääbo, Svante

    2012-01-01

    Several previous comparisons of the human genome with other primate and vertebrate genomes identified genomic regions that are highly conserved in vertebrate evolution but fast-evolving on the human lineage. These human accelerated regions (HARs) may be regions of past adaptive evolution in humans. Alternatively, they may be the result of non-adaptive processes, such as biased gene conversion. We captured and sequenced DNA from a collection of previously published HARs using DNA from an Iberian Neandertal. Combining these new data with shotgun sequence from the Neandertal and Denisova draft genomes, we determine at least one archaic hominin allele for 84% of all positions within HARs. We find that 8% of HAR substitutions are not observed in the archaic hominins and are thus recent in the sense that the derived allele had not come to fixation in the common ancestor of modern humans and archaic hominins. Further, we find that recent substitutions in HARs tend to have come to fixation faster than substitutions elsewhere in the genome and that substitutions in HARs tend to cluster in time, consistent with an episodic rather than a clock-like process underlying HAR evolution. Our catalog of sequence changes in HARs will help prioritize them for functional studies of genomic elements potentially responsible for modern human adaptations. PMID:22412940

  20. Quantitative comparison between in vivo DNA adduct formation from exposure to selected DNA-reactive carcinogens, natural background levels of DNA adduct formation and tumour incidence in rodent bioassays.

    Science.gov (United States)

    Paini, Alicia; Scholz, Gabriele; Marin-Kuan, Maricel; Schilter, Benoît; O'Brien, John; van Bladeren, Peter J; Rietjens, Ivonne M C M

    2011-09-01

    This study aimed at quantitatively comparing the occurrence/formation of DNA adducts with the carcinogenicity induced by a selection of DNA-reactive genotoxic carcinogens. Contrary to previous efforts, we used a very uniform set of data, limited to in vivo rat liver studies in order to investigate whether a correlation can be obtained, using a benchmark dose (BMD) approach. Dose-response data on both carcinogenicity and in vivo DNA adduct formation were available for six compounds, i.e. 2-acetylaminofluorene, aflatoxin B1, methyleugenol, safrole, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and tamoxifen. BMD(10) values for liver carcinogenicity were calculated using the US Environmental Protection Agency BMD software. DNA adduct levels at this dose were extrapolated assuming linearity of the DNA adduct dose response. In addition, the levels of DNA adducts at the BMD(10) were compared to available data on endogenous background DNA damage in the target organ. Although for an individual carcinogen the tumour response increases when adduct levels increase, our results demonstrate that when comparing different carcinogens, no quantitative correlation exists between the level of DNA adduct formation and carcinogenicity. These data confirm that the quantity of DNA adducts formed by a DNA-reactive compound is not a carcinogenicity predictor but that other factors such as type of adduct and mutagenic potential may be equally relevant. Moreover, comparison to background DNA damage supports the notion that the mere occurrence of DNA adducts above or below the level of endogenous DNA damage is neither correlated to development of cancer. These data strongly emphasise the need to apply the mode of action framework to understand the contribution of other biological effect markers playing a role in carcinogenicity.

  1. Reef-associated crustacean fauna: biodiversity estimates using semi-quantitative sampling and DNA barcoding

    Science.gov (United States)

    Plaisance, L.; Knowlton, N.; Paulay, G.; Meyer, C.

    2009-12-01

    The cryptofauna associated with coral reefs accounts for a major part of the biodiversity in these ecosystems but has been largely overlooked in biodiversity estimates because the organisms are hard to collect and identify. We combine a semi-quantitative sampling design and a DNA barcoding approach to provide metrics for the diversity of reef-associated crustacean. Twenty-two similar-sized dead heads of Pocillopora were sampled at 10 m depth from five central Pacific Ocean localities (four atolls in the Northern Line Islands and in Moorea, French Polynesia). All crustaceans were removed, and partial cytochrome oxidase subunit I was sequenced from 403 individuals, yielding 135 distinct taxa using a species-level criterion of 5% similarity. Most crustacean species were rare; 44% of the OTUs were represented by a single individual, and an additional 33% were represented by several specimens found only in one of the five localities. The Northern Line Islands and Moorea shared only 11 OTUs. Total numbers estimated by species richness statistics (Chao1 and ACE) suggest at least 90 species of crustaceans in Moorea and 150 in the Northern Line Islands for this habitat type. However, rarefaction curves for each region failed to approach an asymptote, and Chao1 and ACE estimators did not stabilize after sampling eight heads in Moorea, so even these diversity figures are underestimates. Nevertheless, even this modest sampling effort from a very limited habitat resulted in surprisingly high species numbers.

  2. A Bayesian method for calculating real-time quantitative PCR calibration curves using absolute plasmid DNA standards

    Directory of Open Access Journals (Sweden)

    Haugland Richard A

    2008-02-01

    Full Text Available Abstract Background In real-time quantitative PCR studies using absolute plasmid DNA standards, a calibration curve is developed to estimate an unknown DNA concentration. However, potential differences in the amplification performance of plasmid DNA compared to genomic DNA standards are often ignored in calibration calculations and in some cases impossible to characterize. A flexible statistical method that can account for uncertainty between plasmid and genomic DNA targets, replicate testing, and experiment-to-experiment variability is needed to estimate calibration curve parameters such as intercept and slope. Here we report the use of a Bayesian approach to generate calibration curves for the enumeration of target DNA from genomic DNA samples using absolute plasmid DNA standards. Results Instead of the two traditional methods (classical and inverse, a Monte Carlo Markov Chain (MCMC estimation was used to generate single, master, and modified calibration curves. The mean and the percentiles of the posterior distribution were used as point and interval estimates of unknown parameters such as intercepts, slopes and DNA concentrations. The software WinBUGS was used to perform all simulations and to generate the posterior distributions of all the unknown parameters of interest. Conclusion The Bayesian approach defined in this study allowed for the estimation of DNA concentrations from environmental samples using absolute standard curves generated by real-time qPCR. The approach accounted for uncertainty from multiple sources such as experiment-to-experiment variation, variability between replicate measurements, as well as uncertainty introduced when employing calibration curves generated from absolute plasmid DNA standards.

  3. FXR silencing in human colon cancer by DNA methylation and KRAS signaling.

    Science.gov (United States)

    Bailey, Ann M; Zhan, Le; Maru, Dipen; Shureiqi, Imad; Pickering, Curtis R; Kiriakova, Galina; Izzo, Julie; He, Nan; Wei, Caimiao; Baladandayuthapani, Veerabhadran; Liang, Han; Kopetz, Scott; Powis, Garth; Guo, Grace L

    2014-01-01

    Farnesoid X receptor (FXR) is a bile acid nuclear receptor described through mouse knockout studies as a tumor suppressor for the development of colon adenocarcinomas. This study investigates the regulation of FXR in the development of human colon cancer. We used immunohistochemistry of FXR in normal tissue (n = 238), polyps (n = 32), and adenocarcinomas, staged I-IV (n = 43, 39, 68, and 9), of the colon; RT-quantitative PCR, reverse-phase protein array, and Western blot analysis in 15 colon cancer cell lines; NR1H4 promoter methylation and mRNA expression in colon cancer samples from The Cancer Genome Atlas; DNA methyltransferase inhibition; methyl-DNA immunoprecipitation (MeDIP); bisulfite sequencing; and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) knockdown assessment to investigate FXR regulation in colon cancer development. Immunohistochemistry and quantitative RT-PCR revealed that expression and function of FXR was reduced in precancerous lesions and silenced in a majority of stage I-IV tumors. FXR expression negatively correlated with phosphatidylinositol-4, 5-bisphosphate 3 kinase signaling and the epithelial-to-mesenchymal transition. The NR1H4 promoter is methylated in ~12% colon cancer The Cancer Genome Atlas samples, and methylation patterns segregate with tumor subtypes. Inhibition of DNA methylation and KRAS silencing both increased FXR expression. FXR expression is decreased early in human colon cancer progression, and both DNA methylation and KRAS signaling may be contributing factors to FXR silencing. FXR potentially suppresses epithelial-to-mesenchymal transition and other oncogenic signaling cascades, and restoration of FXR activity, by blocking silencing mechanisms or increasing residual FXR activity, represents promising therapeutic options for the treatment of colon cancer.

  4. Nonextensive statistical approach to non-coding human DNA

    Science.gov (United States)

    Oikonomou, Th.; Provata, A.; Tirnakli, U.

    2008-04-01

    We use q-exponential distributions, which maximize the nonextensive entropy Sq (defined as Sq≡(1-∑ipiq)/(q-1)), to study the size distributions of non-coding DNA (including introns and intergenic regions) in all human chromosomes. We show that the value of the exponent q describing the non-coding size distributions is similar for all chromosomes and varies between 2≤q≤2.3 with the exception of chromosomes X and Y.

  5. Defining functional DNA elements in the human genome

    Science.gov (United States)

    Kellis, Manolis; Wold, Barbara; Snyder, Michael P.; Bernstein, Bradley E.; Kundaje, Anshul; Marinov, Georgi K.; Ward, Lucas D.; Birney, Ewan; Crawford, Gregory E.; Dekker, Job; Dunham, Ian; Elnitski, Laura L.; Farnham, Peggy J.; Feingold, Elise A.; Gerstein, Mark; Giddings, Morgan C.; Gilbert, David M.; Gingeras, Thomas R.; Green, Eric D.; Guigo, Roderic; Hubbard, Tim; Kent, Jim; Lieb, Jason D.; Myers, Richard M.; Pazin, Michael J.; Ren, Bing; Stamatoyannopoulos, John A.; Weng, Zhiping; White, Kevin P.; Hardison, Ross C.

    2014-01-01

    With the completion of the human genome sequence, attention turned to identifying and annotating its functional DNA elements. As a complement to genetic and comparative genomics approaches, the Encyclopedia of DNA Elements Project was launched to contribute maps of RNA transcripts, transcriptional regulator binding sites, and chromatin states in many cell types. The resulting genome-wide data reveal sites of biochemical activity with high positional resolution and cell type specificity that facilitate studies of gene regulation and interpretation of noncoding variants associated with human disease. However, the biochemically active regions cover a much larger fraction of the genome than do evolutionarily conserved regions, raising the question of whether nonconserved but biochemically active regions are truly functional. Here, we review the strengths and limitations of biochemical, evolutionary, and genetic approaches for defining functional DNA segments, potential sources for the observed differences in estimated genomic coverage, and the biological implications of these discrepancies. We also analyze the relationship between signal intensity, genomic coverage, and evolutionary conservation. Our results reinforce the principle that each approach provides complementary information and that we need to use combinations of all three to elucidate genome function in human biology and disease. PMID:24753594

  6. Novel quantitative pigmentation phenotyping enhances genetic association, epistasis, and prediction of human eye colour

    Science.gov (United States)

    Wollstein, Andreas; Walsh, Susan; Liu, Fan; Chakravarthy, Usha; Rahu, Mati; Seland, Johan H.; Soubrane, Gisèle; Tomazzoli, Laura; Topouzis, Fotis; Vingerling, Johannes R.; Vioque, Jesus; Böhringer, Stefan; Fletcher, Astrid E.; Kayser, Manfred

    2017-01-01

    Success of genetic association and the prediction of phenotypic traits from DNA are known to depend on the accuracy of phenotype characterization, amongst other parameters. To overcome limitations in the characterization of human iris pigmentation, we introduce a fully automated approach that specifies the areal proportions proposed to represent differing pigmentation types, such as pheomelanin, eumelanin, and non-pigmented areas within the iris. We demonstrate the utility of this approach using high-resolution digital eye imagery and genotype data from 12 selected SNPs from over 3000 European samples of seven populations that are part of the EUREYE study. In comparison to previous quantification approaches, (1) we achieved an overall improvement in eye colour phenotyping, which provides a better separation of manually defined eye colour categories. (2) Single nucleotide polymorphisms (SNPs) known to be involved in human eye colour variation showed stronger associations with our approach. (3) We found new and confirmed previously noted SNP-SNP interactions. (4) We increased SNP-based prediction accuracy of quantitative eye colour. Our findings exemplify that precise quantification using the perceived biological basis of pigmentation leads to enhanced genetic association and prediction of eye colour. We expect our approach to deliver new pigmentation genes when applied to genome-wide association testing. PMID:28240252

  7. Transcription-factor occupancy at HOT regions quantitatively predicts RNA polymerase recruitment in five human cell lines.

    KAUST Repository

    Foley, Joseph W

    2013-10-20

    BACKGROUND: High-occupancy target (HOT) regions are compact genome loci occupied by many different transcription factors (TFs). HOT regions were initially defined in invertebrate model organisms, and we here show that they are a ubiquitous feature of the human gene-regulation landscape. RESULTS: We identified HOT regions by a comprehensive analysis of ChIP-seq data from 96 DNA-associated proteins in 5 human cell lines. Most HOT regions co-localize with RNA polymerase II binding sites, but many are not near the promoters of annotated genes. At HOT promoters, TF occupancy is strongly predictive of transcription preinitiation complex recruitment and moderately predictive of initiating Pol II recruitment, but only weakly predictive of elongating Pol II and RNA transcript abundance. TF occupancy varies quantitatively within human HOT regions; we used this variation to discover novel associations between TFs. The sequence motif associated with any given TF\\'s direct DNA binding is somewhat predictive of its empirical occupancy, but a great deal of occupancy occurs at sites without the TF\\'s motif, implying indirect recruitment by another TF whose motif is present. CONCLUSIONS: Mammalian HOT regions are regulatory hubs that integrate the signals from diverse regulatory pathways to quantitatively tune the promoter for RNA polymerase II recruitment.

  8. Quantitative proteome profiling of normal human circulating microparticles

    DEFF Research Database (Denmark)

    Østergaard, Ole; Nielsen, Christoffer T; Iversen, Line V

    2012-01-01

    Circulating microparticles (MPs) are produced as part of normal physiology. Their numbers, origin, and composition change in pathology. Despite this, the normal MP proteome has not yet been characterized with standardized high-resolution methods. We here quantitatively profile the normal MP...... proteome using nano-LC-MS/MS on an LTQ-Orbitrap with optimized sample collection, preparation, and analysis of 12 different normal samples. Analytical and procedural variation were estimated in triply processed samples analyzed in triplicate from two different donors. Label-free quantitation was validated...... by the correlation of cytoskeletal protein intensities with MP numbers obtained by flow cytometry. Finally, the validity of using pooled samples was evaluated using overlap protein identification numbers and multivariate data analysis. Using conservative parameters, 536 different unique proteins were quantitated...

  9. The study of human Y chromosome variation through ancient DNA.

    Science.gov (United States)

    Kivisild, Toomas

    2017-05-01

    High throughput sequencing methods have completely transformed the study of human Y chromosome variation by offering a genome-scale view on genetic variation retrieved from ancient human remains in context of a growing number of high coverage whole Y chromosome sequence data from living populations from across the world. The ancient Y chromosome sequences are providing us the first exciting glimpses into the past variation of male-specific compartment of the genome and the opportunity to evaluate models based on previously made inferences from patterns of genetic variation in living populations. Analyses of the ancient Y chromosome sequences are challenging not only because of issues generally related to ancient DNA work, such as DNA damage-induced mutations and low content of endogenous DNA in most human remains, but also because of specific properties of the Y chromosome, such as its highly repetitive nature and high homology with the X chromosome. Shotgun sequencing of uniquely mapping regions of the Y chromosomes to sufficiently high coverage is still challenging and costly in poorly preserved samples. To increase the coverage of specific target SNPs capture-based methods have been developed and used in recent years to generate Y chromosome sequence data from hundreds of prehistoric skeletal remains. Besides the prospects of testing directly as how much genetic change in a given time period has accompanied changes in material culture the sequencing of ancient Y chromosomes allows us also to better understand the rate at which mutations accumulate and get fixed over time. This review considers genome-scale evidence on ancient Y chromosome diversity that has recently started to accumulate in geographic areas favourable to DNA preservation. More specifically the review focuses on examples of regional continuity and change of the Y chromosome haplogroups in North Eurasia and in the New World.

  10. Development and validation of open-source software for DNA mixture interpretation based on a quantitative continuous model.

    Directory of Open Access Journals (Sweden)

    Sho Manabe

    Full Text Available In criminal investigations, forensic scientists need to evaluate DNA mixtures. The estimation of the number of contributors and evaluation of the contribution of a person of interest (POI from these samples are challenging. In this study, we developed a new open-source software "Kongoh" for interpreting DNA mixture based on a quantitative continuous model. The model uses quantitative information of peak heights in the DNA profile and considers the effect of artifacts and allelic drop-out. By using this software, the likelihoods of 1-4 persons' contributions are calculated, and the most optimal number of contributors is automatically determined; this differs from other open-source software. Therefore, we can eliminate the need to manually determine the number of contributors before the analysis. Kongoh also considers allele- or locus-specific effects of biological parameters based on the experimental data. We then validated Kongoh by calculating the likelihood ratio (LR of a POI's contribution in true contributors and non-contributors by using 2-4 person mixtures analyzed through a 15 short tandem repeat typing system. Most LR values obtained from Kongoh during true-contributor testing strongly supported the POI's contribution even for small amounts or degraded DNA samples. Kongoh correctly rejected a false hypothesis in the non-contributor testing, generated reproducible LR values, and demonstrated higher accuracy of the estimated number of contributors than another software based on the quantitative continuous model. Therefore, Kongoh is useful in accurately interpreting DNA evidence like mixtures and small amounts or degraded DNA samples.

  11. Development and validation of open-source software for DNA mixture interpretation based on a quantitative continuous model.

    Science.gov (United States)

    Manabe, Sho; Morimoto, Chie; Hamano, Yuya; Fujimoto, Shuntaro; Tamaki, Keiji

    2017-01-01

    In criminal investigations, forensic scientists need to evaluate DNA mixtures. The estimation of the number of contributors and evaluation of the contribution of a person of interest (POI) from these samples are challenging. In this study, we developed a new open-source software "Kongoh" for interpreting DNA mixture based on a quantitative continuous model. The model uses quantitative information of peak heights in the DNA profile and considers the effect of artifacts and allelic drop-out. By using this software, the likelihoods of 1-4 persons' contributions are calculated, and the most optimal number of contributors is automatically determined; this differs from other open-source software. Therefore, we can eliminate the need to manually determine the number of contributors before the analysis. Kongoh also considers allele- or locus-specific effects of biological parameters based on the experimental data. We then validated Kongoh by calculating the likelihood ratio (LR) of a POI's contribution in true contributors and non-contributors by using 2-4 person mixtures analyzed through a 15 short tandem repeat typing system. Most LR values obtained from Kongoh during true-contributor testing strongly supported the POI's contribution even for small amounts or degraded DNA samples. Kongoh correctly rejected a false hypothesis in the non-contributor testing, generated reproducible LR values, and demonstrated higher accuracy of the estimated number of contributors than another software based on the quantitative continuous model. Therefore, Kongoh is useful in accurately interpreting DNA evidence like mixtures and small amounts or degraded DNA samples.

  12. Quantitative cell-free DNA, KRAS, and BRAF mutations in plasma from patients with metastatic colorectal cancer during treatment with cetuximab and irinotecan

    DEFF Research Database (Denmark)

    Spindler, Karen-Lise Garm; Pallisgaard, Niels; Vogelius, Ivan Storgaard

    2012-01-01

    The present study investigated the levels of circulating cell-free DNA (cfDNA) in plasma from patients with metastatic colorectal cancer (mCRC) in relation to third-line treatment with cetuximab and irinotecan and the quantitative relationship of cfDNA with tumor-specific mutations in plasma....

  13. Holes influence the mutation spectrum of human mitochondrial DNA

    Science.gov (United States)

    Villagran, Martha; Miller, John

    Mutations drive evolution and disease, showing highly non-random patterns of variant frequency vs. nucleotide position. We use computational DNA hole spectroscopy [M.Y. Suarez-Villagran & J.H. Miller, Sci. Rep. 5, 13571 (2015)] to reveal sites of enhanced hole probability in selected regions of human mitochondrial DNA. A hole is a mobile site of positive charge created when an electron is removed, for example by radiation or contact with a mutagenic agent. The hole spectra are quantum mechanically computed using a two-stranded tight binding model of DNA. We observe significant correlation between spectra of hole probabilities and of genetic variation frequencies from the MITOMAP database. These results suggest that hole-enhanced mutation mechanisms exert a substantial, perhaps dominant, influence on mutation patterns in DNA. One example is where a trapped hole induces a hydrogen bond shift, known as tautomerization, which then triggers a base-pair mismatch during replication. Our results deepen overall understanding of sequence specific mutation rates, encompassing both hotspots and cold spots, which drive molecular evolution.

  14. DNA methylation variation of human-specific Alu repeats

    Science.gov (United States)

    Bakshi, Arundhati; Herke, Scott W.; Batzer, Mark A.; Kim, Joomyeong

    2016-01-01

    ABSTRACT DNA methylation is the major repression mechanism for human retrotransposons, such as the Alu family. Here, we have determined the methylation levels associated with 5238 loci belonging to 2 Alu subfamilies, AluYa5 and AluYb8, using high-throughput targeted repeat element bisulfite sequencing (HT-TREBS). The results indicate that ∼90% of loci are repressed by high methylation levels. Of the remaining loci, many of the hypomethylated elements are found near gene promoters and show high levels of DNA methylation variation. We have characterized this variation in the context of tumorigenesis and interindividual differences. Comparison of a primary breast tumor and its matched normal tissue revealed early DNA methylation changes in ∼1% of AluYb8 elements in response to tumorigenesis. Simultaneously, AluYa5/Yb8 elements proximal to promoters also showed differences in methylation of up to one order of magnitude, even between normal individuals. Overall, the current study demonstrates that early loss of methylation occurs during tumorigenesis in a subset of young Alu elements, suggesting their potential clinical relevance. However, approaches such as deep-bisulfite-sequencing of individual loci using HT-TREBS are required to distinguish clinically relevant loci from the background observed for AluYa5/Yb8 elements in general with regard to high levels of interindividual variation in DNA methylation. PMID:26890526

  15. Environmental car exhaust pollution damages human sperm chromatin and DNA.

    Science.gov (United States)

    Calogero, A E; La Vignera, S; Condorelli, R A; Perdichizzi, A; Valenti, D; Asero, P; Carbone, U; Boggia, B; De Rosa, N; Lombardi, G; D'Agata, R; Vicari, L O; Vicari, E; De Rosa, M

    2011-06-01

    The adverse role of traffic pollutants on male fertility is well known. Aim of this study was to evaluate their effects on sperm chromatin/DNA integrity. To accomplish this, 36 men working at motorway tollgates and 32 unexposed healthy men (controls) were enrolled. All of them were interviewed about their lifestyle. Hormone, semen samples, and environmental and biological markers of pollution were evaluated. Sperm chromatin and DNA integrity were evaluated by flow cytometry following propidium iodide staining and TUNEL assay, respectively. LH, FSH, and testosterone serum levels were within the normal range in tollgate workers. Sperm concentration, total sperm count, total and progressive motility, and normal forms were significantly lower in these men compared with controls. Motorway tollgate workers had a significantly higher percentage of spermatozoa with damaged chromatin and DNA fragmentation, a late sign of apoptosis, compared with controls. A significant direct correlation was found between spermatozoa with damaged chromatin or fragmented DNA and the length of occupational exposure, suggesting a time-dependent relationship. This study showed that car exhaust exposure has a genotoxic effect on human spermatozoa. This may be of relevant importance not only for the reproductive performance of the men exposed, but also for the offspring health.

  16. Multivalent human papillomavirus l1 DNA vaccination utilizing electroporation.

    Directory of Open Access Journals (Sweden)

    Kihyuck Kwak

    Full Text Available Naked DNA vaccines can be manufactured simply and are stable at ambient temperature, but require improved delivery technologies to boost immunogenicity. Here we explore in vivo electroporation for multivalent codon-optimized human papillomavirus (HPV L1 and L2 DNA vaccination.Balb/c mice were vaccinated three times at two week intervals with a fusion protein comprising L2 residues ∼11-88 of 8 different HPV types (11-88×8 or its DNA expression vector, DNA constructs expressing L1 only or L1+L2 of a single HPV type, or as a mixture of several high-risk HPV types and administered utilizing electroporation, i.m. injection or gene gun. Serum was collected two weeks and 3 months after the last vaccination. Sera from immunized mice were tested for in-vitro neutralization titer, and protective efficacy upon passive transfer to naive mice and vaginal HPV challenge. Heterotypic interactions between L1 proteins of HPV6, HPV16 and HPV18 in 293TT cells were tested by co-precipitation using type-specific monoclonal antibodies.Electroporation with L2 multimer DNA did not elicit detectable antibody titer, whereas DNA expressing L1 or L1+L2 induced L1-specific, type-restricted neutralizing antibodies, with titers approaching those induced by Gardasil. Co-expression of L2 neither augmented L1-specific responses nor induced L2-specific antibodies. Delivery of HPV L1 DNA via in vivo electroporation produces a stronger antibody response compared to i.m. injection or i.d. ballistic delivery via gene gun. Reduced neutralizing antibody titers were observed for certain types when vaccinating with a mixture of L1 (or L1+L2 vectors of multiple HPV types, likely resulting from heterotypic L1 interactions observed in co-immunoprecipitation studies. High titers were restored by vaccinating with individual constructs at different sites, or partially recovered by co-expression of L2, such that durable protective antibody titers were achieved for each type

  17. The DNA methylome of human peripheral blood mononuclear cells.

    Directory of Open Access Journals (Sweden)

    Yingrui Li

    2010-11-01

    Full Text Available DNA methylation plays an important role in biological processes in human health and disease. Recent technological advances allow unbiased whole-genome DNA methylation (methylome analysis to be carried out on human cells. Using whole-genome bisulfite sequencing at 24.7-fold coverage (12.3-fold per strand, we report a comprehensive (92.62% methylome and analysis of the unique sequences in human peripheral blood mononuclear cells (PBMC from the same Asian individual whose genome was deciphered in the YH project. PBMC constitute an important source for clinical blood tests world-wide. We found that 68.4% of CpG sites and 80% displayed allele-specific expression (ASE. These data demonstrate that ASM is a recurrent phenomenon and is highly correlated with ASE in human PBMCs. Together with recently reported similar studies, our study provides a comprehensive resource for future epigenomic research and confirms new sequencing technology as a paradigm for large-scale epigenomics studies.

  18. A promising DNA methylation signature for the triage of high-risk human papillomavirus DNA-positive women.

    Directory of Open Access Journals (Sweden)

    Alfred Hansel

    Full Text Available High-risk human papillomavirus (hrHPV-DNA testing is frequently performed parallel to cytology for the detection of high-grade dysplasia and cervical cancer particularly in women above 30 years of age. Although highly sensitive, hrHPV testing cannot distinguish between HPV-positive women with or without clinically relevant lesions. However, in principle discrimination is possible on the basis of DNA methylation markers. In order to identify novel DNA regions which allow an effective triage of hrHPV-positive cases, hypermethylated DNA enriched from cervical cancers was compared with that from cervical scrapes of HPV16-positive cases with no evidence for disease by CpG island microarray hybridization. The most promising marker regions were validated by quantitative methylation-specific PCR (qMSP using DNA from archived cervical tissues and cervical scrapes. The performance of these markers was then determined in an independent set of 217 hrHPV-positive cervical scrapes from outpatients with histopathological verification. A methylation signature comprising the 5' regions of the genes DLX1, ITGA4, RXFP3, SOX17 and ZNF671 specific for CIN3 and cervical cancer (termed CIN3+ was identified and validated. A high detection rate of CIN3+ was obtained if at least 2 of the 5 markers were methylated. In the subsequent cross-sectional study all cervical carcinomas (n = 19 and 56% (13/23 of CIN3 were identified by this algorithm. Only 10% (11/105 of hrHPV-positive women without histological evidence of cervical disease were scored positive by the methylation assay. Of note is that the detection rate of CIN3 differed between age groups. Eight of nine CIN3 were detected among women ≥30 years of age but only five of fourteen among <30 year old group (p = 0.03. The specificity for CIN3+ in the older age group was 76.6% (95% CI 65.6-85.5%. Clinical validation studies are required to determine the usefulness of these novel markers for triage after primary

  19. Duplex Alu Screening for Degraded DNA of Skeletal Human Remains

    Directory of Open Access Journals (Sweden)

    Fabian Haß

    2017-10-01

    Full Text Available The human-specific Alu elements, belonging to the class of Short INterspersed Elements (SINEs, have been shown to be a powerful tool for population genetic studies. An earlier study in this department showed that it was possible to analyze Alu presence/absence in 3000-year-old skeletal human remains from the Bronze Age Lichtenstein cave in Lower Saxony, Germany. We developed duplex Alu screening PCRs with flanking primers for two Alu elements, each combined with a single internal Alu primer. By adding an internal primer, the approximately 400–500 bp presence signals of Alu elements can be detected within a range of less than 200 bp. Thus, our PCR approach is suited for highly fragmented ancient DNA samples, whereas NGS analyses frequently are unable to handle repetitive elements. With this analysis system, we examined remains of 12 individuals from the Lichtenstein cave with different degrees of DNA degradation. The duplex PCRs showed fully informative amplification results for all of the chosen Alu loci in eight of the 12 samples. Our analysis system showed that Alu presence/absence analysis is possible in samples with different degrees of DNA degradation and it reduces the amount of valuable skeletal material needed by a factor of four, as compared with a singleplex approach.

  20. Genome-Wide Analysis of DNA Methylation in Human Amnion

    Directory of Open Access Journals (Sweden)

    Jinsil Kim

    2013-01-01

    Full Text Available The amnion is a specialized tissue in contact with the amniotic fluid, which is in a constantly changing state. To investigate the importance of epigenetic events in this tissue in the physiology and pathophysiology of pregnancy, we performed genome-wide DNA methylation profiling of human amnion from term (with and without labor and preterm deliveries. Using the Illumina Infinium HumanMethylation27 BeadChip, we identified genes exhibiting differential methylation associated with normal labor and preterm birth. Functional analysis of the differentially methylated genes revealed biologically relevant enriched gene sets. Bisulfite sequencing analysis of the promoter region of the oxytocin receptor (OXTR gene detected two CpG dinucleotides showing significant methylation differences among the three groups of samples. Hypermethylation of the CpG island of the solute carrier family 30 member 3 (SLC30A3 gene in preterm amnion was confirmed by methylation-specific PCR. This work provides preliminary evidence that DNA methylation changes in the amnion may be at least partially involved in the physiological process of labor and the etiology of preterm birth and suggests that DNA methylation profiles, in combination with other biological data, may provide valuable insight into the mechanisms underlying normal and pathological pregnancies.

  1. High prevalence of Methanobrevibacter smithii and Methanosphaera stadtmanae detected in the human gut using an improved DNA detection protocol.

    Directory of Open Access Journals (Sweden)

    Bédis Dridi

    Full Text Available BACKGROUND: The low and variable prevalence of Methanobrevibacter smithii and Methanosphaera stadtmanae DNA in human stool contrasts with the paramount role of these methanogenic Archaea in digestion processes. We hypothesized that this contrast is a consequence of the inefficiencies of current protocols for archaeon DNA extraction. We developed a new protocol for the extraction and PCR-based detection of M. smithii and M. stadtmanae DNA in human stool. METHODOLOGY/PRINCIPAL FINDINGS: Stool specimens collected from 700 individuals were filtered, mechanically lysed twice, and incubated overnight with proteinase K prior to DNA extraction using a commercial DNA extraction kit. Total DNA was used as a template for quantitative real-time PCR targeting M. smithii and M. stadtmanae 16S rRNA and rpoB genes. Amplification of 16S rRNA and rpoB yielded positive detection of M. smithii in 95.7% and M. stadtmanae in 29.4% of specimens. Sequencing of 16S rRNA gene PCR products from 30 randomly selected specimens (15 for M. smithii and 15 for M. stadtmanae yielded a sequence similarity of 99-100% using the reference M. smithii ATCC 35061 and M. stadtmanae DSM 3091 sequences. CONCLUSIONS/SIGNIFICANCE: In contrast to previous reports, these data indicate a high prevalence of the methanogens M. smithii and M. stadtmanae in the human gut, with the former being an almost ubiquitous inhabitant of the intestinal microbiome.

  2. The use of dimorphic Alu insertions in human DNA fingerprinting

    Energy Technology Data Exchange (ETDEWEB)

    Novick, G.E.; Gonzalez, T.; Garrison, J.; Novick, C.C.; Herrera, R.J. [Florida International Univ., Miami, FL (United States). Dept. of Biological Sciences; Batzer, M.A. [Lawrence Livermore National Lab., CA (United States); Deininger, P.L. [Louisiana State Univ., New Orleans, LA (United States). Medical Center

    1992-12-04

    We have characterized certain Human Specific Alu Insertions as either dimorphic (TPA25, PV92, APO), sightly dimorphic (C2N4 and C4N4) or monomorphic (C3N1, C4N6, C4N2, C4N5, C4N8), based on studies of Caucasian, Asian, American Black and African Black populations. Our approach is based upon: (1) PCR amplification using primers directed to the sequences that flank the site of insertion of the different Alu elements studied; (2) gel electrophoresis and scoring according to the presence or absence of an Alu insertion in one or both homologous chromosomes; (3) allelic frequencies calculated and compared according to Hardy-Weinberg equilibrium. Our DNA fingerprinting procedure using PCR amplification of dimorphic Human Specific Alu insertions, is stable enough to be used not only as a tool for genetic mapping but also to characterize populations, study migrational patterns and track the inheritance of human genetic disorders.

  3. Electron probe microanalysis of permanent human enamel and dentine. A methodological and quantitative study

    OpenAIRE

    Sánchez-Quevedo, M.C.; Nieto-Albano, O.H.; García, J. M.; Gómez de Ferraris, M.E.; Campos, Antonio

    1998-01-01

    Sample preparation of dental tissues for quantitative electron microprobe analysis has not been critically examined because of the highly mineralized nature of these structures. The present study was designed to establish the most suitable method for the electron probe quantitative determination of calcium in human permanent enamel and dentine while preserving the morphological features. Comparisons of quantitative data obtained with air-drying and freeze-dryin...

  4. Synthesis and quantitative structure-activity relationship of imidazotetrazine prodrugs with activity independent of O6-methylguanine-DNA-methyltransferase, DNA mismatch repair, and p53.

    Science.gov (United States)

    Pletsas, Dimitrios; Garelnabi, Elrashied A E; Li, Li; Phillips, Roger M; Wheelhouse, Richard T

    2013-09-12

    The antitumor prodrug temozolomide is compromised by its dependence for activity on DNA mismatch repair (MMR) and the repair of the chemosensitive DNA lesion, O6-methylguanine (O6-MeG), by O6-methylguanine-DNA-methyltransferase (E.C. 2.1.1.63, MGMT). Tumor response is also dependent on wild-type p53. Novel 3-(2-anilinoethyl)-substituted imidazotetrazines are reported that have activity independent of MGMT, MMR, and p53. This is achieved through a switch of mechanism so that bioactivity derives from imidazotetrazine-generated arylaziridinium ions that principally modify guanine-N7 sites on DNA. Mono- and bifunctional analogues are reported, and a quantitative structure-activity relationship (QSAR) study identified the p-tolyl-substituted bifunctional congener as optimized for potency, MGMT-independence, and MMR-independence. NCI60 data show the tumor cell response is distinct from other imidazotetrazines and DNA-guanine-N7 active agents such as nitrogen mustards and cisplatin. The new imidazotetrazine compounds are promising agents for further development, and their improved in vitro activity validates the principles on which they were designed.

  5. DNA-binding polarity of human replication protein A positions nucleases in nucleotide excision repair

    NARCIS (Netherlands)

    W.L. de Laat (Wouter); E. Appeldoorn (Esther); K. Sugasawa (Kaoru); E.P.W.C. Weterings (Eric); J.H.J. Hoeijmakers (Jan); N.G.J. Jaspers (Nicolaas)

    1998-01-01

    textabstractThe human single-stranded DNA-binding replication A protein (RPA) is involved in various DNA-processing events. By comparing the affinity of hRPA for artificial DNA hairpin structures with 3'- or 5'-protruding single-stranded arms, we found that hRPA binds ssDNA with a

  6. Depletion of polycistronic transcripts using short interfering RNAs: cDNA synthesis method affects levels of non-targeted genes determined by quantitative PCR.

    Science.gov (United States)

    Hanning, Jennifer E; Groves, Ian J; Pett, Mark R; Coleman, Nicholas

    2013-05-21

    Short interfering RNAs (siRNAs) are often used to deplete viral polycistronic transcripts, such as those encoded by human papillomavirus (HPV). There are conflicting data in the literature concerning how siRNAs targeting one HPV gene can affect levels of other genes in the polycistronic transcripts. We hypothesised that the conflict might be partly explained by the method of cDNA synthesis used prior to transcript quantification. We treated HPV16-positive cervical keratinocytes with siRNAs targeting the HPV16 E7 gene and used quantitative PCR to compare transcript levels of E7 with those of E6 and E2, viral genes located upstream and downstream of the target site respectively. We compared our findings from cDNA generated using oligo-dT primers alone with those from cDNA generated using a combination of random hexamer and oligo-dT primers. Our data show that when polycistronic transcripts are targeted by siRNAs, there is a period when untranslatable cleaved mRNA upstream of the siRNA binding site remains detectable by PCR, if cDNA is generated using random hexamer primers. Such false indications of mRNA abundance are avoided using oligo-dT primers. The period corresponds to the time taken for siRNA activity and degradation of the cleaved transcripts. Genes downstream of the siRNA binding site are detectable during this interval, regardless of how the cDNA is generated. These data emphasise the importance of the cDNA synthesis method used when measuring transcript abundance following siRNA depletion of polycistronic transcripts. They provide a partial explanation for erroneous reports suggesting that siRNAs targeting HPV E7 can have gene-specific effects.

  7. Core-shell silica nanoparticles synthesized for quantitative study of DNA cleavage by laser-induced fluorescence microscopy.

    Science.gov (United States)

    Ko, Jungaa; Lim, H B

    2011-02-01

    Dye-doped silica nanoparticles (C dots) were synthesized in reverse microemulsions and used to quantitatively examine DNA cleavage in the presence of transition metal ions. The cores were synthesized as fluorescein isothiocyanate (FITC)-doped silica nanoparticles and the shells' surfaces were modified with single-stranded DNA oligomers tagged with Cy5 fluorophores. DNA cleavage induced by heavy metal ions was estimated by comparing the fluorescence of Cy5 before and after reaction with metal ions. For this, a lab-built laser-induced fluorescence microscope equipped with a charge coupled device (CCD) camera, for imaging, and photomultiplier tube, for photon counting, was used. FITC fluorescence from the core was measured as an internal standard to compensate for possible loss of the beads during the treatment. The cleavage of DNA in air in the presence of Pb(2+), Cd(2+), and Hg(2+) at 1 ng/mL was found to be 14%, 6%, and 20%, respectively, and was significantly reduced to below 9% under N(2) gas, indicating that the main cleavage source was oxygen in air. The most significant DNA cleavage was observed with the addition of hydrogen peroxide. This analytical method using dye-doped C dots provided convenient handling and quantification of the estimation of metal-DNA interaction with a detection limit of 34.9 pmol/mL.

  8. Hydroxytyrosol Protects against Oxidative DNA Damage in Human Breast Cells

    Directory of Open Access Journals (Sweden)

    José J. Gaforio

    2011-10-01

    Full Text Available Over recent years, several studies have related olive oil ingestion to a low incidence of several diseases, including breast cancer. Hydroxytyrosol and tyrosol are two of the major phenols present in virgin olive oils. Despite the fact that they have been linked to cancer prevention, there is no evidence that clarifies their effect in human breast tumor and non-tumor cells. In the present work, we present hydroxytyrosol and tyrosol’s effects in human breast cell lines. Our results show that hydroxytyrosol acts as a more efficient free radical scavenger than tyrosol, but both fail to affect cell proliferation rates, cell cycle profile or cell apoptosis in human mammary epithelial cells (MCF10A or breast cancer cells (MDA-MB-231 and MCF7. We found that hydroxytyrosol decreases the intracellular reactive oxygen species (ROS level in MCF10A cells but not in MCF7 or MDA-MB-231 cells while very high amounts of tyrosol is needed to decrease the ROS level in MCF10A cells. Interestingly, hydroxytyrosol prevents oxidative DNA damage in the three breast cell lines. Therefore, our data suggest that simple phenol hydroxytyrosol could contribute to a lower incidence of breast cancer in populations that consume virgin olive oil due to its antioxidant activity and its protection against oxidative DNA damage in mammary cells.

  9. Isolating human DNA repair genes using rodent-cell mutants

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

    1987-03-23

    The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab.

  10. Robotics for recombinant DNA and human genetics research

    Energy Technology Data Exchange (ETDEWEB)

    Beugelsdijk, T.J.

    1990-01-01

    In October of 1989, molecular biologists throughout the world formally embarked on ultimately determining the set of genetic instructions for a human being. Called by some the Manhattan Project'' a molecular biology, pursuit of this goal is projected to require approximately 3000 man years of effort over a 15-year period. The Humane Genome Initiative is a worldwide research effort that has the goal of analyzing the structure of human deoxyribonucleic acid (DNA) and determining the location of all human genes. The Department of Energy (DOE) has designated three of its national laboratories as centers for the Human Genome Project. These are Los Alamos National Laboratory (LANL), Lawrence Livermore National Laboratory (LLNL), and Lawrence Berkeley Laboratory (LBL). These laboratories are currently working on different, but complementary technology development areas in support of the Human Genome Project. The robotics group at LANL is currently working at developing the technologies that address the problems associated with physical mapping. This article describes some of these problems and discusses some of the robotics approaches and engineering tolls applicable to their solution. 7 refs., 8 figs., 1 tab.

  11. A novel DNA sequence database for analyzing human demographic history.

    Science.gov (United States)

    Wall, Jeffrey D; Cox, Murray P; Mendez, Fernando L; Woerner, August; Severson, Tesa; Hammer, Michael F

    2008-08-01

    While there are now extensive databases of human genomic sequences from both private and public efforts to catalog human nucleotide variation, there are very few large-scale surveys designed for the purpose of analyzing human population history. Demographic inference from patterns of SNP variation in current large public databases is complicated by ascertainment biases associated with SNP discovery and the ways that populations and regions of the genome are sampled. Here, we present results from a resequencing survey of 40 independent intergenic regions on the autosomes and X chromosome comprising ~210 kb from each of 90 humans from six geographically diverse populations (i.e., a total of ~18.9 Mb). Unlike other public DNA sequence databases, we include multiple indigenous populations that serve as important reservoirs of human genetic diversity, such as the San of Namibia, the Biaka of the Central African Republic, and Melanesians from Papua New Guinea. In fact, only 20% of the SNPs that we find are contained in the HapMap database. We identify several key differences in patterns of variability in our database compared with other large public databases, including higher levels of nucleotide diversity within populations, greater levels of differentiation between populations, and significant differences in the frequency spectrum. Because variants at loci included in this database are less likely to be subject to ascertainment biases or linked to sites under selection, these data will be more useful for accurately reconstructing past changes in size and structure of human populations.

  12. Quantitative analysis of DNA methylation in the promoter region of the methylguanine-O(6) -DNA-methyltransferase gene by COBRA and subsequent native capillary gel electrophoresis.

    Science.gov (United States)

    Goedecke, Simon; Mühlisch, Jörg; Hempel, Georg; Frühwald, Michael C; Wünsch, Bernhard

    2015-12-01

    Along with histone modifications, RNA interference and delayed replication timing, DNA methylation belongs to the key processes in epigenetic regulation of gene expression. Therefore, reliable information about the methylation level of particular DNA fragments is of major interest. Herein the methylation level at two positions of the promoter region of the gene methylguanine-O(6) -DNA-Methyltransferase (MGMT) was investigated. Previously, it was demonstrated that the epigenetic status of this DNA region correlates with response to alkylating anticancer agents. An automated CGE method with LIF detection was established to separate the six DNA fragments resulting from combined bisulfite restriction analysis of the methylated and non-methylated MGMT promoter. In COBRA, the DNA was treated with bisulfite converting cytosine into uracil. During PCR uracil pairs with adenine, which changes the original recognition site of the restriction enzyme Taql. Artificial probes generated by mixing appropriate amounts of DNA after bisulfite treatment and PCR amplification were used for validation of the method. The methylation levels of these samples could be determined with high accuracy and precision. DNA samples prepared by mixing the corresponding clones first and then performing PCR amplification led to non-linear correlation between the corrected peak areas and the methylation levels. This effect is explained by slightly different PCR amplification of DNA with different sequences present in the mixture. The superiority of CGE over PAGE was clearly demonstrated. Finally, the established method was used to analyze the methylation levels of human brain tumor tissue samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. DNA synthesis determines the binding mode of the human mitochondrial single-stranded DNA-binding protein.

    Science.gov (United States)

    Morin, José A; Cerrón, Fernando; Jarillo, Javier; Beltran-Heredia, Elena; Ciesielski, Grzegorz L; Arias-Gonzalez, J Ricardo; Kaguni, Laurie S; Cao, Francisco J; Ibarra, Borja

    2017-07-07

    Single-stranded DNA-binding proteins (SSBs) play a key role in genome maintenance, binding and organizing single-stranded DNA (ssDNA) intermediates. Multimeric SSBs, such as the human mitochondrial SSB (HmtSSB), present multiple sites to interact with ssDNA, which has been shown in vitro to enable them to bind a variable number of single-stranded nucleotides depending on the salt and protein concentration. It has long been suggested that different binding modes might be used selectively for different functions. To study this possibility, we used optical tweezers to determine and compare the structure and energetics of long, individual HmtSSB-DNA complexes assembled on preformed ssDNA and on ssDNA generated gradually during 'in situ' DNA synthesis. We show that HmtSSB binds to preformed ssDNA in two major modes, depending on salt and protein concentration. However, when protein binding was coupled to strand-displacement DNA synthesis, only one of the two binding modes was observed under all experimental conditions. Our results reveal a key role for the gradual generation of ssDNA in modulating the binding mode of a multimeric SSB protein and consequently, in generating the appropriate nucleoprotein structure for DNA synthetic reactions required for genome maintenance. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  14. The relationship between DNA replication and human genome organization.

    Science.gov (United States)

    Necsulea, Anamaria; Guillet, Claire; Cadoret, Jean-Charles; Prioleau, Marie-Noëlle; Duret, Laurent

    2009-04-01

    Assessment of the impact of DNA replication on genome architecture in Eukaryotes has long been hampered by the scarcity of experimental data. Recent work, relying on computational predictions of origins of replication, suggested that replication might be a major determinant of gene organization in human (Huvet et al. 2007. Human gene organization driven by the coordination of replication and transcription. Genome Res. 17:1278-1285). Here, we address this question by analyzing the first large-scale data set of experimentally determined origins of replication in human: 283 origins identified in HeLa cells, in 1% of the genome covered by ENCODE regions (Cadoret et al. 2008. Genome-wide studies highlight indirect links between human replication origins and gene regulation. Proc Natl Acad Sci USA. 105:15837-15842). We show that origins of replication are not randomly distributed as they display significant overlap with promoter regions and CpG islands. The hypothesis of a selective pressure to avoid frontal collisions between replication and transcription polymerases is not supported by experimental data as we find no evidence for gene orientation bias in the proximity of origins of replication. The lack of a significant orientation bias remains manifest even when considering only genes expressed at a high rate, or in a wide number of tissues, and is not affected by the regional replication timing. Gene expression breadth does not appear to be correlated with the distance from the origins of replication. We conclude that the impact of DNA replication on human genome organization is considerably weaker than previously proposed.

  15. Apricot DNA as an indicator for persipan: detection and quantitation in marzipan using ligation-dependent probe amplification.

    Science.gov (United States)

    Luber, Florian; Demmel, Anja; Hosken, Anne; Busch, Ulrich; Engel, Karl-Heinz

    2012-06-13

    The confectionery ingredient marzipan is exclusively prepared from almond kernels and sugar. The potential use of apricot kernels, so-called persipan, is an important issue for the quality assessment of marzipan. Therefore, a ligation-dependent probe amplification (LPA) assay was developed that enables a specific and sensitive detection of apricot DNA, as an indicator for the presence of persipan. The limit of detection was determined to be 0.1% persipan in marzipan. The suitability of the method was confirmed by the analysis of 20 commercially available food samples. The integration of a Prunus -specific probe in the LPA assay as a reference allowed for the relative quantitation of persipan in marzipan. The limit of quantitation was determined to be 0.5% persipan in marzipan. The analysis of two self-prepared mixtures of marzipan and persipan demonstrated the applicability of the quantitation method at concentration levels of practical relevance for quality control.

  16. Optimized quantification of fragmented, free circulating DNA in human blood plasma using a calibrated duplex real-time PCR.

    Directory of Open Access Journals (Sweden)

    Martin Horlitz

    Full Text Available BACKGROUND: Duplex real-time PCR assays have been widely used to determine amounts and concentrations of free circulating DNA in human blood plasma samples. Circulatory plasma DNA is highly fragmented and hence a PCR-based determination of DNA concentration may be affected by the limited availability of full-length targets in the DNA sample. This leads to inaccuracies when counting PCR target copy numbers as whole genome equivalents. METHODOLOGY/PRINCIPAL FINDINGS: A model system was designed allowing for assessment of bias in a duplex real-time PCR research assay. We collected blood plasma samples from male donors in pools of 6 to 8 individuals. Circulatory plasma DNA was extracted and separated by agarose gel electrophoresis. Separated DNA was recovered from the gel in discrete size fractions and analyzed with different duplex real-time PCR Taqman assays detecting a Y chromosome-specific target and an autosomal target. The real-time PCR research assays used differed significantly in their ability to determine the correct copy number ratio of 0.5 between Y chromosome and autosome targets in DNA of male origin. Longer PCR targets did not amplify quantitatively in circulatory DNA, due to limited presence of full-length target sequence in the sample. CONCLUSIONS: PCR targets of the same small size are preferred over longer targets when comparing fractional circulatory DNA concentrations by real-time PCR. As an example, a DYS14/18S duplex real-time PCR research assay is presented that correctly measures the fractional concentration of male DNA in a male/female mixture of circulatory, fragmented DNA.

  17. The DNA methylation profile of activated human natural killer cells.

    Science.gov (United States)

    Wiencke, John K; Butler, Rondi; Hsuang, George; Eliot, Melissa; Kim, Stephanie; Sepulveda, Manuel A; Siegel, Derick; Houseman, E Andres; Kelsey, Karl T

    2016-05-03

    Natural killer (NK) cells are now recognized to exhibit characteristics akin to cells of the adaptive immune system. The generation of adaptive memory is linked to epigenetic reprogramming including alterations in DNA methylation. The study herein found reproducible genome wide DNA methylation changes associated with human NK cell activation. Activation led predominately to CpG hypomethylation (81% of significant loci). Bioinformatics analysis confirmed that non-coding and gene-associated differentially methylated sites (DMS) are enriched for immune related functions (i.e., immune cell activation). Known DNA methylation-regulated immune loci were also identified in activated NK cells (e.g., TNFA, LTA, IL13, CSF2). Twenty-one loci were designated high priority and further investigated as potential markers of NK activation. BHLHE40 was identified as a viable candidate for which a droplet digital PCR assay for demethylation was developed. The assay revealed high demethylation in activated NK cells and low demethylation in naïve NK, T- and B-cells. We conclude the NK cell methylome is plastic with potential for remodeling. The differentially methylated region signature of activated NKs revealed similarities with T cell activation, but also provided unique biomarker candidates of NK activation, which could be useful in epigenome-wide association studies to interrogate the role of NK subtypes in global methylation changes associated with exposures and/or disease states.

  18. Random-breakage mapping method applied to human DNA sequences

    Science.gov (United States)

    Lobrich, M.; Rydberg, B.; Cooper, P. K.; Chatterjee, A. (Principal Investigator)

    1996-01-01

    The random-breakage mapping method [Game et al. (1990) Nucleic Acids Res., 18, 4453-4461] was applied to DNA sequences in human fibroblasts. The methodology involves NotI restriction endonuclease digestion of DNA from irradiated calls, followed by pulsed-field gel electrophoresis, Southern blotting and hybridization with DNA probes recognizing the single copy sequences of interest. The Southern blots show a band for the unbroken restriction fragments and a smear below this band due to radiation induced random breaks. This smear pattern contains two discontinuities in intensity at positions that correspond to the distance of the hybridization site to each end of the restriction fragment. By analyzing the positions of those discontinuities we confirmed the previously mapped position of the probe DXS1327 within a NotI fragment on the X chromosome, thus demonstrating the validity of the technique. We were also able to position the probes D21S1 and D21S15 with respect to the ends of their corresponding NotI fragments on chromosome 21. A third chromosome 21 probe, D21S11, has previously been reported to be close to D21S1, although an uncertainty about a second possible location existed. Since both probes D21S1 and D21S11 hybridized to a single NotI fragment and yielded a similar smear pattern, this uncertainty is removed by the random-breakage mapping method.

  19. Extensive human DNA contamination in extracts from ancient dog bones and teeth.

    Science.gov (United States)

    Malmström, Helena; Storå, Jan; Dalén, Love; Holmlund, Gunilla; Götherström, Anders

    2005-10-01

    Ancient DNA (aDNA) sequences, especially those of human origin, are notoriously difficult to analyze due to molecular damage and exogenous DNA contamination. Relatively few systematic studies have focused on this problem. Here we investigate the extent and origin of human DNA contamination in the most frequently used sources for aDNA studies, that is, bones and teeth from museum collections. To distinguish contaminant DNA from authentic DNA we extracted DNA from dog (Canis familiaris) specimens. We monitored the presence of a 148-bp human-specific and a 152-bp dog-specific mitochondrial DNA (mtDNA) fragment in DNA extracts as well as in negative controls. The total number of human and dog template molecules were quantified using real-time polymerase chain reaction (PCR), and the sequences were characterized by amplicon cloning and sequencing. Although standard precautions to avoid contamination were taken, we found that all samples from the 29 dog specimens contained human DNA, often at levels exceeding the amount of authentic ancient dog DNA. The level of contaminating human DNA was also significantly higher in the dog extracts than in the negative controls, and an experimental setup indicated that this was not caused by the carrier effect. This suggests that the contaminating human DNA mainly originated from the dog bones rather than from laboratory procedures. When cloned, fragments within a contaminated PCR product generally displayed several different sequences, although one haplotype was often found in majority. This leads us to believe that recognized criteria for authenticating aDNA cannot separate contamination from ancient human DNA the way they are presently used.

  20. BLM–DNA2–RPA–MRN and EXO1–BLM–RPA–MRN constitute two DNA end resection machineries for human DNA break repair

    Science.gov (United States)

    Nimonkar, Amitabh V.; Genschel, Jochen; Kinoshita, Eri; Polaczek, Piotr; Campbell, Judith L.; Wyman, Claire; Modrich, Paul; Kowalczykowski, Stephen C.

    2011-01-01

    Repair of dsDNA breaks requires processing to produce 3′-terminated ssDNA. We biochemically reconstituted DNA end resection using purified human proteins: Bloom helicase (BLM); DNA2 helicase/nuclease; Exonuclease 1 (EXO1); the complex comprising MRE11, RAD50, and NBS1 (MRN); and Replication protein A (RPA). Resection occurs via two routes. In one, BLM and DNA2 physically and specifically interact to resect DNA in a process that is ATP-dependent and requires BLM helicase and DNA2 nuclease functions. RPA is essential for both DNA unwinding by BLM and enforcing 5′ → 3′ resection polarity by DNA2. MRN accelerates processing by recruiting BLM to the end. In the other, EXO1 resects the DNA and is stimulated by BLM, MRN, and RPA. BLM increases the affinity of EXO1 for ends, and MRN recruits and enhances the processivity of EXO1. Our results establish two of the core machineries that initiate recombinational DNA repair in human cells. PMID:21325134

  1. DNA Sequences Proximal to Human Mitochondrial DNA Deletion Breakpoints Prevalent in Human Disease Form G-quadruplexes, a Class of DNA Structures Inefficiently Unwound by the Mitochondrial Replicative Twinkle Helicase

    NARCIS (Netherlands)

    Bharti, S.K.; Sommers, J.A.; Zhou, J.; Kaplan, D.L.; Spelbrink, J.N.; Mergny, J.L.; Brosh, R.M., Jr.

    2014-01-01

    Mitochondrial DNA deletions are prominent in human genetic disorders, cancer, and aging. It is thought that stalling of the mitochondrial replication machinery during DNA synthesis is a prominent source of mitochondrial genome instability; however, the precise molecular determinants of defective

  2. Search for DNA damage by human alkyladenine DNA glycosylase involves early intercalation by an aromatic residue.

    Science.gov (United States)

    Hendershot, Jenna M; O'Brien, Patrick J

    2017-09-29

    DNA repair enzymes recognize and remove damaged bases that are embedded in the duplex. To gain access, most enzymes use nucleotide flipping, whereby the target nucleotide is rotated 180° into the active site. In human alkyladenine DNA glycosylase (AAG), the enzyme that initiates base excision repair of alkylated bases, the flipped-out nucleotide is stabilized by intercalation of the side chain of tyrosine 162 that replaces the lesion nucleobase. Previous kinetic studies provided evidence for the formation of a transient complex that precedes the stable flipped-out complex, but it is not clear how this complex differs from nonspecific complexes. We used site-directed mutagenesis and transient-kinetic approaches to investigate the timing of Tyr 162 intercalation for AAG. The tryptophan substitution (Y162W) appeared to be conservative, because the mutant protein retained a highly favorable equilibrium constant for flipping the 1, N 6 -ethenoadenine (ϵA) lesion, and the rate of N -glycosidic bond cleavage was identical to that of the wild-type enzyme. We assigned the tryptophan fluorescence signal from Y162W by removing two native tryptophan residues (W270A/W284A). Stopped-flow experiments then demonstrated that the change in tryptophan fluorescence of the Y162W mutant is extremely rapid upon binding to either damaged or undamaged DNA, much faster than the lesion-recognition and nucleotide flipping steps that were independently determined by monitoring the ϵA fluorescence. These observations suggest that intercalation by this aromatic residue is one of the earliest steps in the search for DNA damage and that this interaction is important for the progression of AAG from nonspecific searching to specific-recognition complexes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Boosting of DNA Vaccine-Elicited Gamma Interferon Responses in Humans by Exposure to Malaria Parasites

    National Research Council Canada - National Science Library

    Wang, Ruobing; Richie, Thomas L; Baraceros, Maria F; Rahardjo, Nancy; Gay, Tanya; Banania, Jo-Glenna; Charoenvit, Yupin; Epstein, Judith E; Luke, Thomas; Freilich, Daniel A; Norman, Jon; Hoffman, Stephen L

    2004-01-01

    A mixture of DNA plasmids expressing five Plasmodium falciparum pre-erythrocyte-stage antigens was administered with or without a DNA plasmid encoding human granulocyte-macrophage colony-stimulating factor (hGM-CSF...

  4. Data Acceptance Criteria for Standardized Human-Associated Fecal Source Identification Quantitative Real-Time PCR Methods.

    Science.gov (United States)

    Shanks, Orin C; Kelty, Catherine A; Oshiro, Robin; Haugland, Richard A; Madi, Tania; Brooks, Lauren; Field, Katharine G; Sivaganesan, Mano

    2016-05-01

    There is growing interest in the application of human-associated fecal source identification quantitative real-time PCR (qPCR) technologies for water quality management. The transition from a research tool to a standardized protocol requires a high degree of confidence in data quality across laboratories. Data quality is typically determined through a series of specifications that ensure good experimental practice and the absence of bias in the results due to DNA isolation and amplification interferences. However, there is currently a lack of consensus on how best to evaluate and interpret human fecal source identification qPCR experiments. This is, in part, due to the lack of standardized protocols and information on interlaboratory variability under conditions for data acceptance. The aim of this study is to provide users and reviewers with a complete series of conditions for data acceptance derived from a multiple laboratory data set using standardized procedures. To establish these benchmarks, data from HF183/BacR287 and HumM2 human-associated qPCR methods were generated across 14 laboratories. Each laboratory followed a standardized protocol utilizing the same lot of reference DNA materials, DNA isolation kits, amplification reagents, and test samples to generate comparable data. After removal of outliers, a nested analysis of variance (ANOVA) was used to establish proficiency metrics that include lab-to-lab, replicate testing within a lab, and random error for amplification inhibition and sample processing controls. Other data acceptance measurements included extraneous DNA contamination assessments (no-template and extraction blank controls) and calibration model performance (correlation coefficient, amplification efficiency, and lower limit of quantification). To demonstrate the implementation of the proposed standardized protocols and data acceptance criteria, comparable data from two additional laboratories were reviewed. The data acceptance criteria

  5. Quantitative and qualitative assessment of DNA extracted from saliva for its use in forensic identification.

    Science.gov (United States)

    Khare, Parul; Raj, Vineet; Chandra, Shaleen; Agarwal, Suraksha

    2014-05-01

    Saliva has long been known for its diagnostic value in several diseases. It also has a potential to be used in forensic science. The objective of this study is to compare the quantity and quality of DNA samples extracted from saliva with those extracted from blood in order to assess the feasibility of extracting sufficient DNA from saliva for its possible use in forensic identification. Blood and saliva samples were collected from 20 volunteers and DNA extraction was performed through Phenol Chloroform technique. The quantity and quality of isolated DNA was analyzed by spectrophotometery and the samples were then used to amplify short tandem repeat (STR) F13 using the polymerase chain reaction. Mean quantity of DNA obtained in saliva was 48.4 ± 8.2 μg/ml and in blood was 142.5 ± 45.9 μg/ml. Purity of DNA obtained as assessed by the ratio of optical density 260/280, was found to be optimal in 45% salivary samples while remaining showed minor contamination. Despite this positive F13 STR amplification was achieved in 75% of salivary DNA samples. Results of this study showed that saliva may prove to be a useful source of DNA for forensic purpose.

  6. Quantitative modeling of gene expression using DNA shape features of binding sites.

    Science.gov (United States)

    Peng, Pei-Chen; Sinha, Saurabh

    2016-07-27

    Prediction of gene expression levels driven by regulatory sequences is pivotal in genomic biology. A major focus in transcriptional regulation is sequence-to-expression modeling, which interprets the enhancer sequence based on transcription factor concentrations and DNA binding specificities and predicts precise gene expression levels in varying cellular contexts. Such models largely rely on the position weight matrix (PWM) model for DNA binding, and the effect of alternative models based on DNA shape remains unexplored. Here, we propose a statistical thermodynamics model of gene expression using DNA shape features of binding sites. We used rigorous methods to evaluate the fits of expression readouts of 37 enhancers regulating spatial gene expression patterns in Drosophila embryo, and show that DNA shape-based models perform arguably better than PWM-based models. We also observed DNA shape captures information complimentary to the PWM, in a way that is useful for expression modeling. Furthermore, we tested if combining shape and PWM-based features provides better predictions than using either binding model alone. Our work demonstrates that the increasingly popular DNA-binding models based on local DNA shape can be useful in sequence-to-expression modeling. It also provides a framework for future studies to predict gene expression better than with PWM models alone. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  7. Natural mummification of the human gut preserves bacteriophage DNA.

    Science.gov (United States)

    Santiago-Rodriguez, Tasha M; Fornaciari, Gino; Luciani, Stefania; Dowd, Scot E; Toranzos, Gary A; Marota, Isolina; Cano, Raul J

    2016-01-01

    The natural mummification process of the human gut represents a unique opportunity to study the resulting microbial community structure and composition. While results are providing insights into the preservation of bacteria, fungi, pathogenic eukaryotes and eukaryotic viruses, no studies have demonstrated that the process of natural mummification also results in the preservation of bacteriophage DNA. We characterized the gut microbiome of three pre-Columbian Andean mummies, namely FI3, FI9 and FI12, and found sequences homologous to viruses. From the sequences attributable to viruses, 50.4% (mummy FI3), 1.0% (mummy FI9) and 84.4% (mummy FI12) were homologous to bacteriophages. Sequences corresponding to the Siphoviridae, Myoviridae, Podoviridae and Microviridae families were identified. Predicted putative bacterial hosts corresponded mainly to the Firmicutes and Proteobacteria, and included Bacillus, Staphylococcus, Clostridium, Escherichia, Vibrio, Klebsiella, Pseudomonas and Yersinia. Predicted functional categories associated with bacteriophages showed a representation of structural, replication, integration and entry and lysis genes. The present study suggests that the natural mummification of the human gut results in the preservation of bacteriophage DNA, representing an opportunity to elucidate the ancient phageome and to hypothesize possible mechanisms of preservation. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. High expression of DNA methyltransferases in primary human medulloblastoma.

    Science.gov (United States)

    Pócza, T; Krenács, T; Turányi, E; Csáthy, J; Jakab, Z; Hauser, P

    2016-01-01

    Epigenetic alterations have been implicated in cancer development. DNA methylation modulates gene expression, which is catalyzed by DNA methyltransferases (DNMTs). The objective of our study was to evaluate expression of DNMTs in medulloblastoma and analyze its correlation with clinical features. Nuclear expression of DNMT1, DNMT3A and DNMT3B was analyzed in human primary medulloblastoma of 44 patients using immunohistochemistry. Correlation of expression of DNMT levels with classical histological subtypes, novel molecular subgroups and survival of patients was analyzed. Elevated expression of DNMT1, DNMT3A and DNMT3B was observed in 63.64%, 68.18% and 72.73% of all cases, respectively. None of them showed a correlation with classical histology or survival. Concerning molecular subtypes, significantly higher expression of DNMT1 was observed in the SHH group compared to non-SHH samples (p = 0.02), but without significant difference in DNMT3A or DNMT3B levels between any subtypes. In conclusion, DNMT1, DNMT3A and DNMT3B are highly expressed in human medulloblastoma samples, suggesting that promoter hypermethylation may play a role in medulloblastoma development. Demethylation of tumor suppressor gene promoters may be considered as a possible future target in therapy of medulloblastoma.

  9. [Human herpesvirus-8 DNA in patients with certain demyelinating disorders].

    Science.gov (United States)

    Olut, Ali Ilgin; Ozünlü, Haluk; Tan, Ersin; Kocagöz, Tanal

    2005-04-01

    Infectious etiology of the demyelinating diseases is an intensive matter of research. Among the suspected pathogens, herpesviruses had attracted particular attention because of their capacity to remain latent in nervous tissues, axonal transportation of some members within neurons, relapsing-remitting characteristic of the infections, and capability of inducing demyelination both in human host and animal models. Human herpesvirus-8 (HHV-8) is the least studied of this group even some of the HHV-8 related disorders such as HIV associated Castleman's disease, some lymphomas, monoclonal gammopathy of uncertain significance (MGUS), may be seen in patients with demyelinating conditions. The aim of this study was the investigation of a probable relationship between HHV-8 infection and certain demyelinating diseases. For this purpose, the presence of HHV-8 DNA has been investigated by polymerase chain reaction in the blood samples of 14 multiple sclerosis (MS), six chronic inflammatory demyelinizing polyneuropathy (CIDP), three Guillain-Barre syndrome (GBS), and one Miller-Fisher syndrome patients, together with 24 age- and sex-matched healthy subjects as control. As a result, one of MS, two of CIDP and all of the GBS patients were found HHV-8 DNA positive, whereas all the subjects in control group were negative. Although the interpretation of the results of this study does not seem to be possible owing to the limited number of patients, it emphasizes the need for larger scale, detailed studies on this subject since no other report dealing with this matter has been encountered in the literature.

  10. DNA repair proteins in cells of the human immune system; Le proteine della riparazione del DNA in cellule del sistema immunitario umano

    Energy Technology Data Exchange (ETDEWEB)

    Frasca, D.; Barattini, P.; Guidi, F.; Scarpaci, S. [ENEA, Sez. Tossicologia e Scienze Biomediche, Rome (Italy); Doria, G. [Rome Univ. Tor Vergata, Rome (Italy). Cattedra di Immunologia

    2001-02-01

    Human longevity depends on the efficiency of DNA repair mechanisms. In irradiated cells of the human immune system, the principal repair mechanism involves the DNA-Pk protein complex. [Italian] La durata della vita dipende dalla efficienza di meccanismi di riparazione del DNA. Nelle cellule del sistema immunitario umano danneggiate il principale meccanismo di riparazione coinvolge il complesso proteico DNA-PK.

  11. Regional quantitative histological variations in human oral mucosa.

    Science.gov (United States)

    Ciano, Joseph; Beatty, Brian Lee

    2015-03-01

    Oral mucosa demonstrates regional variations that reflect contact with food during mastication. Though known qualitatively, our aim was to quantitatively assess regions to establish a measurable baseline from which one could compare in pathological and comparative studies, in which the abrasiveness of diets may differ. We assessed variations in the epithelial-connective tissue junction (rete ridges counts), collagen organization within the lamina propria, and elastin composition of the lamina propria of 15 regions of the labial (buccal) gingiva, lingual gingiva, vestibule, and palate. All characteristics varied more between regions within the same individual than between individuals. Lingual gingiva had high rete ridges counts, high level of collagen organization, and moderate elastin composition compared to other regions. The labial gingiva had few rete ridges, high collagen organization, and low elastin. The vestibule had the fewest average of rete ridges, least organized collagen, and high elastin. The hard palate had the highest average of rete ridges, high collagen organization, and the lowest elastin content. The soft palate conversely had the smallest average of rete ridges, moderate collagen organization, and the highest elastin composition. Our results indicate that comparison of these quantitative histological differences is warranted only for collagen organization and elastin composition. Differences in rete ridges counts were not statistically significant. Most histological characteristics observed were not significantly different between dentulous and edentulous cadavers, and the group containing all individuals. An exception was the level of collagen fiber organization within the lamina propria, which was higher in most regions when teeth were present. © 2014 Wiley Periodicals, Inc.

  12. The Modified Human DNA Repair Enzyme O6-Methylguanine-DNA Methyltransferase Is a Negative Regulator of Estrogen Receptor-Mediated Transcription upon Alkylation DNA Damage

    OpenAIRE

    Teo, Alvin K. C.; Oh, Hue Kian; Ali, Rahmen B.; Li, Benjamin F. L.

    2001-01-01

    Cell proliferation requires precise control to prevent mutations from replication of (unrepaired) damaged DNA in cells exposed spontaneously to mutagens. Here we show that the modified human DNA repair enzyme O6-methylguanine-DNA methyltransferase (R-MGMT), formed from the suicidal repair of the mutagenic O6-alkylguanine (6RG) lesions by MGMT in the cells exposed to alkylating carcinogens, functions in such control by preventing the estrogen receptor (ER) from transcription activation that me...

  13. Quantitative proteomic analysis of post-translational modifications of human histones

    DEFF Research Database (Denmark)

    Beck, Hans Christian; Nielsen, Eva C; Matthiesen, Rune

    2006-01-01

    software for qualitative and quantitative proteomic analysis of histones extracted from human small cell lung cancer cells. A total of 32 acetylations, methylations, and ubiquitinations were located in the human histones H2A, H2B, H3, and H4, including seven novel modifications. An LC-MSMS-based method...... was applied in a quantitative proteomic study of the dose-response effect of the histone deacetylase inhibitor (HDACi) PXD101 on histone acetylation in human cell cultures. Triplicate LC-MSMS runs at six different HDACi concentrations demonstrated that PXD101 affects acetylation of histones H2A, H2B, H3...... by quantitative proteomics of histones from HDACi-treated cells were consistent with Western blot analysis of histone acetylation, cytotoxicity, and dose-dependent expression profiles of p21 and cyclin A2. This demonstrates that mass spectrometry-based quantitative proteomic analysis of post...

  14. Quantitation of Solifenacin in Human Plasma using a Specific and ...

    African Journals Online (AJOL)

    The blank human plasma batches were obtained free-of-charge from the Jordan National Blood Bank, Amman, ... was used (Peak nitrogen generator,. Scotland). The collision gas and curtain gas were set at 7 and ... The collision energy for solifenacin was 41 V and the collision cell exit potential was 11 V. Multiple reactions ...

  15. Quantitative assessment of human motion using video motion analysis

    Science.gov (United States)

    Probe, John D.

    1993-01-01

    In the study of the dynamics and kinematics of the human body a wide variety of technologies has been developed. Photogrammetric techniques are well documented and are known to provide reliable positional data from recorded images. Often these techniques are used in conjunction with cinematography and videography for analysis of planar motion, and to a lesser degree three-dimensional motion. Cinematography has been the most widely used medium for movement analysis. Excessive operating costs and the lag time required for film development, coupled with recent advances in video technology, have allowed video based motion analysis systems to emerge as a cost effective method of collecting and analyzing human movement. The Anthropometric and Biomechanics Lab at Johnson Space Center utilizes the video based Ariel Performance Analysis System (APAS) to develop data on shirtsleeved and space-suited human performance in order to plan efficient on-orbit intravehicular and extravehicular activities. APAS is a fully integrated system of hardware and software for biomechanics and the analysis of human performance and generalized motion measurement. Major components of the complete system include the video system, the AT compatible computer, and the proprietary software.

  16. Polycyclic aromatic hydrocarbon-DNA adducts in cervix of women infected with carcinogenic human papillomavirus types: An immunohistochemistry study

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, M. Margaret [Carcinogen-DNA Interactions Section, LCBG, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD (United States)], E-mail: prattm@mail.nih.gov; Sirajuddin, Paul; Poirier, Miriam C. [Carcinogen-DNA Interactions Section, LCBG, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD (United States); Schiffman, Mark [Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD (United States); Glass, Andrew G.; Scott, David R.; Rush, Brenda B. [Northwest Kaiser Permanente, Portland, OR (United States); Olivero, Ofelia A. [Carcinogen-DNA Interactions Section, LCBG, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD (United States); Castle, Philip E. [Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD (United States)

    2007-11-01

    Among women infected with carcinogenic human papillomavirus (HPV), there is a two- to five-fold increased risk of cervical precancer and cancer in women who smoke compared to those who do not smoke. Because tobacco smoke contains carcinogenic polycyclic aromatic hydrocarbons (PAHs), it was of interest to examine human cervical tissue for PAH-DNA adduct formation. Here, we measured PAH-DNA adduct formation in cervical biopsies collected in follow-up among women who tested positive for carcinogenic HPV at baseline. A semi-quantitative immunohistochemistry (IHC) method using antiserum elicited against DNA modified with r7,t8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) was used to measure nuclear PAH-DNA adduct formation. Cultured human cervical keratinocytes exposed to 0, 0.153, or 0.331 {mu}M BPDE showed dose-dependent increases in r7,t8,t9-trihydroxy-c-10-(N{sup 2}deoxyguanosyl)-7,8,9, 10-tetrahydro-benzo[a]pyrene (BPdG) adducts. For BPdG adduct analysis, paraffin-embedded keratinocytes were stained by IHC with analysis of nuclear color intensity by Automated Cellular Imaging System (ACIS) and, in parallel cultures, extracted DNA was assayed by quantitative BPDE-DNA chemiluminescence immunoassay (CIA). For paraffin-embedded samples from carcinogenic HPV-infected women, normal-appearing cervical squamous epithelium suitable for scoring was found in samples from 75 of the 114 individuals, including 29 cases of cervical precancer or cancer and 46 controls. With a lower limit of detection of 20 adducts/10{sup 8} nucleotides, detectable PAH-DNA adduct values ranged from 25 to 191/10{sup 8} nucleotides, with a median of 75/10{sup 8} nucleotides. PAH-DNA adduct values above 150/10{sup 8} nucleotides were found in eight samples, and in three samples adducts were non-detectable. There was no correlation between PAH-DNA adduct formation and either smoking or case status. Therefore, PAH-DNA adduct formation as measured by this methodology did not appear

  17. Comparison of Sensitivity and Quantitation between Microbead Dielectrophoresis-Based DNA Detection and Real-Time PCR

    Directory of Open Access Journals (Sweden)

    Michihiko Nakano

    2017-09-01

    Full Text Available In this study, we describe a microbead-based method using dielectrophoresis (DEP for the fast detection of DNA amplified by polymerase chain reaction (PCR. This electrical method measures the change in impedance caused by DEP-trapped microbeads to which biotinylated target DNA molecules are chemically attached. Using this method, measurements can be obtained within 20 min. Currently, real-time PCR is among the most sensitive methods available for the detection of target DNA, and is often used in the diagnosis of infectious diseases. We therefore compared the quantitation and sensitivity achieved by our method to those achieved with real-time PCR. We found that the microbead DEP-based method exhibited the same detection limit as real-time PCR, although its quantitative detection range was slightly narrower at 10–105 copies/reaction compared with 10–107 copies/reaction for real-time PCR. Whereas real-time PCR requires expensive and complex instruments, as well as expertise in primer design and experimental principles, our novel method is simple to use, inexpensive, and rapid. This method could potentially detect viral and other DNAs efficiently in combination with conventional PCR.

  18. Quantitative CrAssphage PCR Assays for Human Fecal ...

    Science.gov (United States)

    Environmental waters are monitored for fecal pollution to protect public health and water resources. Traditionally, general fecal indicator bacteria are used; however, they cannot distinguish human fecal waste from pollution from other animals. Recently, a novel bacteriophage, crAssphage, was discovered by metagenomic data mining and reported to be abundant in and closely associated with human fecal waste. To confirm bioinformatic predictions, 384 primer sets were designed along the length of the crAssphage genome. Based upon initial screening, two novel crAssphage qPCR assays (CPQ_056 and CPQ_064) were designed and evaluated in reference fecal samples and water matrices. The assays exhibited high specificities (98.6%) when tested against a large animal fecal reference library and were highly abundant in raw sewage and sewage impacted water samples. In addition, CPQ_056 and CPQ_064 assay performance was compared to HF183/BacR287 and HumM2 methods in paired experiments. Findings confirm viral crAssphage qPCR assays perform at a similar level to well established bacterial human-associated fecal source identification technologies. These new viral based assays could become important water quality management and research tools. To inform the public.

  19. Frequent detection of high human papillomavirus DNA loads in oral potentially malignant disorders.

    Science.gov (United States)

    Pierangeli, A; Cannella, F; Scagnolari, C; Gentile, M; Sciandra, I; Antonelli, G; Ciolfi, C; Russo, C; Palaia, G; Romeo, U; Polimeni, A

    2016-01-01

    Human papillomavirus (HPV) is estimated to be the cause of 40--80% of the squamous cell carcinoma of the oropharynx but only of a small fraction of the oral cavity cancers. The prevalence of oral HPV infection has significantly increased in the last decade, raising concerns about the role of HPV in progression of oral potentially malignant disorders (OPMD) toward squamous cell carcinomas. We sought to study HPV infection in patients with oral lesions, and in control individuals, using non-invasive and site-specific oral brushing and sensitive molecular methods. HPV DNA positivity and viral loads were evaluated in relation to patient data and clinical diagnosis. We enrolled 116 individuals attending Dental Clinics: 62 patients with benign oral lesions (e.g. fibromas, papillomatosis, ulcers) or OPMD (e.g. lichen, leukoplakia) and 54 controls. Oral cells were collected with Cytobrush and HPV-DNA was detected with quantitative real-time PCR for the more common high-risk (HR) and low-risk (LR) genotypes. HPV detection rate, percentage of HR HPVs and HPV-DNA loads (namely HPV16 and in particular, HPV18) were significantly higher in patients than in controls. Lichen planus cases had the highest HPV-positive rate (75.0%), hairy leukoplakia the lowest (33.3%). This study detected unexpectedly high rates of HPV infection in cells of the oral mucosa. The elevated HR HPV loads found in OPMD suggest the effectiveness of quantitative PCR in testing oral lesions. Prospective studies are needed to establish whether elevated viral loads represent a clinically useful marker of the risk of malignant progression. Copyright © 2015 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  20. Quantitative analysis of PPT1 interactome in human neuroblastoma cells

    Directory of Open Access Journals (Sweden)

    Enzo Scifo

    2015-09-01

    Full Text Available Mutations in the CLN1 gene that encodes Palmitoyl protein thioesterase 1 (PPT1 or CLN1, cause Infantile NCL (INCL, MIM#256730. PPT1 removes long fatty acid chains such as palmitate from modified cysteine residues of proteins. The data shown here result from isolated protein complexes from PPT1-expressing SH-SY5Y stable cells that were subjected to single step affinity purification coupled to mass spectrometry (AP-MS. Prior to the MS analysis, we utilised a modified filter-aided sample preparation (FASP protocol. Based on label free quantitative analysis of the data by SAINT, 23 PPT1 interacting partners (IP were identified. A dense connectivity in PPT1 network was further revealed by functional coupling and extended network analyses, linking it to mitochondrial ATP synthesis coupled protein transport and thioester biosynthetic process. Moreover, the terms: inhibition of organismal death, movement disorders and concentration of lipid were predicted to be altered in the PPT1 network. Data presented here are related to Scifo et al. (J. Proteomics, 123 (2015 42–53.

  1. A quasi-quantitative dual multiplexed immunoblot method to simultaneously analyze ATM and H2AX Phosphorylation in human peripheral blood mononuclear cells.

    Science.gov (United States)

    Bakkenist, Christopher J; Czambel, R Kenneth; Hershberger, Pamela A; Tawbi, Hussein; Beumer, Jan H; Schmitz, John C

    2015-01-01

    Pharmacologic inhibition of DNA repair may increase the efficacy of many cytotoxic cancer agents. Inhibitors of DNA repair enzymes including APE1, ATM, ATR, DNA-PK and PARP have been developed and the PARP inhibitor olaparib is the first-in-class approved in Europe and the USA for the treatment of advanced BRCA-mutated ovarian cancer. Sensitive pharmacodynamic (PD) biomarkers are needed to further evaluate the efficacy of inhibitors of DNA repair enzymes in clinical trials. ATM is a protein kinase that mediates cell-cycle checkpoint activation and DNA double-strand break repair. ATM kinase activation at DNA double-strand breaks (DSBs) is associated with intermolecular autophosphorylation on serine-1981. Exquisite sensitivity and high stoichiometry as well as facile extraction suggest that ATM serine-1981 phosphorylation may be a highly dynamic PD biomarker for both ATM kinase inhibitors and radiation- and chemotherapy-induced DSBs. Here we report the pre-clinical analytical validation and fit-for-purpose biomarker method validation of a quasi-quantitative dual multiplexed immunoblot method to simultaneously analyze ATM and H2AX phosphorylation in human peripheral blood mononuclear cells (PBMCs). We explore the dynamics of these phosphorylations in PBMCs exposed to chemotherapeutic agents and DNA repair inhibitors in vitro, and show that ATM serine-1981 phosphorylation is increased in PBMCs in sarcoma patients treated with DNA damaging chemotherapy.

  2. Environmental DNA COI barcoding for quantitative analysis of protists communities: A test using the Nebela collaris complex (Amoebozoa; Arcellinida; Hyalospheniidae).

    Science.gov (United States)

    Kosakyan, Anush; Mulot, Matthieu; Mitchell, Edward A D; Lara, Enrique

    2015-08-01

    Environmental DNA surveys are used for screening eukaryotic diversity. However, it is unclear how quantitative this approach is and to what extent results from environmental DNA studies can be used for ecological studies requiring quantitative data. Mitochondrial cytochrome oxidase (COI) is used for species-level taxonomic studies of testate amoebae and should allow assessing the community composition from environmental samples, thus bypassing biases due to morphological identification. We tested this using a COI clone library approach and focusing on the Nebela collaris complex. Comparisons with direct microscopy counts showed that the COI clone library diversity data matched the morphologically identified taxa, and that community composition estimates using the two approaches were similar. However, this correlation was improved when microscopy counts were corrected for biovolume. Higher correlation with biovolume-corrected community data suggests that COI clone library data matches the ratio of mitochondria and that within closely-related taxa the density of mitochondria per unit biovolume is approximately constant. Further developments of this metabarcoding approach including quantifying the mitochondrial density among closely-related taxa, experiments on other taxonomic groups and using high throughput sequencing should make if possible to quantitatively estimate community composition of different groups, which would be invaluable for microbial food webs studies. Copyright © 2015 Elsevier GmbH. All rights reserved.

  3. Real-time PCR assays for the quantitation of rDNA from apricot and other plant species in marzipan.

    Science.gov (United States)

    Haase, Ilka; Brüning, Philipp; Matissek, Reinhard; Fischer, Markus

    2013-04-10

    Marzipan or marzipan raw paste is a typical German sweet which is consumed directly or is used as an ingredient in the bakery industry/confectionery (e.g., in stollen) and as filling for chocolate candies. Almonds (blanched and pealed) and sugar are the only ingredients for marzipan production according to German food guidelines. Especially for the confectionery industry, the use of persipan, which contains apricot or peach kernels instead of almonds, is preferred due to its stronger aroma. In most of the companies, both raw pastes are produced, in most cases on the same production line, running the risk of an unintended cross contamination. Additionally, due to high almond market values, dilutions of marzipan with cheaper seeds may occur. Especially in the case of apricot and almond, the close relationship of both species is a challenge for the analysis. DNA based methods for the qualitative detection of apricot, peach, pea, bean, lupine, soy, cashew, pistachio, and chickpea in marzipan have recently been published. In this study, different quantitation strategies on the basis of real-time PCR have been evaluated and a relative quantitation method with a reference amplification product was shown to give the best results. As the real-time PCR is based on the high copy rDNA-cluster, even contaminations <1% can be reliably quantitated.

  4. The single-strand DNA binding activity of human PC4 preventsmutagenesis and killing by oxidative DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jen-Yeu; Sarker, Altaf Hossain; Cooper, Priscilla K.; Volkert, Michael R.

    2004-02-01

    Human positive cofactor 4 (PC4) is a transcriptional coactivator with a highly conserved single-strand DNA (ssDNA) binding domain of unknown function. We identified PC4 as a suppressor of the oxidative mutator phenotype of the Escherichia coli fpg mutY mutant and demonstrate that this suppression requires its ssDNA binding activity. Yeast mutants lacking their PC4 ortholog Sub1 are sensitive to hydrogen peroxide and exhibit spontaneous and peroxide induced hypermutability. PC4 expression suppresses the peroxide sensitivity of the yeast sub l{Delta} mutant, suggesting that the human protein has a similar function. A role for yeast and human proteins in DNA repair is suggested by the demonstration that Sub1 acts in a peroxide-resistance pathway involving Rad2 and by the physical interaction of PC4 with the human Rad2 homolog XPG. We show XPG recruits PC4 to a bubble-containing DNA substrate with resulting displacement of XPG and formation of a PC4-DNA complex. We discuss the possible requirement for PC4 in either global or transcription-coupled repair of oxidative DNA damage to mediate the release of XPG bound to its substrate.

  5. A Qualitative and Quantitative Assay to Study DNA/Drug Interaction ...

    African Journals Online (AJOL)

    247667, Uttaranchal, 3School of. Biotechnology ... Purpose: To explore the use of restriction inhibition assay (RIA) to study the binding specificity of some anticancer drugs. Methods: .... DNA along with each restriction enzyme alone was kept to ...

  6. Quantitative assessment of phytopathogenic fungi in various substrates using a DNA macroarray

    NARCIS (Netherlands)

    Lievens, B.; Brouwer, M.; Vanachter, A.C.R.C.; Lévesque, C.A.; Cammue, B.P.A.; Thomma, B.P.H.J.

    2005-01-01

    Detection, identification and quantification of plant pathogens are the cornerstones of preventive plant disease management. To detect multiple pathogens in a single assay, DNA array technology currently is the most suitable technique. However, for sensitive detection, polymerase chain reaction

  7. Prevalence of human papillomavirus and Epstein-Barr virus DNA in Chinese children with tonsillar and/or adenoidal hypertrophy.

    Science.gov (United States)

    Xue, Xiao-cheng; Chen, Xiao-ping; Yao, Wen-hao; Zhang, Yi; Sun, Guang-bin; Tan, Xue-jun

    2014-06-01

    Tonsillar and adenoidal hypertrophy are prevalent otolaryngologic disorders in children, but their pathogenesis is largely unknown. The presence of human papillomavirus (HPV) and Epstein-Barr virus (EBV) DNA in 146 tonsil and/or adenoid tissue specimens from 104 Chinese children with tonsillar and/or adenoidal hypertrophy were screened using flow-through hybridization gene-chip technology and real-time fluorescence-based quantitative PCR. Then, the relationships between the prevalence of the viruses and other clinical characteristics of tonsillar and/or adenoidal hypertrophy were analyzed. No patient had HPV DNA. EBV DNA was detected in 19/42 (45.2%) tonsil tissues and 72/104 (69.2%) adenoid tissue specimens (P hypertrophy. Adenoid tissues might more susceptible than tonsil tissues to EBV infection. In addition, EBV infection did not aggravate snoring in patients with tonsillar and/or adenoidal hypertrophy. © 2014 Wiley Periodicals, Inc.

  8. Strategy for the extraction of yeast DNA from artisan agave must for quantitative PCR analysis.

    Science.gov (United States)

    Kirchmayr, Manuel Reinhart; Segura-Garcia, Luis Eduardo; Flores-Berrios, Ericka Patricia; Gschaedler, Anne

    2011-11-01

    An efficient method for the direct extraction of yeast genomic DNA from agave must was developed. The optimized protocol, which was based on silica-adsorption of DNA on microcolumns, included an enzymatic cell wall degradation step followed by prolonged lysis with hot detergent. The resulting extracts were suitable templates for subsequent qPCR assays that quantified mixed yeast populations in artisan Mexican mezcal fermentations. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  9. A quantitative method for studying human arterial baroreflexes

    Science.gov (United States)

    Eckberg, Dwain L.; Fritsch, Janice M.; Goble, Ross L.

    1991-01-01

    A new system is described that delivers precise, stereotyped pressure changes to the human neck and elicits neurally-mediated heart rate changes. The centerpiece of this system is a Silastic chamber that is strapped to the anterior neck. This chamber is connected to a stepping-motor-controlled bellows assembly. A strain-gauge transducer measures the intensity of pressure changes. The entire system is controlled by microprocessors, and both stimuli and responses are displayed on a digital oscilloscope. The end-product of this system is a reproducible baroreceptor stimulus-cardiac response relation that can be recorded rapidly and safely in astronauts in space.

  10. A quantitative assay for lysosomal acidification rates in human osteoclasts

    DEFF Research Database (Denmark)

    Jensen, Vicki Kaiser; Nosjean, Olivier; Dziegiel, Morten Hanefeld

    2011-01-01

    lacunae. The electroneutrality of the lacunae is maintained by chloride transport through the chloride-proton antiporter chloride channel 7. Inhibition of either proton or chloride transport prevents bone resorption. The aims of this study were to validate the human osteoclastic microsome- based influx......M valinomycin increased the acid influx by 129%. Total abrogation of acid influx was observed using both H(+) and Cl(-) ionophores. Finally, investigation of the anion profile demonstrated that Cl(-) and Br(-) are the preferred anions for the transporter. In conclusion, the acid influx assay based on microsomes...

  11. ISFG: recommendations regarding the use of non-human (animal) DNA in forensic genetic investigations.

    Science.gov (United States)

    Linacre, A; Gusmão, L; Hecht, W; Hellmann, A P; Mayr, W R; Parson, W; Prinz, M; Schneider, P M; Morling, N

    2011-11-01

    The use of non-human DNA typing in forensic science investigations, and specifically that from animal DNA, is ever increasing. The term animal DNA in this document refers to animal species encountered in a forensic science examination but does not include human DNA. Non-human DNA may either be: the trade and possession of a species, or products derived from a species, which is contrary to legislation; as evidence where the crime is against a person or property; instances of animal cruelty; or where the animal is the offender. The first instance is addressed by determining the species present, and the other scenarios can often be addressed by assigning a DNA sample to a particular individual organism. Currently there is little standardization of methodologies used in the forensic analysis of animal DNA or in reporting styles. The recommendations in this document relate specifically to animal DNA that is integral to a forensic science investigation and are not relevant to the breeding of animals for commercial purposes. This DNA commission was formed out of discussions at the International Society for Forensic Genetics 23rd Congress in Buenos Aires to outline recommendations on the use of non-human DNA in a forensic science investigation. Due to the scope of non-human DNA typing that is possible, the remit of this commission is confined to animal DNA typing only. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  12. DNA Microarray Detection of 18 Important Human Blood Protozoan Species.

    Science.gov (United States)

    Chen, Mu-Xin; Ai, Lin; Chen, Jun-Hu; Feng, Xin-Yu; Chen, Shao-Hong; Cai, Yu-Chun; Lu, Yan; Zhou, Xiao-Nong; Chen, Jia-Xu; Hu, Wei

    2016-12-01

    Accurate detection of blood protozoa from clinical samples is important for diagnosis, treatment and control of related diseases. In this preliminary study, a novel DNA microarray system was assessed for the detection of Plasmodium, Leishmania, Trypanosoma, Toxoplasma gondii and Babesia in humans, animals, and vectors, in comparison with microscopy and PCR data. Developing a rapid, simple, and convenient detection method for protozoan detection is an urgent need. The microarray assay simultaneously identified 18 species of common blood protozoa based on the differences in respective target genes. A total of 20 specific primer pairs and 107 microarray probes were selected according to conserved regions which were designed to identify 18 species in 5 blood protozoan genera. The positive detection rate of the microarray assay was 91.78% (402/438). Sensitivity and specificity for blood protozoan detection ranged from 82.4% (95%CI: 65.9% ~ 98.8%) to 100.0% and 95.1% (95%CI: 93.2% ~ 97.0%) to 100.0%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) ranged from 20.0% (95%CI: 2.5% ~ 37.5%) to 100.0% and 96.8% (95%CI: 95.0% ~ 98.6%) to 100.0%, respectively. Youden index varied from 0.82 to 0.98. The detection limit of the DNA microarrays ranged from 200 to 500 copies/reaction, similar to PCR findings. The concordance rate between microarray data and DNA sequencing results was 100%. Overall, the newly developed microarray platform provides a convenient, highly accurate, and reliable clinical assay for the determination of blood protozoan species.

  13. Comparative Molecular Dynamics Studies of Human DNA Polymerase η

    Science.gov (United States)

    2015-01-01

    High-energy ultraviolet radiation damages DNA through the formation of cyclobutane pyrimidine dimers, which stall replication. When the lesion is a thymine–thymine dimer (TTD), human DNA polymerase η (Pol η) assists in resuming the replication process by inserting nucleotides opposite the damaged site. We performed extensive molecular dynamics (MD) simulations to investigate the structural and dynamical effects of four different Pol η complexes with or without a TTD and with either dATP or dGTP as the incoming base. No major differences in the overall structures and equilibrium dynamics were detected among the four systems, suggesting that the specificity of this enzyme is due predominantly to differences in local interactions in the binding regions. Analysis of the hydrogen-bonding interactions between the enzyme and the DNA and dNTP provided molecular-level insights. Specifically, the TTD was observed to engage in more hydrogen-bonding interactions with the enzyme than its undamaged counterpart of two normal thymines. The resulting greater rigidity and specific orientation of the TTD are consistent with the experimental observation of higher processivity and overall efficiency at TTD sites than at analogous sites with two normal thymines. The similarities between the systems containing dATP and dGTP are consistent with the experimental observation of relatively low fidelity with respect to the incoming base. Moreover, Q38 and R61, two strictly conserved amino acids across the Pol η family, were found to exhibit persistent hydrogen-bonding interactions with the TTD and cation-π interactions with the free base, respectively. Thus, these simulations provide molecular level insights into the basis for the selectivity and efficiency of this enzyme, as well as the roles of the two most strictly conserved residues. PMID:26562587

  14. Quantification and presence of human ancient DNA in burial place ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... useful for the improved ancient DNA extraction in anthropology and archeology. Key words: Ancient DNA, fossil bone, RT-PCR. INTRODUCTION. Ancient DNA research, defined as the retrieval and analysis of DNA sequences from various degraded biological source materials, has promoted many.

  15. Dynamic control of strand excision during human DNA mismatch repair.

    Science.gov (United States)

    Jeon, Yongmoon; Kim, Daehyung; Martín-López, Juana V; Lee, Ryanggeun; Oh, Jungsic; Hanne, Jeungphill; Fishel, Richard; Lee, Jong-Bong

    2016-03-22

    Mismatch repair (MMR) is activated by evolutionarily conserved MutS homologs (MSH) and MutL homologs (MLH/PMS). MSH recognizes mismatched nucleotides and form extremely stable sliding clamps that may be bound by MLH/PMS to ultimately authorize strand-specific excision starting at a distant 3'- or 5'-DNA scission. The mechanical processes associated with a complete MMR reaction remain enigmatic. The purified human (Homo sapien or Hs) 5'-MMR excision reaction requires the HsMSH2-HsMSH6 heterodimer, the 5' → 3' exonuclease HsEXOI, and the single-stranded binding heterotrimer HsRPA. The HsMLH1-HsPMS2 heterodimer substantially influences 5'-MMR excision in cell extracts but is not required in the purified system. Using real-time single-molecule imaging, we show that HsRPA or Escherichia coli EcSSB restricts HsEXOI excision activity on nicked or gapped DNA. HsMSH2-HsMSH6 activates HsEXOI by overcoming HsRPA/EcSSB inhibition and exploits multiple dynamic sliding clamps to increase tract length. Conversely, HsMLH1-HsPMS2 regulates tract length by controlling the number of excision complexes, providing a link to 5' MMR.

  16. CASA derived human sperm abnormalities: correlation with chromatin packing and DNA fragmentation

    National Research Council Canada - National Science Library

    Sivanarayana, T; Krishna, Ch Ravi; Prakash, G Jaya; Krishna, K Murali; Madan, K; Rani, B Sireesha; Sudhakar, G; Raju, G A. Rama

    2012-01-01

    The present study was undertaken to evaluate the effects of morphokinetic abnormalities of human spermatozoa on chromatin packing and DNA integrity and possible beneficial effects of sperm selection...

  17. Distinct kinetics of human DNA ligases I, IIIalpha, IIIbeta, and IV reveal direct DNA sensing ability and differential physiological functions in DNA repair

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xi; Ballin, Jeff D.; Della-Maria, Julie; Tsai, Miaw-Sheue; White, Elizabeth J.; Tomkinson, Alan E.; Wilson, Gerald M.

    2009-05-11

    The three human LIG genes encode polypeptides that catalyze phosphodiester bond formation during DNA replication, recombination and repair. While numerous studies have identified protein partners of the human DNA ligases (hLigs), there has been little characterization of the catalytic properties of these enzymes. In this study, we developed and optimized a fluorescence-based DNA ligation assay to characterize the activities of purified hLigs. Although hLigI joins DNA nicks, it has no detectable activity on linear duplex DNA substrates with short, cohesive single-strand ends. By contrast, hLigIII{beta} and the hLigIII{alpha}/XRCC1 and hLigIV/XRCC4 complexes are active on both nicked and linear duplex DNA substrates. Surprisingly, hLigIV/XRCC4, which is a key component of the major non-homologous end joining (NHEJ) pathway, is significantly less active than hLigIII on a linear duplex DNA substrate. Notably, hLigIV/XRCC4 molecules only catalyze a single ligation event in the absence or presence of ATP. The failure to catalyze subsequent ligation events reflects a defect in the enzyme-adenylation step of the next ligation reaction and suggests that, unless there is an in vivo mechanism to reactivate DNA ligase IV/XRCC4 following phosphodiester bond formation, the cellular NHEJ capacity will be determined by the number of adenylated DNA ligaseIV/XRCC4 molecules.

  18. Growth Inhibition and DNA Damage Induced by X-Phenols in Yeast: A Quantitative Structure-Activity Relationship Study.

    Science.gov (United States)

    Negritto, M Cristina; Valdez, Clarissa; Sharma, Jasmine; Rosenberg, Christa; Selassie, Cynthia R

    2017-12-31

    Phenolic compounds and their derivatives are ubiquitous constituents of numerous synthetic and natural chemicals that exist in the environment. Their toxicity is mostly attributed to their hydrophobicity and/or the formation of free radicals. In a continuation of the study of phenolic toxicity in a systematic manner, we have examined the biological responses of Saccharomyces cerevisiae to a series of mostly monosubstituted phenols utilizing a quantitative structure-activity relationship (QSAR) approach. The biological end points included a growth assay that determines the levels of growth inhibition induced by the phenols as well as a yeast deletion (DEL) assay that assesses the ability of X-phenols to induce DNA damage or DNA breaks. The QSAR analysis of cell growth patterns determined by IC50 and IC80 values indicates that toxicity is delineated by a hydrophobic, parabolic model. The DEL assay was then utilized to detect genomic deletions in yeast. The increase in the genotoxicity was enhanced by the electrophilicity of the phenolic substituents that were strong electron donors as well as by minimal hydrophobicity. The electrophilicities are represented by Brown's sigma plus values that are a variant of the Hammett sigma constants. A few mutant strains of genes involved in DNA repair were separately exposed to 2,6-di-tert-butyl-4-methyl-phenol (BHT) and butylated hydroxy anisole (BHA). They were subsequently screened for growth phenotypes. BHA-induced growth defects in most of the DNA repair null mutant strains, whereas BHT was unresponsive.

  19. Strategy for Extracting DNA from Clay Soil and Detecting a Specific Target Sequence via Selective Enrichment and Real-Time (Quantitative) PCR Amplification ▿

    Science.gov (United States)

    Yankson, Kweku K.; Steck, Todd R.

    2009-01-01

    We present a simple strategy for isolating and accurately enumerating target DNA from high-clay-content soils: desorption with buffers, an optional magnetic capture hybridization step, and quantitation via real-time PCR. With the developed technique, μg quantities of DNA were extracted from mg samples of pure kaolinite and a field clay soil. PMID:19633108

  20. Quantitation of Human Immunodeficiency Virus Type 1 (HIV-1) RNA in Cell-Free Cervicovaginal Secretions: Comparison of Reverse Transcription-PCR Amplification (AMPLICOR HIV-1 MONITOR 1.5) with Enhanced-Sensitivity Branched-DNA Assay (Quantiplex 3.0)

    Science.gov (United States)

    Si-Mohamed, Ali; Andreoletti, Laurent; Colombet, Isabelle; Carreno, Marie-Paule; Lopez, Gladys; Chatelier, Gilles; Kazatchkine, Michel D.; Belec, Laurent

    2001-01-01

    Two commercially available hypersensitive assays for human immunodeficiency virus type 1 (HIV-1) RNA quantitation, AMPLICOR HIV-1 Monitor Test 1.5 and Quantiplex HIV RNA 3.0, were compared to detect and quantify HIV-1 RNA in the cell-free fraction of cervicovaginal secretions collected by vaginal washing. Three panel specimens were used: pooled cervicovaginal secretions spiked with HIV-1 subtype A or HIV-1 subtype B and cervicovaginal lavages from HIV-positive and HIV-negative women. Compared to the AMPLICOR HIV-1 Monitor Test 1.5 assay, the Quantiplex HIV-1 3.0 assay yielded higher estimates of HIV-1 RNA concentrations in several tested samples spiked with HIV-1 RNA subtype A, as well as subtype B, particularly samples containing low amounts of HIV-1 RNA. The sensitivity and specificity of the AMPLICOR HIV-1 Monitor Test 1.5 assay were 93 and 100%, respectively; the sensitivity and specificity of the Quantiplex HIV RNA 3.0 assay were 97 and 50%, respectively. In conclusion, in quantifying HIV-1 RNA in cervicovaginal secretions, the Quantiplex HIV RNA 3.0 may lack specificity, and the AMPLICOR HIV-1 Monitor Test 1.5 assay, although highly specific, may lack sensitivity. PMID:11376034

  1. Allergenic Asteraceae in air particulate matter: quantitative DNA analysis of mugwort and ragweed.

    Science.gov (United States)

    Müller-Germann, I; Pickersgill, D A; Paulsen, H; Alberternst, B; Pöschl, U; Fröhlich-Nowoisky, J; Després, V R

    2017-01-01

    Mugwort (Artemisia vulgaris) and ragweed (Ambrosia artemisiifolia) are highly allergenic Asteraceae. They often cause pollen allergies in late summer and fall. While mugwort is native to Europe, ragweed reached Europe as a neophyte from North America about 150 years ago and continued spreading ever since. To understand possible relationships between the spread of ragweed, its abundance in air, and to judge possible health risks for the public, we quantified ragweed DNA in inhalable fine as well as in coarse air particulate matter. Mugwort was chosen for comparison, as it is closely related to ragweed and grows in similar, though mainly not identical, habitats but is native to Germany. The DNA quantification was performed on atmospheric aerosol samples collected over a period of 5 years in central Europe. The DNA concentrations were highest during the characteristic pollination periods but varied greatly between different years. In the inhalable fine particle fraction, ragweed exceeds the mugwort DNA concentration fivefold, while the coarse particle fraction, bearing intact pollen grains, contains more mugwort than ragweed DNA. The higher allergenic potential of ragweed might be linked to the humidity or long-range transport-induced bursting of ragweed pollen into smaller allergenic particles, which may reach the lower airways and cause more intense allergic reactions. Airborne ragweed DNA was detected also outside the local pollination periods, which can be explained by atmospheric long-range transport. Back-trajectory analyses indicate that the air masses containing ragweed DNA during winter had originated in regions with milder climate and large ragweed populations (Southern France, Carpathian Basin).

  2. A quantitative analysis of the structure of human sternum

    Directory of Open Access Journals (Sweden)

    Arbabi Azim

    2009-01-01

    Full Text Available An extensive study of the human sternum has been carried out to obtain estimates of the omnidirectional path-length distributions and structural parameters for trabeculation and marrow spaces. Data for sternum samples have been collected, using an object plane scanning microscope. These data have been used to produce the omnidirectional path-length distributions and values of structural parameters for the whole sternum. For a typical adult man the mean trabecular and marrow space path lengths are 224 and 1364 µm, respectively. The percentage bone volume is 13.8 and the surface to volume ratio is 190 cm. Data on the structural variations within the whole sternum are presented. They show a percentage difference in bone volume between the manubrium and the body of sternum of about 36%.

  3. Human DNA Extraction by Two Extraction Methods for Forensic Typification from Human Feces on FTA Paper

    Directory of Open Access Journals (Sweden)

    Shirleny Monserrat Sandoval-Arias

    2014-11-01

    Full Text Available The identification of suspects in criminal investigations has been facilitated since DNA test are executed on different samples. The application of this technology for forensic typification from human fecal samples still presents complications therefore this research evaluated two DNA extraction protocols with modifications to determine that of major efficiency. Organic extractions and extractions using the commercial kit “IQTM DNA Casework Sample Kit for Maxwell ® 16” on FTA portions of 4cm2 and 1cm2 impregnated with feces from the same individual were done to accomplish the objective. In all the assays the results were useful, however; the best forensic typification (by the electropherogram characteristics was obtained by using the commercial kit in an area of 1 cm2 of FTA paper impregnated in a 1:4 dilution.

  4. Quantitative Anatomy of the Trapezius Muscle in the Human Fetus.

    Science.gov (United States)

    Badura, Mateusz; Grzonkowska, Magdalena; Baumgart, Mariusz; Szpinda, Michał

    2016-01-01

    The trapezius muscle consists of three parts that are capable of functioning independently. Its superior part together with the levator scapulae and rhomboids elevate the shoulder, the middle part retracts the scapula, while the inferior part lowers the shoulder. The present study aimed to supplement numerical data and to provide growth dynamics of the trapezius in the human fetus. Using methods of anatomical dissection, digital image analysis (NIS Elements AR 3.0), and statistics (Student's t-test, regression analysis), we measured the length, the width and the surface area of the trapezius in 30 fetuses of both sexes (13™ k,17™ … ) aged 13-19 weeks. Neither sex nor laterality differences were found. All the studied parameters of the trapezius increased proportionately with age. The linear functions were computed as follows: y = -103.288 + 10.514 × age (r = 0.957) for total length of the trapezius muscle, y = -67.439 + 6.689 × age (r = 0.856) for length of its descending part, y = -8.493 + 1.033 × age (r = 0.53) for length of its transverse part, y = -27.545 + 2.802 × age (r = 0.791) for length of its ascending part, y = -19.970 + 2.505 × age (r = 0.875) for width of the trapezius muscle, and y = -2670.458 + 212.029 × age (r = 0.915) for its surface area. Neither sex nor laterality differences exist in the numerical data of the trapezius muscle in the human fetus. The descending part of trapezius is the longest, while its transverse part is the shortest. The growth dynamics of the fetal trapezius muscle follows proportionately.

  5. Normalizing genes for quantitative RT-PCR in differentiating human intestinal epithelial cells and adenocarcinomas of the colon.

    Science.gov (United States)

    Dydensborg, Anders Bondo; Herring, Elizabeth; Auclair, Joëlle; Tremblay, Eric; Beaulieu, Jean-Francois

    2006-05-01

    As for other mRNA measurement methods, quantitative RT-PCR results need to be normalized relative to stably expressed genes. Widely used normalizing genes include beta-actin and glyceraldehyde-3-phosphate dehydrogenase. It has, however, become clear that these and other normalizing genes can display modulated patterns of expression across tissue types and during complex cellular processes such as cell differentiation and cancer progression. Our objective was to set the basis for identifying normalizing genes that displayed stable expression during enterocytic differentiation and between healthy tissue and adenocarcinomas of the human colon. We thus identified novel potential normalizing genes using previously generated cDNA microarray data and examined the alterations of expression of two of these genes as well as seven commonly used normalizing genes during the enterocytic differentiation process and between matched pairs of resection margins and primary carcinomas of the human colon using real-time RT-PCR. We found that ribosomal phosphoprotein P0 was particularly stable in all intestinal epithelial cell extracts, thereby representing a particularly robust housekeeping reference gene for the assessment of gene expression during the human enterocytic differentiation process. On the other hand, beta-2-microglobulin generated the best score as a normalizing gene for comparing human colon primary carcinomas with their corresponding normal mucosa of the resection margin, although others were found to represent acceptable alternatives. In conclusion, we identified and characterized specific normalizing genes that should significantly improve quantitative mRNA studies related to both the differentiation process of the human intestinal epithelium and adenocarcinomas of the human colon. This approach should also be useful to validate normalizing genes in other intestinal contexts.

  6. Cloning and quantitative determination of the human Ca2+/calmodulin-dependent protein kinase II (CaMK II) isoforms in human beta cells.

    Science.gov (United States)

    Rochlitz, H; Voigt, A; Lankat-Buttgereit, B; Göke, B; Heimberg, H; Nauck, M A; Schiemann, U; Schatz, H; Pfeiffer, A F

    2000-04-01

    The Ca2+/calmodulin-dependent protein kinase II (CaMK II) is highly expressed in pancreatic islets and associated with insulin secretion vesicles. The suppression of CaMK II disturbs insulin secretion and insulin gene expression. There are four isoforms of CaMK II, alpha to delta, that are expressed from different genes in mammals. Our aim was to identify the isoforms of CaMK II expressed in human beta cells by molecular cloning from a human insulinoma cDNA library and to assess its distribution in humans. The previously unknown complete coding sequences of human CaMK IIbeta and the kinase domain of CaMK IIdelta were cloned from a human insulinoma cDNA library. Quantitative determination of CaMK II isoform mRNA was carried out in several tissues and beta cells purified by fluorescence activated cell sorting and compared to the housekeeping enzyme pyruvate dehydrogenase. We found CaMK IIbeta occurred in three splice variants and was highly expressed in endocrine tissues such as adrenals, pituitary and beta cells. Liver showed moderate expression but adipose tissue or lymphocytes had very low levels of CaMK IIbeta-mRNA. In human beta cells CaMK IIbeta and delta were expressed equally with pyruvate dehydrogenase whereas tenfold lower expression of CaMK IIgamma and no expression of CaMK IIalpha were found. Although CaMK IIdelta is ubiquitously expressed, CaMK IIbeta shows preferential expression in neuroendocrine tissues. In comparison with the expression of a key regulatory enzyme in glucose oxidation, pyruvate dehydrogenase, two of the four CaM kinases investigated are expressed at equally high levels, which supports an important role in beta-cell physiology. These results provide the basis for exploring the pathophysiological relevance of CaMK IIbeta in human diabetes.

  7. Identification of DNA methylation changes associated with human gastric cancer

    Directory of Open Access Journals (Sweden)

    Park Jung-Hoon

    2011-12-01

    Full Text Available Abstract Background Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult. Methods We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay in combination with a genome analyzer and a new normalization algorithm. Results We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs, transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those in the HOX and histone gene families. We also discovered long-range epigenetic silencing (LRES regions in gastric cancer tissue and identified several hypermethylated genes (MDM2, DYRK2, and LYZ within these regions. The methylation status of CGIs and gene annotation elements in metastatic lymph nodes was intermediate between normal and cancerous tissue, indicating that methylation of specific genes is gradually increased in cancerous tissue. Conclusions Our findings will provide valuable data for future analysis of CpG methylation patterns, useful markers for the diagnosis of stomach cancer, as well as a new analysis method for clinical epigenomics investigations.

  8. Optimized DNA electroporation for primary human T cell engineering.

    Science.gov (United States)

    Zhang, Zhang; Qiu, Shunfang; Zhang, Xiaopeng; Chen, Wei

    2018-01-30

    Effective gene-delivery systems for primary human T cell engineering are useful tools for both basic research and clinical immunotherapy applications. Pseudovirus-based systems and electro-transfection are the most popular strategies for genetic material transduction. Compared with viral-particle-mediated approaches, electro-transfection is theoretically safer, because it does not promote transgene integration into the host genome. Additionally, the simplicity and speed of the procedure increases the attractiveness of electroporation. Here, we developed and optimized an electro-transfection method for the production of engineered chimeric antigen receptor (CAR)-T cells. Stimulation of T cells had the greatest effect on their transfection, with stimulation of cells for up to 3 days substantially improving transfection efficiency. Additionally, the strength of the external electric field, input cell number, and the initial amount of DNA significantly affected transfection performance. The voltage applied during electroporation affected plasmid permeation and was negatively correlated with the number of viable cells after electroporation. Moreover, higher plasmid concentration increased the proportion of positively transfected cells, but decreased cell viability, and for single-activated cells, higher cell density enhanced their viability. We evaluated the effects of two clinically relevant factors, serum supplementation in the culture medium and cryopreservation immediately after the isolation of peripheral blood lymphocytes. Our findings showed that our protocol performed well using xeno-free cultured, fresh T cells, with application resulting in a lower but acceptable transfection efficiency of cells cultured with fetal bovine serum or thawed cells. Furthermore, we described an optimized procedure to generate CAR-T cells within 6 days and that exhibited cytotoxicity toward targeted cells. Our investigation of DNA electro-transfection for the use in human primary

  9. The human mitochondrial single-stranded DNA-binding protein displays distinct kinetics and thermodynamics of DNA binding and exchange.

    Science.gov (United States)

    Qian, Yufeng; Johnson, Kenneth A

    2017-08-04

    The human mitochondrial ssDNA-binding protein (mtSSB) is a homotetrameric protein, involved in mtDNA replication and maintenance. Although mtSSB is structurally similar to SSB from Escherichia coli (EcoSSB), it lacks the C-terminal disordered domain, and little is known about the biophysics of mtSSB-ssDNA interactions. Here, we characterized the kinetics and thermodynamics of mtSSB binding to ssDNA by equilibrium titrations and stopped-flow kinetic measurements. We show that the mtSSB tetramer can bind to ssDNA in two distinct binding modes: (SSB) 30 and (SSB) 60 , defined by DNA binding site sizes of 30 and 60 nucleotides, respectively. We found that the binding mode is modulated by magnesium ion and NaCl concentration, but unlike EcoSSB, the mtSSB does not show negative intersubunit cooperativity. Global fitting of both the equilibrium and kinetic data afforded estimates for the rate and equilibrium constants governing the formation of (SSB) 60 and (SSB) 30 complexes and for the transitions between the two binding modes. We found that the mtSSB tetramer binds to ssDNA with a rate constant near the diffusion limit (2 × 10 9 m -1 s -1 ) and that longer DNA (≥60 nucleotides) rapidly wraps around all four monomers, as revealed by FRET assays. We also show that the mtSSB tetramer can directly transfer from one ssDNA molecule to another via an intermediate with two DNA molecules bound to the mtSSB. In conclusion, our results indicate that human mtSSB shares many physicochemical properties with EcoSSB and that the differences may be explained by the lack of an acidic, disordered C-terminal tail in human mtSSB protein. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Hyperspectral and differential CARS microscopy for quantitative chemical imaging in human adipocytes

    OpenAIRE

    Di Napoli, Claudia; Pope, Iestyn; Masia, Francesco; Watson, Peter; Langbein, Wolfgang; Borri, Paola

    2014-01-01

    In this work, we demonstrate the applicability of coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy for quantitative chemical imaging of saturated and unsaturated lipids in human stem-cell derived adipocytes. We compare dual-frequency/differential CARS (D-CARS), which enables rapid imaging and simple data analysis, with broadband hyperspectral CARS microscopy analyzed using an unsupervised phase-retrieval and factorization method recently developed by us for quantitative chemica...

  11. Quantitative and multiplexed DNA methylation analysis using long-read single-molecule real-time bisulfite sequencing (SMRT-BS).

    Science.gov (United States)

    Yang, Yao; Sebra, Robert; Pullman, Benjamin S; Qiao, Wanqiong; Peter, Inga; Desnick, Robert J; Geyer, C Ronald; DeCoteau, John F; Scott, Stuart A

    2015-05-06

    DNA methylation has essential roles in transcriptional regulation, imprinting, X chromosome inactivation and other cellular processes, and aberrant CpG methylation is directly involved in the pathogenesis of human imprinting disorders and many cancers. To address the need for a quantitative and highly multiplexed bisulfite sequencing method with long read lengths for targeted CpG methylation analysis, we developed single-molecule real-time bisulfite sequencing (SMRT-BS). Optimized bisulfite conversion and PCR conditions enabled the amplification of DNA fragments up to ~1.5 kb, and subjecting overlapping 625-1491 bp amplicons to SMRT-BS indicated high reproducibility across all amplicon lengths (r=0.972) and low standard deviations (≤0.10) between individual CpG sites sequenced in triplicate. Higher variability in CpG methylation quantitation was correlated with reduced sequencing depth, particularly for intermediately methylated regions. SMRT-BS was validated by orthogonal bisulfite-based microarray (r=0.906; 42 CpG sites) and second generation sequencing (r=0.933; 174 CpG sites); however, longer SMRT-BS amplicons (>1.0 kb) had reduced, but very acceptable, correlation with both orthogonal methods (r=0.836-0.897 and r=0.892-0.927, respectively) compared to amplicons less than ~1.0 kb (r=0.940-0.951 and r=0.948-0.963, respectively). Multiplexing utility was assessed by simultaneously subjecting four distinct CpG island amplicons (702-866 bp; 325 CpGs) and 30 hematological malignancy cell lines to SMRT-BS (average depth of 110X), which identified a spectrum of highly quantitative methylation levels across all interrogated CpG sites and cell lines. SMRT-BS is a novel, accurate and cost-effective targeted CpG methylation method that is amenable to a high degree of multiplexing with minimal clonal PCR artifacts. Increased sequencing depth is necessary when interrogating longer amplicons (>1.0 kb) and the previously reported bisulfite sequencing PCR bias towards

  12. Quantitative determination of geranyl diphosphate levels in cultured human cells.

    Science.gov (United States)

    Holstein, Sarah A; Tong, Huaxiang; Kuder, Craig H; Hohl, Raymond J

    2009-11-01

    Geranyl diphosphate (GPP), a 10-carbon isoprenoid, is a key intermediate in the isoprenoid biosynthetic pathway. This pathway, in addition to leading to sterol synthesis, results in the synthesis of farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP), which serve as substrates for protein isoprenylation reactions. Basal levels of GPP in mammalian cells previously have been undetectable. Here we present a novel, sensitive, nonradioactive method which allows for measurement of GPP in mammalian cells. This methodology involves extraction of isoprenoids from cultured cells followed by enzymatic conjugation of GPP to a fluorescent dansylated-peptide via farnesyl transferase and quantification with high-performance liquid chromatography (HPLC). The lower limit of detection of GPP is 5 pg, or 0.015 pmol. Basal levels of GPP were determined in three human multiple myeloma cell lines (RPMI-8226, U266, H929). Treatment of cells with inhibitors of the isoprenoid biosynthetic pathway results in marked changes in GPP levels: the HMG-CoA reductase inhibitor lovastatin decreases GPP levels by over 50%, while the FPP synthase inhibitor zoledronic acid increases GPP levels 16- to 107-fold. This method also allows for the simultaneous measurement of GPP, FPP, and GGPP, thus leading to improved understanding of the pathway in a multitude of biological systems. Furthermore, as drugs targeting this pathway are developed, their biological activity can be more directly linked to effects on isoprenoid levels.

  13. DNA of Erythroid Origin Is Present in Human Plasma and Informs the Types of Anemia.

    Science.gov (United States)

    Lam, W K Jacky; Gai, Wanxia; Sun, Kun; Wong, Raymond S M; Chan, Rebecca W Y; Jiang, Peiyong; Chan, Natalie P H; Hui, Winnie W I; Chan, Anthony W H; Szeto, Cheuk-Chun; Ng, Siew C; Law, Man-Fai; Chan, K C Allen; Chiu, Rossa W K; Lo, Y M Dennis

    2017-10-01

    There is much interest in the tissue of origin of circulating DNA in plasma. Data generated using DNA methylation markers have suggested that hematopoietic cells of white cell lineages are important contributors to the circulating DNA pool. However, it is not known whether cells of the erythroid lineage would also release DNA into the plasma. Using high-resolution methylation profiles of erythroblasts and other tissue types, 3 genomic loci were found to be hypomethylated in erythroblasts but hypermethylated in other cell types. We developed digital PCR assays for measuring erythroid DNA using the differentially methylated region for each locus. Based on the methylation marker in the ferrochelatase gene, erythroid DNA represented a median of 30.1% of the plasma DNA of healthy subjects. In subjects with anemia of different etiologies, quantitative analysis of circulating erythroid DNA could reflect the erythropoietic activity in the bone marrow. For patients with reduced erythropoietic activity, as exemplified by aplastic anemia, the percentage of circulating erythroid DNA was decreased. For patients with increased but ineffective erythropoiesis, as exemplified by β-thalassemia major, the percentage was increased. In addition, the plasma concentration of erythroid DNA was found to correlate with treatment response in aplastic anemia and iron deficiency anemia. Plasma DNA analysis using digital PCR assays targeting the other 2 differentially methylated regions showed similar findings. Erythroid DNA is a hitherto unrecognized major component of the circulating DNA pool and is a noninvasive biomarker for differential diagnosis and monitoring of anemia. © 2017 American Association for Clinical Chemistry.

  14. Stem-loop structures of the repetitive DNA sequences located at human centromeres

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, G.; Garcia, A.E.; Ratliff, R.; Moyzis, R.K. [Los Alamos National Lab., NM (United States); Catasti, P.; Hong, Lin; Yau, P. [California Univ., Davis, CA (United States). Dept. of Biological Chemistry; Bradbury, E.M. [Los Alamos National Lab., NM (United States)]|[California Univ., Davis, CA (United States). Dept. of Biological Chemistry

    1993-09-01

    The presence of the highly conserved repetitive DNA sequences in the human centromeres argues for a special role of these sequences in their biological functions - most likely achieved by the formation of unusual structures. This prompted us to carry out quantitative one- and two-dimensional nuclear magnetic resonance (lD/2D NMR) spectroscopy to determine the structural properties of the human centromeric repeats, d(AATGG){sub n.d}(CCATT){sub n}. The studies on centromeric DNAs reveal that the complementary sequence, d(AATGG){sub n.d}(CCATT){sub n}, adopts the usual Watson-Crick B-DNA duplex and the pyrimidine-rich d(CCATT){sub n} strand is essentially a random coil. However, the purine-rich d(AATGG){sub n} strand is shown to adopt unusual stem-loop structures for repeat lengths, n=2,3,4, and 6. In addition to normal Watson-Crick A{center_dot}T pairs, the stem-loop structures are stabilized by mismatch A{center_dot}G and G{center_dot}G pairs in the stem and G-G-A stacking in the loop. Stem-loop structures of d(AATGG)n are independently verified by gel electrophoresis and nuclease digestion studies. Thermal melting studies show that the DNA repeats, d(AATGG){sub n}, are as stable as the corresponding Watson-Crick duplex d(AATGG){sub n.d}(CCATT){sub n}. Therefore, the sequence d(AATGG){sub n} can, indeed, nucleate a stem-loop structure at little free-energy cost and if, during mitosis, they are located on the chromosome surface they can provide specific recognition sites for kinetochore function.

  15. Compartmentalization and quantitation of protein in human milk.

    Science.gov (United States)

    Lönnerdal, B; Woodhouse, L R; Glazier, C

    1987-08-01

    Human milk protein was determined by three colorimetric methods and by Kjeldahl analysis. The distribution of nitrogen (N) and protein was determined within various milk compartments. Total N, whey, casein, nonprotein nitrogen (NPN), cell N and N in the fat fraction were analyzed by micro-Kjeldahl analysis after a series of centrifugation and ultracentrifugation separations. Fresh milk samples (colostrum, transitional milk and mature milk) were centrifuged at 500 X g to separate milk cells and at 5000 X g to skim the milk. Decelled milk and skimmed milk were ultracentrifuged at 189,000 X g to separate fat and casein micelles from whey. NPN was analyzed after trichloroacetic acid precipitation. Whole milk, decelled milk, skimmed milk and whey were analyzed for protein with the Lowry method, modified for fat-containing samples, the Bradford dye-binding assay (Bio-Rad) and the Pierce bicinchoninic acid (BCA) assay. Cell nitrogen had a tendency to be lower in mature milk than in colostrum. Colostrum contained only 6% casein protein, whereas mature milk contained 13%. Fat from skimming was lower in N than fat from ultracentrifugation. Average NPN levels were similar for milk from all three lactation periods, and constituted 10% of colostrum N and 25% of mature milk N. Protein determined by the Bio-Rad method on whole milk samples had the lowest variability (square root MSE) when correlated to Kjeldahl values. All three assays had lower variability when analyzing whey and skimmed milk than when analyzing whole milk. The Lowry method and the Bio-Rad method had low variability for whey and skimmed milk samples, but the Lowry method yielded analytical values closest to Kjeldahl protein values. The BCA method consistently overestimated Kjeldahl protein by 30%.

  16. Identification and cloning of endogenous retroviral sequences present in human DNA.

    OpenAIRE

    Martin, M. A.; Bryan, T; Rasheed, S; Khan, A S

    1981-01-01

    Using nonstringent annealing conditions and a 2.75-kilobase segment of cloned African green monkey DNA that specifically hybridizes to the proviruses of AKR ecotropic murine leukemia virus (MuLV) and baboon endogenous virus (BaEV) as a probe, we detected related sequences in three different preparations of human brain DNA fragments. The blot-hybridization pattern obtained with cleaved human DNA was similar to that previously reported for the interaction of MuLV cDNA and cleaved mouse DNA and ...

  17. Single-stranded DNA catenation mediated by human EVL and a type I topoisomerase

    OpenAIRE

    Takaku, Motoki; Takahashi, Daisuke; Machida, Shinichi; Ueno, Hiroyuki; Hosoya, Noriko; Ikawa, Shukuko; Miyagawa, Kiyoshi; Shibata, Takehiko; Kurumizaka, Hitoshi

    2010-01-01

    The human Ena/Vasp-like (EVL) protein is considered to be a bifunctional protein, involved in both actin remodeling and homologous recombination. In the present study, we found that human EVL forms heat-stable multimers of circular single-stranded DNA (ssDNA) molecules in the presence of a type I topoisomerase in vitro. An electron microscopic analysis revealed that the heat-stable ssDNA multimers formed by EVL and topoisomerase were ssDNA catemers. The ssDNA catenation did not occur when eit...

  18. Role of DNA Repair Factor Xeroderma Pigmentosum Protein Group C in Response to Replication Stress As Revealed by DNA Fragile Site Affinity Chromatography and Quantitative Proteomics.

    Science.gov (United States)

    Beresova, Lucie; Vesela, Eva; Chamrad, Ivo; Voller, Jiri; Yamada, Masayuki; Furst, Tomas; Lenobel, Rene; Chroma, Katarina; Gursky, Jan; Krizova, Katerina; Mistrik, Martin; Bartek, Jiri

    2016-12-02

    Replication stress (RS) fuels genomic instability and cancer development and may contribute to aging, raising the need to identify factors involved in cellular responses to such stress. Here, we present a strategy for identification of factors affecting the maintenance of common fragile sites (CFSs), which are genomic loci that are particularly sensitive to RS and suffer from increased breakage and rearrangements in tumors. A DNA probe designed to match the high flexibility island sequence typical for the commonly expressed CFS (FRA16D) was used as specific DNA affinity bait. Proteins significantly enriched at the FRA16D fragment under normal and replication stress conditions were identified using stable isotope labeling of amino acids in cell culture-based quantitative mass spectrometry. The identified proteins interacting with the FRA16D fragment included some known CFS stabilizers, thereby validating this screening approach. Among the hits from our screen so far not implicated in CFS maintenance, we chose Xeroderma pigmentosum protein group C (XPC) for further characterization. XPC is a key factor in the DNA repair pathway known as global genomic nucleotide excision repair (GG-NER), a mechanism whose several components were enriched at the FRA16D fragment in our screen. Functional experiments revealed defective checkpoint signaling and escape of DNA replication intermediates into mitosis and the next generation of XPC-depleted cells exposed to RS. Overall, our results provide insights into an unexpected biological role of XPC in response to replication stress and document the power of proteomics-based screening strategies to elucidate mechanisms of pathophysiological significance.

  19. New quantitative patterns of the growing trachea in human fetuses.

    Science.gov (United States)

    Szpinda, Michał; Daroszewski, Marcin; Szpinda, Anna; Woźniak, Alina; Wiśniewski, Marcin; Mila-Kierzenkowska, Celestyna; Baumgart, Mariusz; Paruszewska-Achtel, Monika

    2012-06-01

    Rapid progress in perinatal medicine has resulted in numerous tracheo-bronchial interventions on fetal and neonatal airways. The present study was performed to compile normative data for tracheal dimensions at varying gestational ages. Using anatomical dissection, digital image analysis (NIS-Elements BR 3.0) and statistical analysis (Wilcoxon signed-rank test, Student's t test, one-way ANOVA, post-hoc Bonferroni test, linear and nonlinear regression analysis) a range of the 4 variables (length in mm, middle external transverse diameter in mm, proximal internal cross-sectional area in mm², internal volume in mm³) for the trachea in 73 spontaneously aborted human fetuses (39 male, 34 female) aged 14-25 weeks was examined. No significant male-female differences were found (P>0.05). The length ranged from 10.37±2.15 to 26.54±0.26 mm as y=-65.098 + 28.796 × ln (Age) ±1.794 (R²=0.82). The middle external transverse diameter varied from 2.53±0.09 to 5.09±0.42 mm with the model y=-11.020 + 5.049 × ln (Age) ±0.330 (R²=0.81). The trachea indicated a proportional evolution because the middle external transverse diameter-to-length ratio was stable (0.23±0.03). The proximal internal cross-sectional area rose from 1.46±0.04 to 5.76±1.04 mm² as y=-3.562 + 0.352 × Age ±0.519 (R²=0.76). The internal volumetric growth from 11.89±2.49 to 119.63±4.95 mm³ generated the function y=-135.248 + 9.919 × Age ±10.478 (R²=0.86). The growth in both length and middle external transverse diameter of the trachea follows logarithmic functions, whereas growth of both its proximal internal cross-sectional area and internal volume follow linear functions. The length and middle external transverse diameter of the trachea develop proportionally to each other. The tracheal dimensions may be helpful in the prenatal diagnosis and monitoring of tracheal malformations and obstructive anomalies of the upper respiratory tract.

  20. Quantitative model of R-loop forming structures reveals a novel level of RNA–DNA interactome complexity

    Science.gov (United States)

    Wongsurawat, Thidathip; Jenjaroenpun, Piroon; Kwoh, Chee Keong; Kuznetsov, Vladimir

    2012-01-01

    R-loop is the structure co-transcriptionally formed between nascent RNA transcript and DNA template, leaving the non-transcribed DNA strand unpaired. This structure can be involved in the hyper-mutation and dsDNA breaks in mammalian immunoglobulin (Ig) genes, oncogenes and neurodegenerative disease related genes. R-loops have not been studied at the genome scale yet. To identify the R-loops, we developed a computational algorithm and mapped R-loop forming sequences (RLFS) onto 66 803 sequences defined by UCSC as ‘known’ genes. We found that ∼59% of these transcribed sequences contain at least one RLFS. We created R-loopDB (http://rloop.bii.a-star.edu.sg/), the database that collects all RLFS identified within over half of the human genes and links to the UCSC Genome Browser for information integration and visualisation across a variety of bioinformatics sources. We found that many oncogenes and tumour suppressors (e.g. Tp53, BRCA1, BRCA2, Kras and Ptprd) and neurodegenerative diseases related genes (e.g. ATM, Park2, Ptprd and GLDC) could be prone to significant R-loop formation. Our findings suggest that R-loops provide a novel level of RNA–DNA interactome complexity, playing key roles in gene expression controls, mutagenesis, recombination process, chromosomal rearrangement, alternative splicing, DNA-editing and epigenetic modifications. RLFSs could be used as a novel source of prospective therapeutic targets. PMID:22121227

  1. Quantitative model of R-loop forming structures reveals a novel level of RNA-DNA interactome complexity.

    Science.gov (United States)

    Wongsurawat, Thidathip; Jenjaroenpun, Piroon; Kwoh, Chee Keong; Kuznetsov, Vladimir

    2012-01-01

    R-loop is the structure co-transcriptionally formed between nascent RNA transcript and DNA template, leaving the non-transcribed DNA strand unpaired. This structure can be involved in the hyper-mutation and dsDNA breaks in mammalian immunoglobulin (Ig) genes, oncogenes and neurodegenerative disease related genes. R-loops have not been studied at the genome scale yet. To identify the R-loops, we developed a computational algorithm and mapped R-loop forming sequences (RLFS) onto 66,803 sequences defined by UCSC as 'known' genes. We found that ∼59% of these transcribed sequences contain at least one RLFS. We created R-loopDB (http://rloop.bii.a-star.edu.sg/), the database that collects all RLFS identified within over half of the human genes and links to the UCSC Genome Browser for information integration and visualisation across a variety of bioinformatics sources. We found that many oncogenes and tumour suppressors (e.g. Tp53, BRCA1, BRCA2, Kras and Ptprd) and neurodegenerative diseases related genes (e.g. ATM, Park2, Ptprd and GLDC) could be prone to significant R-loop formation. Our findings suggest that R-loops provide a novel level of RNA-DNA interactome complexity, playing key roles in gene expression controls, mutagenesis, recombination process, chromosomal rearrangement, alternative splicing, DNA-editing and epigenetic modifications. RLFSs could be used as a novel source of prospective therapeutic targets.

  2. A Qualitative and Quantitative Assay to Study DNA/Drug Interaction ...

    African Journals Online (AJOL)

    Purpose: To explore the use of restriction inhibition assay (RIA) to study the binding specificity of some anticancer drugs. Methods: A 448 bp DNA fragment derived from pBCKS+ plasmid (harboring the polylinker region with multiple restriction endonuclease sites) was used as a template for sequence selective inhibition of ...

  3. Quantitative studies of DNA methylation and gene expression in neuropsychiatric traits

    NARCIS (Netherlands)

    van Eijk, K.R.

    2014-01-01

    Research has shown that besides genes and environment, epigenetic factors are also playing a role in the development of traits and diseases. Epigenetic changes do not affect the underlying DNA sequence, but affect its structure and is thought to play a major role in regulation of gene expression.

  4. Qualitative and quantitative assessment of single fingerprints in forensic DNA analysis.

    Science.gov (United States)

    Ostojic, Lana; Klempner, Stacey A; Patel, Rosni A; Mitchell, Adele A; Axler-DiPerte, Grace L; Wurmbach, Elisa

    2014-11-01

    Fingerprints and touched items are important sources of DNA for STR profiling, since this evidence can be recovered in a wide variety of criminal offenses. However, there are some fundamental difficulties in working with these samples, including variability in quantity and quality of extracted DNA. In this study, we collected and analyzed over 700 fingerprints. We compared a commercially available extraction protocol (Zygem) to two methods developed in our laboratory, a simple one-tube protocol and a high sensitivity protocol (HighSens) that includes additional steps to concentrate and purify the DNA. The amplification protocols tested were AmpFLSTR® Identifiler® using either 28 or 31 amplification cycles, and Identifiler® Plus using 32 amplification cycles. We found that the HighSens and Zygem extraction methods were significantly better in their DNA yields than the one-tube method. Identifiler® Plus increased the quality of the STR profiles for the one-tube extraction significantly. However, this effect could not be verified for the other extraction methods. Furthermore, microscopic analysis of single fingerprints revealed that some individuals tended to shed more material than others onto glass slides. However, a dense deposition of skin flakes did not strongly correlate with a high quality STR profile. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Statistical assessment of DNA extraction reagent lot variability in real-time quantitative PCR

    Science.gov (United States)

    Bushon, R.N.; Kephart, C.M.; Koltun, G.F.; Francy, D.S.; Schaefer, F. W.; Lindquist, H.D. Alan

    2010-01-01

    Aims: The aim of this study was to evaluate the variability in lots of a DNA extraction kit using real-time PCR assays for Bacillus anthracis, Francisella tularensis and Vibrio cholerae. Methods and Results: Replicate aliquots of three bacteria were processed in duplicate with three different lots of a commercial DNA extraction kit. This experiment was repeated in triplicate. Results showed that cycle threshold values were statistically different among the different lots. Conclusions: Differences in DNA extraction reagent lots were found to be a significant source of variability for qPCR results. Steps should be taken to ensure the quality and consistency of reagents. Minimally, we propose that standard curves should be constructed for each new lot of extraction reagents, so that lot-to-lot variation is accounted for in data interpretation. Significance and Impact of the Study: This study highlights the importance of evaluating variability in DNA extraction procedures, especially when different reagent lots are used. Consideration of this variability in data interpretation should be an integral part of studies investigating environmental samples with unknown concentrations of organisms. ?? 2010 The Society for Applied Microbiology.

  6. LC-MS-MS quantitative analysis reveals the association between FTO and DNA methylation.

    Directory of Open Access Journals (Sweden)

    Yuting Zhu

    Full Text Available Fat mass and obesity-associated protein (FTO is α-ketoglutarate-dependent dioxygenase and responsible for demethylating N6-methyladenosine (m6A in mRNA, 3-methylthymine (m3T in single-stranded DNA (ssDNA and 3-methyluracil (m3U in single-stranded RNA (ssRNA. Its other function remains unknown but thousands of mammalian DNA show 5-methyl-2'-deoxycytidine (5mdC modification and 5mdC demethylases are required for mammalian energy homeostasis and fertility. Here, we aimed to confirm whether FTO proteins can demethylate 5mdC in DNA. However, we found that FTO exhibits no potent demethylation activity against 5mdC in vitro and in vivo by using liquid chromatography-tandem mass spectrometry (LC-MS-MS. The result showed FTO demethylase has the characteristics of high substrates specificity and selectivity. In addition, we also used immunofluorescence technique to demonstrate overexpression of wild type TET2, but not FTO and mutant TET2 in Hela cells results in higher levels of 5-hydroxymethyl-2'-deoxycytidine (5hmdC generated from 5mdC. In conclusion, our results not only reveal the enzymatic activity of FTO, but also may facilitate the future discovery of proteins involved in epigenetic modification function.

  7. LC-MS-MS quantitative analysis reveals the association between FTO and DNA methylation.

    Science.gov (United States)

    Zhu, Yuting; Zhou, Guangyu; Yu, Xuebin; Xu, Qiang; Wang, Kai; Xie, Dan; Yang, Qingkai; Wang, Lina

    2017-01-01

    Fat mass and obesity-associated protein (FTO) is α-ketoglutarate-dependent dioxygenase and responsible for demethylating N6-methyladenosine (m6A) in mRNA, 3-methylthymine (m3T) in single-stranded DNA (ssDNA) and 3-methyluracil (m3U) in single-stranded RNA (ssRNA). Its other function remains unknown but thousands of mammalian DNA show 5-methyl-2'-deoxycytidine (5mdC) modification and 5mdC demethylases are required for mammalian energy homeostasis and fertility. Here, we aimed to confirm whether FTO proteins can demethylate 5mdC in DNA. However, we found that FTO exhibits no potent demethylation activity against 5mdC in vitro and in vivo by using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The result showed FTO demethylase has the characteristics of high substrates specificity and selectivity. In addition, we also used immunofluorescence technique to demonstrate overexpression of wild type TET2, but not FTO and mutant TET2 in Hela cells results in higher levels of 5-hydroxymethyl-2'-deoxycytidine (5hmdC) generated from 5mdC. In conclusion, our results not only reveal the enzymatic activity of FTO, but also may facilitate the future discovery of proteins involved in epigenetic modification function.

  8. Characterization of noncoding regulatory DNA in the human genome.

    Science.gov (United States)

    Elkon, Ran; Agami, Reuven

    2017-08-08

    Genetic variants associated with common diseases are usually located in noncoding parts of the human genome. Delineation of the full repertoire of functional noncoding elements, together with efficient methods for probing their biological roles, is therefore of crucial importance. Over the past decade, DNA accessibility and various epigenetic modifications have been associated with regulatory functions. Mapping these features across the genome has enabled researchers to begin to document the full complement of putative regulatory elements. High-throughput reporter assays to probe the functions of regulatory regions have also been developed but these methods separate putative regulatory elements from the chromosome so that any effects of chromatin context and long-range regulatory interactions are lost. Definitive assignment of function(s) to putative cis-regulatory elements requires perturbation of these elements. Genome-editing technologies are now transforming our ability to perturb regulatory elements across entire genomes. Interpretation of high-throughput genetic screens that incorporate genome editors might enable the construction of an unbiased map of functional noncoding elements in the human genome.

  9. GHK and DNA: Resetting the Human Genome to Health

    Directory of Open Access Journals (Sweden)

    Loren Pickart

    2014-01-01

    Full Text Available During human aging there is an increase in the activity of inflammatory, cancer promoting, and tissue destructive genes plus a decrease in the activity of regenerative and reparative genes. The human blood tripeptide GHK possesses many positive effects but declines with age. It improves wound healing and tissue regeneration (skin, hair follicles, stomach and intestinal linings, and boney tissue, increases collagen and glycosaminoglycans, stimulates synthesis of decorin, increases angiogenesis, and nerve outgrowth, possesses antioxidant and anti-inflammatory effects, and increases cellular stemness and the secretion of trophic factors by mesenchymal stem cells. Recently, GHK has been found to reset genes of diseased cells from patients with cancer or COPD to a more healthy state. Cancer cells reset their programmed cell death system while COPD patients’ cells shut down tissue destructive genes and stimulate repair and remodeling activities. In this paper, we discuss GHK’s effect on genes that suppress fibrinogen synthesis, the insulin/insulin-like system, and cancer growth plus activation of genes that increase the ubiquitin-proteasome system, DNA repair, antioxidant systems, and healing by the TGF beta superfamily. A variety of methods and dosages to effectively use GHK to reset genes to a healthier state are also discussed.

  10. Capacitive DNA sensor for rapid and sensitive detection of whole genome human herpesvirus-1 dsDNA in serum.

    Science.gov (United States)

    Cheng, Cheng; Oueslati, Rania; Wu, Jayne; Chen, Jiangang; Eda, Shigetoshi

    2017-06-01

    This work presents a rapid, highly sensitive, low-cost, and specific capacitive DNA sensor for detection of whole genome human herpesvirus-1 DNA. This sensor is capable of direct DNA detection with a response time of 30 s, and it can be used to test standard buffer or serum samples. The sensing approach for DNA detection is based on alternating current (AC) electrokinetics. By applying an inhomogeneous AC electric field on sensor electrodes, positive dielectrophoresis is induced to accelerate DNA hybridization. The same applied AC signal also directly measures the hybridization of target with the probe on the sensor surface. Experiments are conducted to optimize the AC signal, as well as the buffers for probe immobilization and target DNA hybridization. The assay is highly sensitive and specific, with no response to human herpesvirus-2 DNA at 5 ng/mL and a LOD of 1.0 pg/mL (6.5 copies/μL or 10.7 aM) in standard buffer. When testing the double stranded (ds) DNA spiked in human serum samples, the sensor yields a LOD of 20.0 pg/mL (129.5 copies/μL or 0.21 femtomolar (fM)) in neat serum. In this work, the target is whole genome dsDNA, consequently the test can be performed without the use of enzyme or amplification, which considerably simplifies the sensor operation and is highly suitable for point of care disease diagnosis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Human NEIL3 is mainly a monofunctional DNA glycosylase removing spiroiminohydantoin and guanidinohydantoin

    OpenAIRE

    Krokeide, Silje Z.; Laerdahl, Jon K.; Salah, Medya; Luna, Luisa; Cederkvist, F. Henning; Fleming, Aaron M.; Burrows, Cynthia J.; Dalhus, Bjørn; Bjørås, Magnar

    2013-01-01

    Base excision repair is the major pathway for removal of oxidative DNA base damage. This pathway is initiated by DNA glycosylases, which recognize and excise damaged bases from DNA. In this work, we have purified the glycosylase domain (GD) of human DNA glycosylase NEIL3. The substrate specificity has been characterized and we have elucidated the catalytic mechanisms. GD NEIL3 excised the hydantoin lesions spiroiminodihydantoin (Sp) and guanidinohydantoin (Gh) in single-stranded (ss) and doub...

  12. PLASMID DNA DAMAGE CAUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITIN

    Science.gov (United States)

    PLASMID DNA DAMAGE CAOUSED BY METHYLATED ARSENICALS, ASCORBIC ACID AND HUMAN LIVER FERRITINABSTRACT Both dimethylarsinic acid (DMA(V)) and dimethylarsinous acid (DMA(III)) release iron from human liver ferritin (HLF) with or without the presence of ascorbic acid. ...

  13. Molecular cloning and characterization of human papilloma virus DNA derived from a laryngeal papilloma.

    Science.gov (United States)

    Gissmann, L; Diehl, V; Schultz-Coulon, H J; zur Hausen, H

    1982-01-01

    Papilloma virus DNA from a laryngeal papilloma was cloned in phage lambda L 47 and characterized after cleavage with different restriction enzymes. Hybridization with the DNAs of human papilloma virus types 1, 2, 3, 4, 5, and 8 showed no homology under stringent hybridization conditions. Human papilloma virus type 6 DNA, however, was partially identical to laryngeal papilloma virus DNA; different restriction enzyme fragments hybridizing with the other DNA were identified on each genome. The degree of homology was determined by reassociation kinetics to be 25%. According to the present nomenclature, laryngeal papilloma virus therefore represents a different type of human papilloma virus and is tentatively designated as human papilloma virus type 11. Sequences homologous to laryngeal papilloma virus DNA were also found in four of nine additional laryngeal papillomas. Attempt to detect homologous DNA in 12 carcinomas of the larynx were negative. Images PMID:6292500

  14. Human Papilloma Viral DNA Replicates as a Stable Episome in Cultured Epidermal Keratinocytes

    Science.gov (United States)

    Laporta, Robert F.; Taichman, Lorne B.

    1982-06-01

    Human papilloma virus (HPV) is poorly understood because systems for its growth in tissue culture have not been developed. We report here that cultured human epidermal keratinocytes could be infected with HPV from plantar warts and that the viral DNA persisted and replicated as a stable episome. There were 50-200 copies of viral DNA per cell and there was no evidence to indicate integration of viral DNA into the cellular genome. There was also no evidence to suggest that viral DNA underwent productive replication. We conclude that cultured human epidermal keratinocytes may be a model for the study of certain aspects of HPV biology.

  15. The DNA-binding box of human SPARTAN contributes to the targeting of Polη to DNA damage sites.

    Science.gov (United States)

    Toth, Agnes; Hegedus, Lili; Juhasz, Szilvia; Haracska, Lajos; Burkovics, Peter

    2017-01-01

    Inappropriate repair of UV-induced DNA damage results in human diseases such as Xeroderma pigmentosum (XP), which is associated with an extremely high risk of skin cancer. A variant form of XP is caused by the absence of Polη, which is normally able to bypass UV-induced DNA lesions in an error-free manner. However, Polη is highly error prone when replicating undamaged DNA and, thus, the regulation of the proper targeting of Polη is crucial for the prevention of mutagenesis and UV-induced cancer formation. Spartan is a novel regulator of the damage tolerance pathway, and its association with Ub-PCNA has a role in Polη targeting; however, our knowledge about its function is only rudimentary. Here, we describe a new biochemical property of purified human SPARTAN by showing that it is a DNA-binding protein. Using a DNA binding mutant, we provide in vivo evidence that DNA binding by SPARTAN regulates the targeting of Polη to damage sites after UV exposure, and this function contributes highly to its DNA-damage tolerance function. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Identification of some human pathogenic fungi using four DNA ...

    African Journals Online (AJOL)

    Stocks from pathogenic fungi isolated from infected areas on different patients, around Lagos-Nigeria were analysed using molecular methods (DNA extraction, PCR-RFLP and DNA sequencing). Four DNA extraction protocols were employed in the identification of the fungal isolates. Sixteen different fungal isolates were ...

  17. Blocking human contaminant DNA during PCR allows amplification of rare mammal species from sedimentary ancient DNA

    DEFF Research Database (Denmark)

    Boessenkool, Sanne; Epp, Laura S.; Haile, James Seymour

    2012-01-01

    Analyses of degraded DNA are typically hampered by contamination, especially when employing universal primers such as commonly used in environmental DNA studies. In addition to false-positive results, the amplification of contaminant DNA may cause false-negative results because of competition, or...

  18. Collaborating functions of BLM and DNA topoisomerase I in regulating human rDNA transcription

    Energy Technology Data Exchange (ETDEWEB)

    Grierson, Patrick M. [Department of Microbiology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210 (United States); Acharya, Samir, E-mail: samir.acharya@osumc.edu [Department of Microbiology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210 (United States); Groden, Joanna [Department of Microbiology, Immunology and Medical Genetics, The Ohio State University College of Medicine, Columbus, OH 43210 (United States)

    2013-03-15

    Bloom's syndrome (BS) is an inherited disorder caused by loss of function of the recQ-like BLM helicase. It is characterized clinically by severe growth retardation and cancer predisposition. BLM localizes to PML nuclear bodies and to the nucleolus; its deficiency results in increased intra- and inter-chromosomal recombination, including hyper-recombination of rDNA repeats. Our previous work has shown that BLM facilitates RNA polymerase I-mediated rRNA transcription in the nucleolus (Grierson et al., 2012 [18]). This study uses protein co-immunoprecipitation and in vitro transcription/translation (IVTT) to identify a direct interaction of DNA topoisomerase I with the C-terminus of BLM in the nucleolus. In vitro helicase assays demonstrate that DNA topoisomerase I stimulates BLM helicase activity on a nucleolar-relevant RNA:DNA hybrid, but has an insignificant effect on BLM helicase activity on a control DNA:DNA duplex substrate. Reciprocally, BLM enhances the DNA relaxation activity of DNA topoisomerase I on supercoiled DNA substrates. Our study suggests that BLM and DNA topoisomerase I function coordinately to modulate RNA:DNA hybrid formation as well as relaxation of DNA supercoils in the context of nucleolar transcription.

  19. Detection of human papillomavirus DNA by the hybrid capture assay

    Directory of Open Access Journals (Sweden)

    Carvalho Maria Odete O.

    2003-01-01

    Full Text Available Human Papillomavirus (HPV infection is the main cause of cervical cancers and cervical intraepithelial neoplasias (CIN worldwide. Consequently, it would be useful to evaluate HPV testing to screen for cervical cancer. Recently developed, the second-generation Hybrid Capture (HCA II test is a non-radioactive, relatively rapid, liquid hybridization assay designed to detect 18 HPV types, divided into high and low-risk groups. We evaluated 1055 women for HPV infection with the HCA II test. Five hundred and ten (48.3% of these women had HPV infection; 60 (11.8% had low cancer-risk HPV DNA; 269 (52.7% had high-risk HPV types and 181 (35.5% had both groups. Hence, 450 women (88.2% in this HPV-infected group had at least one high risk HPV type, and were therefore considered to be at high risk for cancer. Among the group with Papanicolaou (Pap test results, the overall prevalence of HPV DNA was 58.4%. Significant differences in HPV infection of the cervix were detected between Pap I (normal smears and Pap IV (carcinomas (p<0.0001. Values of HPV viral load obtained for Pap I and SILs were significantly different, with an upward trend (p<0.0001, suggesting a positive correlation between high viral load values and risk of SIL. Because of the high costs of the HCA II test, its use for routine cervical mass screening cannot be recommended in poor countries. Nevertheless, it is a useful tool when combined with cytology, diagnosing high-risk infections in apparently normal tissues. Use of this technique could help reduce the risk of cancer.

  20. Space Radiation Effects on Human Cells: Modeling DNA Breakage, DNA Damage Foci Distribution, Chromosomal Aberrations and Tissue Effects

    Science.gov (United States)

    Ponomarev, A. L.; Huff, J. L.; Cucinotta, F. A.

    2011-01-01

    Future long-tem space travel will face challenges from radiation concerns as the space environment poses health risk to humans in space from radiations with high biological efficiency and adverse post-flight long-term effects. Solar particles events may dramatically affect the crew performance, while Galactic Cosmic Rays will induce a chronic exposure to high-linear-energy-transfer (LET) particles. These types of radiation, not present on the ground level, can increase the probability of a fatal cancer later in astronaut life. No feasible shielding is possible from radiation in space, especially for the heavy ion component, as suggested solutions will require a dramatic increase in the mass of the mission. Our research group focuses on fundamental research and strategic analysis leading to better shielding design and to better understanding of the biological mechanisms of radiation damage. We present our recent effort to model DNA damage and tissue damage using computational models based on the physics of heavy ion radiation, DNA structure and DNA damage and repair in human cells. Our particular area of expertise include the clustered DNA damage from high-LET radiation, the visualization of DSBs (DNA double strand breaks) via DNA damage foci, image analysis and the statistics of the foci for different experimental situations, chromosomal aberration formation through DSB misrepair, the kinetics of DSB repair leading to a model-derived spectrum of chromosomal aberrations, and, finally, the simulation of human tissue and the pattern of apoptotic cell damage. This compendium of theoretical and experimental data sheds light on the complex nature of radiation interacting with human DNA, cells and tissues, which can lead to mutagenesis and carcinogenesis later in human life after the space mission.

  1. Human adipogenesis is associated with genome-wide DNA methylation and gene-expression changes

    DEFF Research Database (Denmark)

    Broholm, Christa; Olsson, Anders Henrik; Perfilyev, Alexander

    2016-01-01

    AIM: To define the genomic distribution and function of DNA methylation changes during human adipogenesis. METHODS: We isolated adipocyte-derived stem cells from 13 individuals and analyzed genome-wide DNA methylation and gene expression in cultured adipocyte-derived stem cells and mature adipocy...... for cell cycle and adipokine signaling. CONCLUSION: Human adipogenesis is associated with significant DNA methylation changes across the entire genome and may impact regulation of cell cycle and adipokine signaling....

  2. Resveratrol and ascorbic acid prevent DNA damage induced by cryopreservation in human semen.

    Science.gov (United States)

    Branco, Cátia S; Garcez, Márcia E; Pasqualotto, Fábio F; Erdtman, Bernardo; Salvador, Mirian

    2010-04-01

    Cryopreservation of human semen can cause DNA damages, which compromise the fertilization and normal embryo development. The present study showed that the antioxidant resveratrol prevents these damages both in fertile and infertile men. The addition of ascorbic acid before cryopreservation can reduce DNA damages only in infertile men. Although further studies are needed, the present work showed that resveratrol could be considered in human cryopreservation procedures to avoid/minimize DNA damages and preserve sperm integrity. Copyright 2009 Elsevier Inc. All rights reserved.

  3. No evidence of Neandertal mtDNA contribution to early modern humans.

    Directory of Open Access Journals (Sweden)

    David Serre

    2004-03-01

    Full Text Available The retrieval of mitochondrial DNA (mtDNA sequences from four Neandertal fossils from Germany, Russia, and Croatia has demonstrated that these individuals carried closely related mtDNAs that are not found among current humans. However, these results do not definitively resolve the question of a possible Neandertal contribution to the gene pool of modern humans since such a contribution might have been erased by genetic drift or by the continuous influx of modern human DNA into the Neandertal gene pool. A further concern is that if some Neandertals carried mtDNA sequences similar to contemporaneous humans, such sequences may be erroneously regarded as modern contaminations when retrieved from fossils. Here we address these issues by the analysis of 24 Neandertal and 40 early modern human remains. The biomolecular preservation of four Neandertals and of five early modern humans was good enough to suggest the preservation of DNA. All four Neandertals yielded mtDNA sequences similar to those previously determined from Neandertal individuals, whereas none of the five early modern humans contained such mtDNA sequences. In combination with current mtDNA data, this excludes any large genetic contribution by Neandertals to early modern humans, but does not rule out the possibility of a smaller contribution.

  4. Alternative DNA structure formation in the mutagenic human c-MYC promoter.

    Science.gov (United States)

    Del Mundo, Imee Marie A; Zewail-Foote, Maha; Kerwin, Sean M; Vasquez, Karen M

    2017-05-05

    Mutation 'hotspot' regions in the genome are susceptible to genetic instability, implicating them in diseases. These hotspots are not random and often co-localize with DNA sequences potentially capable of adopting alternative DNA structures (non-B DNA, e.g. H-DNA and G4-DNA), which have been identified as endogenous sources of genomic instability. There are regions that contain overlapping sequences that may form more than one non-B DNA structure. The extent to which one structure impacts the formation/stability of another, within the sequence, is not fully understood. To address this issue, we investigated the folding preferences of oligonucleotides from a chromosomal breakpoint hotspot in the human c-MYC oncogene containing both potential G4-forming and H-DNA-forming elements. We characterized the structures formed in the presence of G4-DNA-stabilizing K+ ions or H-DNA-stabilizing Mg2+ ions using multiple techniques. We found that under conditions favorable for H-DNA formation, a stable intramolecular triplex DNA structure predominated; whereas, under K+-rich, G4-DNA-forming conditions, a plurality of unfolded and folded species were present. Thus, within a limited region containing sequences with the potential to adopt multiple structures, only one structure predominates under a given condition. The predominance of H-DNA implicates this structure in the instability associated with the human c-MYC oncogene. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  5. Near-quantitative extraction of genomic DNA from various food-borne eubacteria

    Science.gov (United States)

    In this work we have tested a dozen commercial bacterial genomic DNA extraction methodologies on an average of 7.70E6 (± 9.05%), 4.77E8 (± 31.0%), and 5.93E8 (± 4.69%) colony forming units (CFU) associated with 3 cultures (n = 3) each of Brochothrix thermosphacta (Bt), Shigella sonnei (Ss), and Esch...

  6. A rapid and quantitative method to detect human circulating tumor cells in a preclinical animal model.

    Science.gov (United States)

    Tu, Shih-Hsin; Hsieh, Yi-Chen; Huang, Li-Chi; Lin, Chun-Yu; Hsu, Kai-Wen; Hsieh, Wen-Shyang; Chi, Wei-Ming; Lee, Chia-Hwa

    2017-06-23

    As cancer metastasis is the deadliest aspect of cancer, causing 90% of human deaths, evaluating the molecular mechanisms underlying this process is the major interest to those in the drug development field. Both therapeutic target identification and proof-of-concept experimentation in anti-cancer drug development require appropriate animal models, such as xenograft tumor transplantation in transgenic and knockout mice. In the progression of cancer metastasis, circulating tumor cells (CTCs) are the most critical factor in determining the prognosis of cancer patients. Several studies have demonstrated that measuring CTC-specific markers in a clinical setting (e.g., flow cytometry) can provide a current status of cancer development in patients. However, this useful technique has rarely been applied in the real-time monitoring of CTCs in preclinical animal models. In this study, we designed a rapid and reliable detection method by combining a bioluminescent in vivo imaging system (IVIS) and quantitative polymerase chain reaction (QPCR)-based analysis to measure CTCs in animal blood. Using the IVIS Spectrum CT System with 3D-imaging on orthotropic-developed breast-tumor-bearing mice. In this manuscript, we established a quick and reliable method for measuring CTCs in a preclinical animal mode. The key to this technique is the use of specific human and mouse GUS primers on DNA/RNA of mouse peripheral blood under an absolute qPCR system. First, the high sensitivity of cancer cell detection on IVIS was presented by measuring the luciferase carried MDA-MB-231 cells from 5 to 5x10(11) cell numbers with great correlation (R(2) = 0.999). Next, the MDA-MB-231 cell numbers injected by tail vein and their IVIS radiance signals were strongly corrected with qPCR-calculated copy numbers (R(2) > 0.99). Furthermore, by applying an orthotropic implantation animal model, we successfully distinguished xenograft tumor-bearing mice and control mice with a significant difference (p < 0

  7. Increased integrity of free circulating DNA in sera of patients with colorectal or periampullary cancer: direct quantitative PCR for ALU repeats.

    Science.gov (United States)

    Umetani, Naoyuki; Kim, Joseph; Hiramatsu, Suzanne; Reber, Howard A; Hines, Oscar J; Bilchik, Anton J; Hoon, Dave S B

    2006-06-01

    Cell-free DNA circulating in blood is a candidate biomarker for malignant tumors. Unlike uniformly truncated DNA released from apoptotic nondiseased cells, DNA released from dead cancer cells varies in size. We developed a novel method to measure the ratio of longer to shorter DNA fragments (DNA integrity) in serum as a potential biomarker for patients with colorectal cancer (CRC) or periampullary cancers (PACs). Sera from 32 patients with CRC (3 stage I, 14 stage II, 6 stage III, and 9 stage IV patients), 19 patients with PACs (2 stage I, 9 stage II, 1 stage III, and 7 stage IV patients), and 51 healthy volunteers were assessed by quantitative real-time PCR of ALU repeats (ALU-qPCR) with 2 sets of primers (115 and 247 bp) amplifying different lengths of DNA. We used serum directly as a template for ALU-qPCR without DNA purification. DNA integrity was determined as ratio of qPCR results of 247-bp ALU over 115-bp ALU. ALU-qPCR had a detection limit of 0.01 pg of DNA. Eliminating DNA purification reduced technical artifacts and reagent/labor costs. Serum DNA integrity was significantly increased for stage I/II and III/IV CRC and stage I/II and III/IV PACs (P = 0.002, P = 0.006, P = 0.022, and P integrity. DNA integrity is a potential serum biomarker for detection and evaluation of CRC and PACs.

  8. Investigation of DNA damage response and apoptotic gene methylation pattern in sporadic breast tumors using high throughput quantitative DNA methylation analysis technology

    Directory of Open Access Journals (Sweden)

    Prakash Neeraj

    2010-11-01

    Full Text Available Abstract Background- Sporadic breast cancer like many other cancers is proposed to be a manifestation of abnormal genetic and epigenetic changes. For the past decade our laboratory has identified genes involved in DNA damage response (DDR, apoptosis and immunesurvelliance pathways to influence sporadic breast cancer risk in north Indian population. Further to enhance our knowledge at the epigenetic level, we performed DNA methylation study involving 17 gene promoter regions belonging to DNA damage response (DDR and death receptor apoptotic pathway in 162 paired normal and cancerous breast tissues from 81 sporadic breast cancer patients, using a high throughput quantitative DNA methylation analysis technology. Results- The study identified five genes with statistically significant difference between normal and tumor tissues. Hypermethylation of DR5 (P = 0.001, DCR1 (P = 0.00001, DCR2 (P = 0.0000000005 and BRCA2 (P = 0.007 and hypomethylation of DR4 (P = 0.011 in sporadic breast tumor tissues suggested a weak/aberrant activation of the DDR/apoptotic pathway in breast tumorigenesis. Negative correlation was observed between methylation status and transcript expression levels for TRAIL, DR4, CASP8, ATM, CHEK2, BRCA1 and BRCA2 CpG sites. Categorization of the gene methylation with respect to the clinicopathological parameters showed an increase in aberrant methylation pattern in advanced tumors. These uncharacteristic methylation patterns corresponded with decreased death receptor apoptosis (P = 0.047 and DNA damage repair potential (P = 0.004 in advanced tumors. The observation of BRCA2 -26 G/A 5'UTR polymorphism concomitant with the presence of methylation in the promoter region was novel and emerged as a strong candidate for susceptibility to sporadic breast tumors. Conclusion- Our study indicates that methylation of DDR-apoptotic gene promoters in sporadic breast cancer is not a random phenomenon. Progressive epigenetic alterations in advancing

  9. Quantitative Mapping of Collagen Fiber Orientation in Non-glaucoma and Glaucoma Posterior Human Sclerae

    OpenAIRE

    Pijanka, Jacek K.; Coudrillier, B.; Ziegler, K; Sorensen, T.; Meek, Keith Michael Andrew; Nguyen, T. D.; Quigley, H A; Boote, Craig

    2012-01-01

    Purpose. The posterior sclera has a major biomechanical influence on the optic nerve head, and may therefore be important in glaucoma. Scleral material properties are influenced significantly by collagen fiber architecture. Here we quantitatively map fiber orientation in non-glaucoma and glaucoma posterior human sclerae.\\ud Methods. Wide-angle x-ray scattering quantified fiber orientation at 0.5-mm intervals across seven non-glaucoma post-mortem human sclerae, and five sclerae with glaucoma h...

  10. Discovery of human inversion polymorphisms by comparative analysis of human and chimpanzee DNA sequence assemblies.

    Directory of Open Access Journals (Sweden)

    2005-10-01

    Full Text Available With a draft genome-sequence assembly for the chimpanzee available, it is now possible to perform genome-wide analyses to identify, at a submicroscopic level, structural rearrangements that have occurred between chimpanzees and humans. The goal of this study was to investigate chromosomal regions that are inverted between the chimpanzee and human genomes. Using the net alignments for the builds of the human and chimpanzee genome assemblies, we identified a total of 1,576 putative regions of inverted orientation, covering more than 154 mega-bases of DNA. The DNA segments are distributed throughout the genome and range from 23 base pairs to 62 mega-bases in length. For the 66 inversions more than 25 kilobases (kb in length, 75% were flanked on one or both sides by (often unrelated segmental duplications. Using PCR and fluorescence in situ hybridization we experimentally validated 23 of 27 (85% semi-randomly chosen regions; the largest novel inversion confirmed was 4.3 mega-bases at human Chromosome 7p14. Gorilla was used as an out-group to assign ancestral status to the variants. All experimentally validated inversion regions were then assayed against a panel of human samples and three of the 23 (13% regions were found to be polymorphic in the human genome. These polymorphic inversions include 730 kb (at 7p22, 13 kb (at 7q11, and 1 kb (at 16q24 fragments with a 5%, 30%, and 48% minor allele frequency, respectively. Our results suggest that inversions are an important source of variation in primate genome evolution. The finding of at least three novel inversion polymorphisms in humans indicates this type of structural variation may be a more common feature of our genome than previously realized.

  11. Micro-ELISA for the quantitation of human urinary IgG

    DEFF Research Database (Denmark)

    Fomsgaard, A; Feldt-Rasmussen, B; Deckert, M

    1987-01-01

    range was 5-200 micrograms/l. The relative standard deviations within and between assays were 5 and 9%, respectively. Recovery of IgG added to urine was 100-102% (n = 12), and dilution of urine was linear. The assay range allowed for the quantitation of IgG in human urine samples, covering the clinical...

  12. Quantitative expression profiling of immune response genes in rainbow trout following infectious haematopoietic necrosis virus (IHNV) infection or DNA vaccination

    Science.gov (United States)

    Purcell, Maureen K.; Kurath, Gael; Garver, Kyle A.; Herwig, Russell P.; Winton, James R.

    2004-01-01

    Infectious haematopoietic necrosis virus (IHNV) is a well-studied virus of salmonid fishes. A highly efficacious DNA vaccine has been developed against this virus and studies have demonstrated that this vaccine induces both an early and transient non-specific anti-viral phase as well as long-term specific protection. The mechanisms of the early anti-viral phase are not known, but previous studies noted changes in Mx gene expression, suggesting a role for type I interferon. This study used quantitative real-time reverse transcriptase PCR methodology to compare expression changes over time of a number of cytokine or cytokine-related genes in the spleen of rainbow trout following injection with poly I:C, live IHNV, the IHNV DNA vaccine or a control plasmid encoding the non-antigenic luciferase gene. The target genes included Mx-1, viral haemorrhagic septicaemia virus induced gene 8 (Vig-8), TNF-α1, TNF-α2, IL-1β1, IL-8, TGF-β1 and Hsp70. Poly I:C stimulation induced several genes but the strongest and significant response was observed in the Mx-1 and Vig-8 genes. The live IHN virus induced a significant response in all genes examined except TGF-β1. The control plasmid construct and the IHNV DNA vaccine marginally induced a number of genes, but the main difference between these two groups was a statistically significant induction of the Mx-1 and Vig-8 genes by the IHNV vaccine only. The gene expression profiles elicited by the live virus and the IHNV DNA vaccine differed in a number of aspects but this study confirms the clear role for a type I interferon-like response in early anti-viral defence.

  13. Quantitative Single-letter Sequencing: a method for simultaneously monitoring numerous known allelic variants in single DNA samples

    Directory of Open Access Journals (Sweden)

    Duborjal Hervé

    2008-02-01

    Full Text Available Abstract Background Pathogens such as fungi, bacteria and especially viruses, are highly variable even within an individual host, intensifying the difficulty of distinguishing and accurately quantifying numerous allelic variants co-existing in a single nucleic acid sample. The majority of currently available techniques are based on real-time PCR or primer extension and often require multiplexing adjustments that impose a practical limitation of the number of alleles that can be monitored simultaneously at a single locus. Results Here, we describe a novel method that allows the simultaneous quantification of numerous allelic variants in a single reaction tube and without multiplexing. Quantitative Single-letter Sequencing (QSS begins with a single PCR amplification step using a pair of primers flanking the polymorphic region of interest. Next, PCR products are submitted to single-letter sequencing with a fluorescently-labelled primer located upstream of the polymorphic region. The resulting monochromatic electropherogram shows numerous specific diagnostic peaks, attributable to specific variants, signifying their presence/absence in the DNA sample. Moreover, peak fluorescence can be quantified and used to estimate the frequency of the corresponding variant in the DNA population. Using engineered allelic markers in the genome of Cauliflower mosaic virus, we reliably monitored six different viral genotypes in DNA extracted from infected plants. Evaluation of the intrinsic variance of this method, as applied to both artificial plasmid DNA mixes and viral genome populations, demonstrates that QSS is a robust and reliable method of detection and quantification for variants with a relative frequency of between 0.05 and 1. Conclusion This simple method is easily transferable to many other biological systems and questions, including those involving high throughput analysis, and can be performed in any laboratory since it does not require specialized

  14. Single-stranded DNA catenation mediated by human EVL and a type I topoisomerase

    Science.gov (United States)

    Takaku, Motoki; Takahashi, Daisuke; Machida, Shinichi; Ueno, Hiroyuki; Hosoya, Noriko; Ikawa, Shukuko; Miyagawa, Kiyoshi; Shibata, Takehiko; Kurumizaka, Hitoshi

    2010-01-01

    The human Ena/Vasp-like (EVL) protein is considered to be a bifunctional protein, involved in both actin remodeling and homologous recombination. In the present study, we found that human EVL forms heat-stable multimers of circular single-stranded DNA (ssDNA) molecules in the presence of a type I topoisomerase in vitro. An electron microscopic analysis revealed that the heat-stable ssDNA multimers formed by EVL and topoisomerase were ssDNA catemers. The ssDNA catenation did not occur when either EVL or topoisomerase was omitted from the reaction mixture. A deletion analysis revealed that the ssDNA catenation completely depended on the annealing activity of EVL. Human EVL was captured from a human cell extract by TOPO IIIα-conjugated beads, and the interaction between EVL and TOPO IIIα was confirmed by a surface plasmon resonance analysis. Purified TOPO IIIα catalyzed the ssDNA catenation with EVL as efficiently as the Escherichia coli topoisomerase I. Since the ssDNA cutting and rejoining reactions, which are the sub-steps of ssDNA catenation, may be an essential process in homologous recombination, EVL and TOPO IIIα may function in the processing of DNA intermediates formed during homologous recombination. PMID:20639531

  15. Primer in Genetics and Genomics, Article 3-Explaining Human Diversity: The Role of DNA.

    Science.gov (United States)

    Read, Catherine Y

    2017-05-01

    Genetic variation lays the foundation for diversity and enables humans to adapt to changing environments. The order of the nucleotides adenine, guanine, cytosine, and thymine on the deoxyribonucleic acid (DNA) molecules of the nuclear chromosomes and mitochondrial DNA (mtDNA) plays an important role in normal cell division, tissue development, and reproduction but is susceptible to alteration from a large number of random, inherited, or environmental events. Variations can range from a change in a single nucleotide to duplication of entire chromosomes. Single nucleotide polymorphisms are the major source of human heterogeneity. Other variations that can alter phenotypes and adversely impact growth, development, and health include copy number variations, aneuploidies, and structural alterations such as deletions, translocations, inversions, duplications, insertions, or mutations in mtDNA. In addition, DNA rearrangements in somatic cells underlie the uncontrolled cell growth found in cancer. This article explores the mechanisms by which variations in DNA arise and the impact those changes can have on human health.

  16. The effects of different maceration techniques on nuclear DNA amplification using human bone.

    Science.gov (United States)

    Lee, Esther J; Luedtke, Jennifer G; Allison, Jamie L; Arber, Carolyn E; Merriwether, D Andrew; Steadman, Dawnie Wolfe

    2010-07-01

    Forensic anthropologists routinely macerate human bone for the purposes of identity and trauma analysis, but the heat and chemical treatments used can destroy genetic evidence. As a follow-up to a previous study on nuclear DNA recovery that used pig ribs, this study utilizes human skeletal remains treated with various bone maceration techniques for nuclear DNA amplification using the standard Combined DNA Index System (CODIS) markers. DNA was extracted from 18 samples of human lower leg bones subjected to nine chemical and heat maceration techniques. Genotyping was carried out using the AmpFlSTR COfiler and AmpFlSTR Profiler Plus ID kits. Results showed that heat treatments via microwave or Biz/Na(2)CO(3) in sub-boiling water efficiently macerate bone and produce amplifiable nuclear DNA for genetic analysis. Long-term use of chemicals such as hydrogen peroxide is discouraged as it results in poor bone quality and has deleterious effects on DNA amplification.

  17. Characterizing the temporal dynamics of human papillomavirus DNA detectability using short-interval sampling.

    Science.gov (United States)

    Liu, Su-Hsun; Cummings, Derek A T; Zenilman, Jonathan M; Gravitt, Patti E; Brotman, Rebecca M

    2014-01-01

    Variable detection of human papillomavirus (HPV) DNA can result in misclassification of infection status, but the extent of misclassification has not been quantitatively evaluated. In 2005-2007, 33 women of ages 22 to 53 years self-collected vaginal swabs twice per week for 16 consecutive weeks. Each of the 955 swabs collected was tested for 37 HPV types/subtypes. Assuming that a woman's underlying infection status did not change over the short study period, biases in prevalence estimates obtained from single versus multiple swabs were calculated. Using event history analysis methods, time to recurrent gain and loss of at least one HPV type was determined, separately. Baseline any-type and high risk-type HPV prevalence was 60.6% and 24.2%, respectively. Cumulative any-HPV and high-risk HPV prevalence over the 16-week period was 84.8% and 60.6%, separately. Overall, there were 319 events of detection and 313 events of loss of detection. Median times to a recurrent detection and loss of detection were 11 and seven days, respectively. Neither vaginal sex nor condom use during follow-up was associated with recurrent viral detection or loss of detection. Assuming the cumulative 16-week prevalence reflects the true prevalence of infection, the baseline any-HPV prevalence underestimated infection status by 24.2%, with a bootstrapped mean of 20.2% [95% confidence interval (CI), 8.9%-29.6%]. These findings suggest that a substantial proportion of HPV-infected women are misclassified as being uninfected when using a single-time DNA measurement. Short-term variation in detectable HPV DNA needs to be considered while interpreting the natural history of infections using single samples collected at long intervals.

  18. Evaluation of two quantitative PCR assays using Bacteroidales and mitochondrial DNA markers for tracking dog fecal contamination in waterbodies.

    Science.gov (United States)

    Tambalo, Dinah D; Boa, Tyler; Liljebjelke, Karen; Yost, Christopher K

    2012-12-01

    This study describes a comparative performance evaluation of two qPCR assays targeting a dog-associated Bacteroidales 16S rRNA genetic marker (CanBac-UCD) and a dog mitochondrial DNA (mtDNA) marker. The same fecal and environmental samples were assayed for the two markers thereby allowing direct comparison. A wide range of non-target species including, human, pig, horse, deer, mountain goat, bison, caribou, and moose were tested. Marker persistence was also monitored in freshwater microcosms. Both markers were prevalent in the canine samples collected in Regina, Saskatchewan and Calgary, Alberta, Canada (91% and 98% sensitivity, respectively). The mtDNA marker was detected exclusively in the target species while the CanBac-UCD marker was detected in all the non-target species (31% specificity). The CanBac-UCD marker exhibited faster decay in freshwater microcosms. The markers were rarely detected in the water samples collected from dog parks in Calgary and in Regina as well as from waterbodies and sewage influents in Saskatchewan, indicating possibly low to negligible levels of dog fecal contamination in the sampling areas. Altogether, the results of this study support the utility of the dog mtDNA assay in detecting dog fecal contamination in waterbodies. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Vertically integrated analysis of human DNA. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Olson, M.

    1997-10-01

    This project has been oriented toward improving the vertical integration of the sequential steps associated with the large-scale analysis of human DNA. The central focus has been on an approach to the preparation of {open_quotes}sequence-ready{close_quotes} maps, which is referred to as multiple-complete-digest (MCD) mapping, primarily directed at cosmid clones. MCD mapping relies on simple experimental steps, supported by advanced image-analysis and map-assembly software, to produce extremely accurate restriction-site and clone-overlap maps. We believe that MCD mapping is one of the few high-resolution mapping systems that has the potential for high-level automation. Successful automation of this process would be a landmark event in genome analysis. Once other higher organisms, paving the way for cost-effective sequencing of these genomes. Critically, MCD mapping has the potential to provide built-in quality control for sequencing accuracy and to make possible a highly integrated end product even if there are large numbers of discontinuities in the actual sequence.

  20. The DNA sequence and biology of human chromosome 19

    Energy Technology Data Exchange (ETDEWEB)

    Grimwood, J; Gordon, L A; Olsen, A; Terry, A; Schmutz, J; Lamerdin, J; Hellsten, U; Goodstein, D; Couronne, O; Tran-Gyamfi, M

    2004-04-06

    Chromosome 19 has the highest gene density of all human chromosomes, more than double the genome-wide average. The large clustered gene families, corresponding high GC content, CpG islands and density of repetitive DNA indicate a chromosome rich in biological and evolutionary significance. Here we describe 55.8 million base pairs of highly accurate finished sequence representing 99.9% of the euchromatin portion of the chromosome. Manual curation of gene loci reveals 1,461 protein-coding genes and 321 pseudogenes. Among these are genes directly implicated in Mendelian disorders, including familial hypercholesterolemia and insulin-resistant diabetes. Nearly one quarter of these genes belong to tandemly arranged families, encompassing more than 25% of the chromosome. Comparative analyses show a fascinating picture of conservation and divergence, revealing large blocks of gene orthology with rodents, scattered regions with more recent gene family expansions and deletions, and segments of coding and non-coding conservation with the distant fish species Takifugu.

  1. Perspectives on the Holocene in Britain: human DNA

    Science.gov (United States)

    Evison, Martin P.

    1999-10-01

    Analysis of genetically-based variation in human populations has been possible for nearly a century. Recently, DNA sequence-based methods have begun to replace protein-based methods leading to a higher resolution, but more complex results. Patterns of gene distribution may be established with statistical reliability, but understanding them in terms of history is a process of interpretation; multi-disciplinary research is essential. A brief synopsis of the Holocene in Britain is presented, based on the genetic data , but with reference to archaeology, palaeoecology, ethnology and linguistics. The genetic history of Britain is a Holocene history. Patterns of gene distributions can be seen as the consequence of social processes and of selection. The major events are: the reoccupation of Britain in the Late Upper Palaeolithic/Early Mesolithic (c. 10,000-7,500 bp), social and demographic development during the Mesolithic (7,500-6,000 bp), and the Mesolithic-Neolithic transition (6,000-4,000 bp). Interpretations of the transition based on social interaction, intermarriage and minor genetic input are most consistent with the broad evidence. An extreme indigenist position is not supported.

  2. Complex forms of mitochondrial DNA in human B cells transformed by Epstein-Barr virus (EBV)

    DEFF Research Database (Denmark)

    Christiansen, Gunna; Christiansen, C; Zeuthen, J

    1983-01-01

    Human lymphocytes and lymphoid cell lines were analyzed for the presence of complex forms of mitochondrial DNA (mtDNA) by electron microscopy. A high frequency (9%-14.5%) of catenated dimers, circular dimers, or oligomers were found in samples from Epstein-Barr-virus-(EBV) transformed lymphoblast......Human lymphocytes and lymphoid cell lines were analyzed for the presence of complex forms of mitochondrial DNA (mtDNA) by electron microscopy. A high frequency (9%-14.5%) of catenated dimers, circular dimers, or oligomers were found in samples from Epstein-Barr-virus-(EBV) transformed...

  3. No increased sperm DNA fragmentation index in semen containing human papillomavirus or herpesvirus

    DEFF Research Database (Denmark)

    Kaspersen, Maja Døvling; Bungum, Mona; Fedder, Jens

    2013-01-01

    It remains unknown whether human papillomaviruses (HPVs) or human herpesviruses (HHVs) in semen affect sperm DNA integrity. We investigated whether the presence of these viruses in semen was associated with an elevated sperm DNA fragmentation index. Semen from 76 sperm donors was examined by a PCR......-based hybridization array that identifies all HHVs and 35 of the most common HPVs. Sperm DNA integrity was determined by the sperm chromatin structure assay. HPVs or HHVs, or both, were found in 57% of semen samples; however, sperm DNA fragmentation index was not increased in semen containing these viruses....

  4. Standardization and evaluation of a duplex real-time quantitative PCR for the detection of Leishmania infantum DNA: a sample quality control approach

    Directory of Open Access Journals (Sweden)

    Lays Adrianne Mendonça Trajano-Silva

    Full Text Available Abstract INTRODUCTION: Molecular techniques have been shown to be alternative methods for the accurate detection of infectious and parasitic diseases, such as the leishmaniases. The present study describes the optimization and evaluation of a duplex real-time quantitative PCR (qPCR protocol developed for the simultaneous detection of Leishmania infantum DNA and sample quality control. METHODS: After preliminary tests with the newly designed TaqMan® probes for the two targets ( L. infantum and glyceraldehyde 3-phosphate dehydrogenase (G3PD gene, the duplex qPCR protocol was optimized. For the evaluation of the standardized protocol, human blood samples were tested (n=68 and the results were compared to those obtained by reference diagnostic techniques. Statistical analyses included percentage agreement and the Kappa ( k coefficient. RESULTS: The detection limit of L. infantum DNA reached 2x10 2 fg (corresponding to ~1 parasite per µL of blood (ε: 93.9%. The percentage agreement obtained between the duplex VL qPCR and the reference techniques was individually obtained as follows: molecular: 88.3% ( k =0.666; 95% CI 0.437-0.894, good, and serological: 81.7% ( k =0.411; 95% CI 0.125-0.697, moderate. Between the reference techniques, the percentage agreement was 86.7% ( k =0.586; 95% CI 0.332-0.840, moderate. CONCLUSIONS: The new duplex VL qPCR protocol indicated good potential for the accurate, fast, and reliable detection of L. infantum DNA, when applied as a complement to the classical diagnostic tools already available, especially in health or research reference centers.

  5. DNA excision repair in cell extracts from human cell lines exhibiting hypersensitivity to DNA-damaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, J.; Keyse, S.M.; Lindahl, T.; Wood, R.D. (Imperial Cancer Research Fund, South Mimms, (United Kingdom))

    1991-07-01

    Whole cell extracts from human lymphoid cell lines can perform in vitro DNA repair synthesis in plasmids damaged by agents including UV or cis-diamminedichloroplatinum(II) (cis-DDP). Extracts from xeroderma pigmentosum (XP) cells are defective in repair synthesis. We have now studied in vitro DNA repair synthesis using extracts from lymphoblastoid cell lines representing four human hereditary syndromes with increased sensitivity to DNA-damaging agents. Extracts of cell lines from individuals with the sunlight-sensitive disorders dysplastic nevus syndrome or Cockayne's syndrome (complementation groups A and B) showed normal DNA repair synthesis in plasmids with UV photoproducts. This is consistent with in vivo measurements of the overall DNA repair capacity in such cell lines. A number of extracts were prepared from two cell lines representing the variant form of XP (XP-V). Half of the extracts prepared showed normal levels of in vitro DNA repair synthesis in plasmids containing UV lesions, but the remainder of the extracts from the same cell lines showed deficient repair synthesis, suggesting the possibility of an unusually labile excision repair protein in XP-V. Fanconi's anemia (FA) cells show cellular hypersensitivity to cross-linking agents including cis-DDP. Extracts from cell lines belonging to two different complementation groups of FA showed normal DNA repair synthesis in plasmids containing cis-DDP or UV adducts. Thus, there does not appear to be an overall excision repair defect in FA, but the data do not exclude a defect in the repair of interstrand DNA cross-links.

  6. Expanding the limits of human blood metabolite quantitation using NMR spectroscopy.

    Science.gov (United States)

    Nagana Gowda, G A; Gowda, Yashas N; Raftery, Daniel

    2015-01-06

    A current challenge in metabolomics is the reliable quantitation of many metabolites. Limited resolution and sensitivity combined with the challenges associated with unknown metabolite identification have restricted both the number and the quantitative accuracy of blood metabolites. Focused on alleviating this bottleneck in NMR-based metabolomics, investigations of pooled human serum combining an array of 1D/2D NMR experiments at 800 MHz, database searches, and spiking with authentic compounds enabled the identification of 67 blood metabolites. Many of these (∼1/3) are new compared with those reported previously as a part of the Human Serum Metabolome Database. In addition, considering both the high reproducibility and quantitative nature of NMR as well as the sensitivity of NMR chemical shifts to altered sample conditions, experimental protocols and comprehensive peak annotations are provided here as a guide for identification and quantitation of the new pool of blood metabolites for routine applications. Further, investigations focused on the evaluation of quantitation using organic solvents revealed a surprisingly poor performance for protein precipitation using acetonitrile. One-third of the detected metabolites were attenuated by 10-67% compared with methanol precipitation at the same solvent-to-serum ratio of 2:1 (v/v). Nearly 2/3 of the metabolites were further attenuated by up to 65% upon increasing the acetonitrile-to-serum ratio to 4:1 (v/v). These results, combined with the newly established identity for many unknown metabolites in the NMR spectrum, offer new avenues for human serum/plasma-based metabolomics. Further, the ability to quantitatively evaluate nearly 70 blood metabolites that represent numerous classes, including amino acids, organic acids, carbohydrates, and heterocyclic compounds, using a simple and highly reproducible analytical method such as NMR may potentially guide the evaluation of samples for analysis using mass spectrometry.

  7. Quantitation of Human Metallothionein Isoforms in Cells, Tissues, and Cerebrospinal Fluid by Mass Spectrometry.

    Science.gov (United States)

    Shabb, J B; Muhonen, W W; Mehus, A A

    2017-01-01

    Metallothioneins (MTs) are a family of small, highly conserved, cysteine-rich metal-binding proteins that are important for zinc and copper homeostasis, protection against oxidative stress, and buffering against toxic heavy metals. Individual human MT isoforms are candidate biomarkers for heavy metal toxicity, and selected cancers and neurodegenerative diseases. The similar antigenicity of human MT-1 and MT-2 isoforms precludes development of antibody-based assays for their individual quantitation. Metal-based MT quantitation methods do not directly measure MT isoforms. A bottom-up mass spectrometry-based approach solves these problems by exploiting the unique masses and chromatographic properties of the acetylated N-terminal tryptic peptides of MT isoforms. These unusually hydrophilic 20- to 21-residue peptides contain five invariant cysteines. Strong cation exchange chromatography separates them from bulk internal tryptic peptides. Reversed-phase chromatography further separates them from more hydrophobic peptides of similar mass. Absolute quantitation is obtained by adding MT peptide standards alkylated with (15)N-iodoacetamide to biological samples alkylated with (14)N-iodoacetamide. Accurate quantitation is enhanced by dimethyl sulfide treatment to reverse oxidation of the N-terminal methionine. Originally optimized for measuring MT isoforms in cell lines, the method has been adapted to quantify MT isoforms in brain tissue and cerebrospinal fluid. The method can also be adapted for relative quantitation of MT isoforms between matched biological samples. It cannot be used to measure human MT-4 because of an arginine at position 4. Except for this type of limitation, the method is applicable to MT quantitation in many other species. © 2017 Elsevier Inc. All rights reserved.

  8. Induction of a mutant phenotype in human repair proficient cells after overexpression of a mutated human DNA repair gene.

    NARCIS (Netherlands)

    P.B.G.M. Belt; M.F. van Oostenrijk; H. Odijk (Hanny); J.H.J. Hoeijmakers (Jan); C.M.P. Backendorf (Claude)

    1991-01-01

    textabstractAntisense and mutated cDNA of the human excision repair gene ERCC-1 were overexpressed in repair efficient HeLa cells by means of an Epstein-Barr-virus derived CDNA expression vector. Whereas antisense RNA did not influence the survival of the transfected cells, a mutated cDNA generating

  9. Early Gene Expression in Wounded Human Keratinocytes Revealed by DNA Microarray Analysis

    Directory of Open Access Journals (Sweden)

    Pascal Barbry

    2006-04-01

    Full Text Available Wound healing involves several steps: spreading of the cells, migration and proliferation. We have profiled gene expression during the early events of wound healing in normal human keratinocytes with a home-made DNA microarray containing about 1000 relevant human probes. An original wounding machine was used, that allows the wounding of up to 40% of the surface of a confluent monolayer of cultured cells grown on a Petri dish (compared with 5% with a classical ‘scratch’ method. The two aims of the present study were: (a to validate a limited number of genes by comparing the expression levels obtained with this technique with those found in the literature; (b to combine the use of the wounding machine with DNA microarray analysis for large-scale detection of the molecular events triggered during the early stages of the wound-healing process. The time-courses of RNA expression observed at 0.5, 1.5, 3, 6 and 15 h after wounding for genes such as c-Fos, c-Jun, Egr1, the plasminogen activator PLAU (uPA and the signal transducer and transcription activator STAT3, were consistent with previously published data. This suggests that our methodologies are able to perform quantitative measurement of gene expression. Transcripts encoding two zinc finger proteins, ZFP36 and ZNF161, and the tumour necrosis factor α-induced protein TNFAIP3, were also overexpressed after wounding. The role of the p38 mitogen-activated protein kinase (p38MAPK in wound healing was shown after the inhibition of p38 by SB203580, but our results also suggest the existence of surrogate activating pathways.

  10. Mitochondrial DNA copy number variation across human cancers.

    Science.gov (United States)

    Reznik, Ed; Miller, Martin L; Şenbabaoğlu, Yasin; Riaz, Nadeem; Sarungbam, Judy; Tickoo, Satish K; Al-Ahmadie, Hikmat A; Lee, William; Seshan, Venkatraman E; Hakimi, A Ari; Sander, Chris

    2016-02-22

    Mutations, deletions, and changes in copy number of mitochondrial DNA (mtDNA), are observed throughout cancers. Here, we survey mtDNA copy number variation across 22 tumor types profiled by The Cancer Genome Atlas project. We observe a tendency for some cancers, especially of the bladder, breast, and kidney, to be depleted of mtDNA, relative to matched normal tissue. Analysis of genetic context reveals an association between incidence of several somatic alterations, including IDH1 mutations in gliomas, and mtDNA content. In some but not all cancer types, mtDNA content is correlated with the expression of respiratory genes, and anti-correlated to the expression of immune response and cell-cycle genes. In tandem with immunohistochemical evidence, we find that some tumors may compensate for mtDNA depletion to sustain levels of respiratory proteins. Our results highlight the extent of mtDNA copy number variation in tumors and point to related therapeutic opportunities.

  11. Polymorphisms in human DNA repair genes and head and neck ...

    Indian Academy of Sciences (India)

    Genetic polymorphisms in some DNA repair proteins are associated with a number of malignant transformations like head and neck squamous cell carcinoma (HNSCC). Xeroderma pigmentosum group D (XPD) and X-ray repair cross-complementing proteins 1 (XRCC1) and 3 (XRCC3) genes are involved in DNA repair ...

  12. Quantification and presence of human ancient DNA in burial place ...

    African Journals Online (AJOL)

    ... was shown to consists of intact DNA that is virtually free of RNA, resulting in a more accurate representation of gene expression using RTPCR and PCR amplification methods. In this study, the results demonstrate that RT-PCR method can be useful for the improved ancient DNA extraction in anthropology and archeology.

  13. DNA molecules and human therapeutics | Danquah | African Journal ...

    African Journals Online (AJOL)

    Nucleic acid molecules are championing a new generation of reverse engineered biopharmaceuticals. In terms of potential application in gene medicine, plasmid DNA (pDNA) vectors have exceptional therapeutic and immunological profiles as they are free from safety concerns associated with viral vectors, display ...

  14. Acute hypoxia and hypoxic exercise induce DNA strand breaks and oxidative DNA damage in humans

    DEFF Research Database (Denmark)

    Møller, P; Loft, S; Lundby, C

    2001-01-01

    The present study investigated the effect of a single bout of exhaustive exercise on the generation of DNA strand breaks and oxidative DNA damage under normal conditions and at high-altitude hypoxia (4559 meters for 3 days). Twelve healthy subjects performed a maximal bicycle exercise test; lymph...

  15. Reducing microbial and human contamination in DNA extractions from ancient bones and teeth.

    Science.gov (United States)

    Korlević, Petra; Gerber, Tobias; Gansauge, Marie-Theres; Hajdinjak, Mateja; Nagel, Sarah; Aximu-Petri, Ayinuer; Meyer, Matthias

    2015-08-01

    Although great progress has been made in improving methods for generating DNA sequences from ancient biological samples, many, if not most, samples are still not amenable for analyses due to overwhelming contamination with microbial or modern human DNA. Here we explore different DNA decontamination procedures for ancient bones and teeth for use prior to DNA library preparation and high-throughput sequencing. Two procedures showed promising results: (i) the release of surface-bound DNA by phosphate buffer and (ii) the removal of DNA contamination by sodium hypochlorite treatment. Exposure to phosphate removes on average 64% of the microbial DNA from bone powder but only 37% of the endogenous DNA (from the organism under study), increasing the percentage of informative sequences by a factor of two on average. An average 4.6-fold increase, in one case reaching 24-fold, is achieved by sodium hypochlorite treatment, albeit at the expense of destroying 63% of the endogenous DNA preserved in the bone. While both pretreatment methods described here greatly reduce the cost of genome sequencing from ancient material due to efficient depletion of microbial DNA, we find that the removal of human DNA contamination remains a challenging problem.

  16. Quantitative methods of analysis of footprinting diagrams for the complexes formed by a ligand with a DNA fragment of known sequence.

    Science.gov (United States)

    Nechipurenko, Yurii D; Jovanovic, Bosko; Riabokon, Vadim F; Gursky, Georgii V

    2005-06-01

    The regulation of gene expression is based on the interaction of DNA with different ligands. A model of adsorption was considered that can be applied to the quantitative analysis of footprinting diagrams for the complexes formed by a ligand with a DNA fragment of known structure. This model allows the probabilities of ligand binding to DNA sites with a known sequence to be calculated and the variance of probabilities of ligand binding with a specified binding site to be estimated. The model was used for quantitative analysis of diagrams of DNAse footprinting for the complexes of the dimeric analogue of the antitumor antibiotic netropsin. Experimental and theoretically calculated profiles of distribution of netropsin bound on DNA are in good agreement with one another.

  17. Sunlight-induced DNA damage in human mononuclear cells

    DEFF Research Database (Denmark)

    Møller, Peter; Wallin, Hakan; Holst, Erik

    2002-01-01

    In this study of 301 blood samples from 21 subjects, we found markedly higher levels of DNA damage (nonpyrimidine dimer types) in the summer than in the winter detected by single-cell gel electrophoresis. The level of DNA damage was influenced by the average daily influx of sunlight ... to blood sampling. The 3 and 6 day periods before sampling influenced DNA damage the most. The importance of sunlight was further emphasized by a positive association of the DNA damage level to the amount of time the subjects had spent in the sun over a 3 day period prior to the sampling. The effect...... of sunlight was comparable to the interindividual variation, indicating that sunlight exposure and the individual's background were the two most important determinants for the basal level of DNA damage. Influence of other lifestyle factors such as exercise, intake of foods, infections, and age could...

  18. Rethinking research in the medical humanities: a scoping review and narrative synthesis of quantitative outcome studies.

    Science.gov (United States)

    Dennhardt, Silke; Apramian, Tavis; Lingard, Lorelei; Torabi, Nazi; Arntfield, Shannon

    2016-03-01

    The rise of medical humanities teaching in medical education has introduced pressure to prove efficacy and utility. Review articles on the available evidence have been criticised for poor methodology and unwarranted conclusions. To support a more nuanced discussion of how the medical humanities work, we conducted a scoping review of quantitative studies of medical humanities teaching. Using a search strategy involving MEDLINE, EMBASE and ERIC, and hand searching, our scoping review located 11 045 articles that referred to the use of medical humanities teaching in medical education. Of these, 62 studies using quantitative evaluation methods were selected for review. Three iterations of analysis were performed: descriptive, conceptual, and discursive. Descriptive analysis revealed that the medical humanities as a whole cannot be easily systematised based on simple descriptive categories. Conceptual analysis supported the development of a conceptual framework in which the foci of the arts and humanities in medical education can be mapped alongside their related epistemic functions for teaching and learning. Within the framework, art functioned as expertise, as dialogue or as a means of expression and transformation. In the discursive analysis, we found three main ways in which the relationship between the arts and humanities and medicine was constructed as, respectively, intrinsic, additive and curative. This review offers a nuanced framework of how different types of medical humanities work. The epistemological assumptions and discursive positioning of medical humanities teaching frame the forms of outcomes research that are considered relevant to curriculum decision making, and shed light on why dominant review methodologies make some functions of medical humanities teaching visible and render others invisible. We recommend the use of this framework to improve the rigor and relevance of future explorations of the efficacy and utility of medical humanities teaching

  19. DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease

    Energy Technology Data Exchange (ETDEWEB)

    Dupuy, Aurélie [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Sarasin, Alain, E-mail: alain.sarasin@gustaveroussy.fr [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Service de Génétique, Institut Gustave Roussy (France)

    2015-06-15

    Graphical abstract: - Highlights: • Full correction of mutation in the XPC gene by engineered nucleases. • Meganucleases and TALENs are inhibited by 5-MeC for inducing double strand breaks. • Gene therapy of XP cells is possible using homologous recombination for DSB repair. - Abstract: Xeroderma pigmentosum (XP) is a genetic disease characterized by hypersensitivity to ultra-violet and a very high risk of skin cancer induction on exposed body sites. This syndrome is caused by germinal mutations on nucleotide excision repair genes. No cure is available for these patients except a complete protection from all types of UV radiations. We reviewed the various techniques to complement or to correct the genetic defect in XP cells. We, particularly, developed the correction of XP-C skin cells using the fidelity of the homologous recombination pathway during repair of double-strand break (DSB) in the presence of XPC wild type sequences. We used engineered nucleases (meganuclease or TALE nuclease) to induce a DSB located at 90 bp of the mutation to be corrected. Expression of specific TALE nuclease in the presence of a repair matrix containing a long stretch of homologous wild type XPC sequences allowed us a successful gene correction of the original TG deletion found in numerous North African XP patients. Some engineered nucleases are sensitive to epigenetic modifications, such as cytosine methylation. In case of methylated sequences to be corrected, modified nucleases or demethylation of the whole genome should be envisaged. Overall, we showed that specifically-designed TALE-nuclease allowed us to correct a 2 bp deletion in the XPC gene leading to patient's cells proficient for DNA repair and showing normal UV-sensitivity. The corrected gene is still in the same position in the human genome and under the regulation of its physiological promoter. This result is a first step toward gene therapy in XP patients.

  20. Universal and blocking primer mismatches limit the use of high-throughput DNA sequencing for the quantitative metabarcoding of arthropods.

    Science.gov (United States)

    Piñol, J; Mir, G; Gomez-Polo, P; Agustí, N

    2015-07-01

    The quantification of the biological diversity in environmental samples using high-throughput DNA sequencing is hindered by the PCR bias caused by variable primer-template mismatches of the individual species. In some dietary studies, there is the added problem that samples are enriched with predator DNA, so often a predator-specific blocking oligonucleotide is used to alleviate the problem. However, specific blocking oligonucleotides could coblock nontarget species to some degree. Here, we accurately estimate the extent of the PCR biases induced by universal and blocking primers on a mock community prepared with DNA of twelve species of terrestrial arthropods. We also compare universal and blocking primer biases with those induced by variable annealing temperature and number of PCR cycles. The results show that reads of all species were recovered after PCR enrichment at our control conditions (no blocking oligonucleotide, 45 °C annealing temperature and 40 cycles) and high-throughput sequencing. They also show that the four factors considered biased the final proportions of the species to some degree. Among these factors, the number of primer-template mismatches of each species had a disproportionate effect (up to five orders of magnitude) on the amplification efficiency. In particular, the number of primer-template mismatches explained most of the variation (~3/4) in the amplification efficiency of the species. The effect of blocking oligonucleotide concentration on nontarget species relative abundance was also significant, but less important (below one order of magnitude). Considering the results reported here, the quantitative potential of the technique is limited, and only qualitative results (the species list) are reliable, at least when targeting the barcoding COI region. © 2014 John Wiley & Sons Ltd.

  1. RNA2DNAlign: nucleotide resolution allele asymmetries through quantitative assessment of RNA and DNA paired sequencing data.

    Science.gov (United States)

    Movassagh, Mercedeh; Alomran, Nawaf; Mudvari, Prakriti; Dede, Merve; Dede, Cem; Kowsari, Kamran; Restrepo, Paula; Cauley, Edmund; Bahl, Sonali; Li, Muzi; Waterhouse, Wesley; Tsaneva-Atanasova, Krasimira; Edwards, Nathan; Horvath, Anelia

    2016-12-15

    We introduce RNA2DNAlign, a computational framework for quantitative assessment of allele counts across paired RNA and DNA sequencing datasets. RNA2DNAlign is based on quantitation of the relative abundance of variant and reference read counts, followed by binomial tests for genotype and allelic status at SNV positions between compatible sequences. RNA2DNAlign detects positions with differential allele distribution, suggesting asymmetries due to regulatory/structural events. Based on the type of asymmetry, RNA2DNAlign outlines positions likely to be implicated in RNA editing, allele-specific expression or loss, somatic mutagenesis or loss-of-heterozygosity (the first three also in a tumor-specific setting). We applied RNA2DNAlign on 360 matching normal and tumor exomes and transcriptomes from 90 breast cancer patients from TCGA. Under high-confidence settings, RNA2DNAlign identified 2038 distinct SNV sites associated with one of the aforementioned asymetries, the majority of which have not been linked to functionality before. The performance assessment shows very high specificity and sensitivity, due to the corroboration of signals across multiple matching datasets. RNA2DNAlign is freely available from http://github.com/HorvathLab/NGS as a self-contained binary package for 64-bit Linux systems. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Human gamma-satellite DNA maintains open chromatin structure and protects a transgene from epigenetic silencing.

    Science.gov (United States)

    Kim, Jung-Hyun; Ebersole, Thomas; Kouprina, Natalay; Noskov, Vladimir N; Ohzeki, Jun-Ichirou; Masumoto, Hiroshi; Mravinac, Brankica; Sullivan, Beth A; Pavlicek, Adam; Dovat, Sinisa; Pack, Svetlana D; Kwon, Yoo-Wook; Flanagan, Patrick T; Loukinov, Dmitri; Lobanenkov, Victor; Larionov, Vladimir

    2009-04-01

    The role of repetitive DNA sequences in pericentromeric regions with respect to kinetochore/heterochromatin structure and function is poorly understood. Here, we use a mouse erythroleukemia cell (MEL) system for studying how repetitive DNA assumes or is assembled into different chromatin structures. We show that human gamma-satellite DNA arrays allow a transcriptionally permissive chromatin conformation in an adjacent transgene and efficiently protect it from epigenetic silencing. These arrays contain CTCF and Ikaros binding sites. In MEL cells, this gamma-satellite DNA activity depends on binding of Ikaros proteins involved in differentiation along the hematopoietic pathway. Given our discovery of gamma-satellite DNA in pericentromeric regions of most human chromosomes and a dynamic chromatin state of gamma-satellite arrays in their natural location, we suggest that gamma-satellite DNA represents a unique region of the functional centromere with a possible role in preventing heterochromatin spreading beyond the pericentromeric region.

  3. Quantitative analysis of the expression of ACAT genes in human tissues by real-time PCR.

    Science.gov (United States)

    Smith, Jeffery L; Rangaraj, Kavitha; Simpson, Robert; Maclean, Donald J; Nathanson, Les K; Stuart, Katherine A; Scott, Shaun P; Ramm, Grant A; de Jersey, John

    2004-04-01

    ACAT (also called sterol o-acyltransferase) catalyzes the esterification of cholesterol by reaction with long-chain acyl-CoA derivatives and plays a pivotal role in the regulation of cholesterol homeostasis. Although two human ACAT genes termed ACAT-1 and ACAT-2 have been reported, prior research on differential tissue expression is qualitative and incomplete. We have developed a quantitative multiplex assay for each ACAT isoform after RT treatment of total RNA using TaqMan real-time quantitative PCR normalized to beta-actin in the same reaction tube. This enabled us to calculate the relative abundance of transcripts in several human tissues as an ACAT-2/ACAT-1 ratio. In liver (n = 17), ACAT-1 transcripts were on average 9-fold (range, 1.7- to 167-fold) more abundant than ACAT-2, whereas in duodenal samples (n = 10), ACAT-2 transcripts were on average 3-fold (range, 0.39- to 12.2-fold) more abundant than ACAT-1. ACAT-2 was detected for the first time in peripheral blood mononuclear cells. Interesting differences in ACAT-2 mRNA expression were evident in subgroup analysis of samples from different sources. These results demonstrate quantitatively that ACAT-1 transcripts predominate in human liver and ACAT-2 transcripts predominate in human duodenum and support the notion that ACAT-2 has an important regulatory role in liver and intestine.

  4. Identification of novel tumor-associated cell surface sialoglycoproteins in human glioblastoma tumors using quantitative proteomics.

    Directory of Open Access Journals (Sweden)

    François Autelitano

    Full Text Available Glioblastoma multiform (GBM remains clinical indication with significant "unmet medical need". Innovative new therapy to eliminate residual tumor cells and prevent tumor recurrences is critically needed for this deadly disease. A major challenge of GBM research has been the identification of novel molecular therapeutic targets and accurate diagnostic/prognostic biomarkers. Many of the current clinical therapeutic targets of immunotoxins and ligand-directed toxins for high-grade glioma (HGG cells are surface sialylated glycoproteins. Therefore, methods that systematically and quantitatively analyze cell surface sialoglycoproteins in human clinical tumor samples would be useful for the identification of potential diagnostic markers and therapeutic targets for malignant gliomas. In this study, we used the bioorthogonal chemical reporter strategy (BOCR in combination with label-free quantitative mass spectrometry (LFQ-MS to characterize and accurately quantify the individual cell surface sialoproteome in human GBM tissues, in fetal, adult human astrocytes, and in human neural progenitor cells (NPCs. We identified and quantified a total of 843 proteins, including 801 glycoproteins. Among the 843 proteins, 606 (72% are known cell surface or secreted glycoproteins, including 156 CD-antigens, all major classes of cell surface receptor proteins, transporters, and adhesion proteins. Our findings identified several known as well as new cell surface antigens whose expression is predominantly restricted to human GBM tumors as confirmed by microarray transcription profiling, quantitative RT-PCR and immunohistochemical staining. This report presents the comprehensive identification of new biomarkers and therapeutic targets for the treatment of malignant gliomas using quantitative sialoglycoproteomics with clinically relevant, patient derived primary glioma cells.

  5. DNA Catenation Maintains Structure of Human Metaphase Chromosomes

    DEFF Research Database (Denmark)

    L. V. Bauer, David; Marie, Rodolphe; Rasmussen, Kristian Hagsted

    2012-01-01

    Mitotic chromosome structure is pivotal to cell division but difficult to observe in fine detail using conventional methods. DNA catenation has been implicated in both sister chromatid cohesion and chromosome condensation, but has never been observed directly. We have used a lab-on-a-chip microfl......Mitotic chromosome structure is pivotal to cell division but difficult to observe in fine detail using conventional methods. DNA catenation has been implicated in both sister chromatid cohesion and chromosome condensation, but has never been observed directly. We have used a lab......-on-a-chip microfluidic device and fluorescence microscopy, coupled with a simple image analysis pipeline, to digest chromosomal proteins and examine the structure of the remaining DNA, which maintains the canonical ‘X’ shape. By directly staining DNA, we observe that DNA catenation between sister chromatids (separated...... by fluid flow) is composed of distinct fibres of DNA concentrated at the centromeres. Disrupting the catenation of the chromosomes with Topoisomerase IIa significantly alters overall chromosome shape, suggesting that DNA catenation must be simultaneously maintained for correct chromosome condensation...

  6. Forensic DNA Phenotyping: Predicting human appearance from crime scene material for investigative purposes.

    Science.gov (United States)

    Kayser, Manfred

    2015-09-01

    Forensic DNA Phenotyping refers to the prediction of appearance traits of unknown sample donors, or unknown deceased (missing) persons, directly from biological materials found at the scene. "Biological witness" outcomes of Forensic DNA Phenotyping can provide investigative leads to trace unknown persons, who are unidentifiable with current comparative DNA profiling. This intelligence application of DNA marks a substantially different forensic use of genetic material rather than that of current DNA profiling presented in the courtroom. Currently, group-specific pigmentation traits are already predictable from DNA with reasonably high accuracies, while several other externally visible characteristics are under genetic investigation. Until individual-specific appearance becomes accurately predictable from DNA, conventional DNA profiling needs to be performed subsequent to appearance DNA prediction. Notably, and where Forensic DNA Phenotyping shows great promise, this is on a (much) smaller group of potential suspects, who match the appearance characteristics DNA-predicted from the crime scene stain or from the deceased person's remains. Provided sufficient funding being made available, future research to better understand the genetic basis of human appearance will expectedly lead to a substantially more detailed description of an unknown person's appearance from DNA, delivering increased value for police investigations in criminal and missing person cases involving unknowns. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Molecular cloning and mammalian expression of human beta 2-glycoprotein I cDNA

    DEFF Research Database (Denmark)

    Kristensen, Torsten; Schousboe, Inger; Boel, Espen

    1991-01-01

    Human β2-glycoprotein (β2gpI) cDNA was isolated from a liver cDNA library and sequenced. The cDNA encoded a 19-residue hydrophobic signal peptide followed by the mature β2gpI of 326 amino acid residues. In liver and in the hepatoma cell line HepG2 there are two mRNA species of about 1.4 and 4.3 kb...

  8. Human circulating plasma DNA significantly decreases while lymphocyte DNA damage increases under chronic occupational exposure to low-dose gamma-neutron and tritium β-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Korzeneva, Inna B., E-mail: inna.korzeneva@molgen.vniief.ru [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Kostuyk, Svetlana V.; Ershova, Liza S. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation); Osipov, Andrian N. [Federal Medial and Biological Center named after Burnazyan of the Federal Medical and Biological Agency (FMBTz named after Burnazyan of FMBA), Moscow (Russian Federation); State Research Center - Burnasyan Federal Medical Biophysical Center of Federal Medical Biological Agency, Zhivopisnaya, 46, Moscow, 123098 (Russian Federation); Zhuravleva, Veronika F.; Pankratova, Galina V. [Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics (RFNC-VNIIEF) 607190, Sarov, 37 Mira ave., Nizhniy Novgorod Region (Russian Federation); Porokhovnik, Lev N.; Veiko, Natalia N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, 115478 Moscow, 1 Moskvorechye str. (Russian Federation)

    2015-09-15

    Highlights: • The chronic exposure to low-dose IR induces DSBs in human lymphocytes (TM index). • Exposure to IR decreases the level of human circulating DNA (cfDNA index). • IR induces an increase of DNase1 activity (DNase1 index) in plasma. • IR induces an increase of the level of antibodies to DNA (Ab DNA index) in plasma. • The ratio cfDNA/(DNase 1 × Ab DNA × TM) is a potential marker of human exposure to IR. - Abstract: The blood plasma of healthy people contains cell-fee (circulating) DNA (cfDNA). Apoptotic cells are the main source of the cfDNA. The cfDNA concentration increases in case of the organism’s cell death rate increase, for example in case of exposure to high-dose ionizing radiation (IR). The objects of the present research are the blood plasma and blood lymphocytes of people, who contacted occupationally with the sources of external gamma/neutron radiation or internal β-radiation of tritium N = 176). As the controls (references), blood samples of people, who had never been occupationally subjected to the IR sources, were used (N = 109). With respect to the plasma samples of each donor there were defined: the cfDNA concentration (the cfDNA index), DNase1 activity (the DNase1 index) and titre of antibodies to DNA (the Ab DNA index). The general DNA damage in the cells was defined (using the Comet assay, the tail moment (TM) index). A chronic effect of the low-dose ionizing radiation on a human being is accompanied by the enhancement of the DNA damage in lymphocytes along with a considerable cfDNA content reduction, while the DNase1 content and concentration of antibodies to DNA (Ab DNA) increase. All the aforementioned changes were also observed in people, who had not worked with the IR sources for more than a year. The ratio cfDNA/(DNase1 × Ab DNA × TM) is proposed to be used as a marker of the chronic exposure of a person to the external low-dose IR. It was formulated the assumption that the joint analysis of the cfDNA, DNase1, Ab

  9. Nuclear DNA Content Varies with Cell Size across Human Cell Types

    Science.gov (United States)

    Gillooly, James F.; Hein, Andrew; Damiani, Rachel

    2015-01-01

    Variation in the size of cells, and the DNA they contain, is a basic feature of multicellular organisms that affects countless aspects of their structure and function. Within humans, cell size is known to vary by several orders of magnitude, and differences in nuclear DNA content among cells have been frequently observed. Using published data, here we describe how the quantity of nuclear DNA across 19 different human cell types increases with cell volume. This observed increase is similar to intraspecific relationships between DNA content and cell volume in other species, and interspecific relationships between diploid genome size and cell volume. Thus, we speculate that the quantity of nuclear DNA content in somatic cells of humans is perhaps best viewed as a distribution of values that reflects cell size distributions, rather than as a single, immutable quantity. PMID:26134319

  10. Nuclear DNA Content Varies with Cell Size across Human Cell Types.

    Science.gov (United States)

    Gillooly, James F; Hein, Andrew; Damiani, Rachel

    2015-07-01

    Variation in the size of cells, and the DNA they contain, is a basic feature of multicellular organisms that affects countless aspects of their structure and function. Within humans, cell size is known to vary by several orders of magnitude, and differences in nuclear DNA content among cells have been frequently observed. Using published data, here we describe how the quantity of nuclear DNA across 19 different human cell types increases with cell volume. This observed increase is similar to intraspecific relationships between DNA content and cell volume in other species, and interspecific relationships between diploid genome size and cell volume. Thus, we speculate that the quantity of nuclear DNA content in somatic cells of humans is perhaps best viewed as a distribution of values that reflects cell size distributions, rather than as a single, immutable quantity. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  11. Repair of DNA damage in light sensitive human skin diseases

    Energy Technology Data Exchange (ETDEWEB)

    Horkay, I.; Varga, L.; Tam' asi P., Gundy, S.

    1978-12-01

    Repair of uv-light induced DNA damage and changes in the semiconservative DNA synthesis were studied by in vitro autoradiography in the skin of patients with lightdermatoses (polymorphous light eruption, porphyria cutanea tarda, erythropoietic protoporphyria) and xeroderma pigmentosum as well as in that of healthy controls. In polymorphous light eruption the semiconservative DNA replication rate was more intensive in the area of the skin lesions and in the repeated phototest site, the excision repair synthesis appeared to be unaltered. In cutaneous prophyrias a decreased rate of the repair incorporation could be detected. Xeroderma pigmentosum was characterized by a strongly reduced repair synthesis.

  12. Assessing DNA methylation in the developing human intestinal epithelium: potential link to inflammatory bowel disease.

    Science.gov (United States)

    Kraiczy, J; Nayak, K; Ross, A; Raine, T; Mak, T N; Gasparetto, M; Cario, E; Rakyan, V; Heuschkel, R; Zilbauer, M

    2016-05-01

    DNA methylation is one of the major epigenetic mechanisms implicated in regulating cellular development and cell-type-specific gene expression. Here we performed simultaneous genome-wide DNA methylation and gene expression analysis on purified intestinal epithelial cells derived from human fetal gut, healthy pediatric biopsies, and children newly diagnosed with inflammatory bowel disease (IBD). Results were validated using pyrosequencing, real-time PCR, and immunostaining. The functional impact of DNA methylation changes on gene expression was assessed by employing in-vitro assays in intestinal cell lines. DNA methylation analyses allowed identification of 214 genes for which expression is regulated via DNA methylation, i.e. regulatory differentially methylated regions (rDMRs). Pathway and functional analysis of rDMRs suggested a critical role for DNA methylation in regulating gene expression and functional development of the human intestinal epithelium. Moreover, analysis performed on intestinal epithelium of children newly diagnosed with IBD revealed alterations in DNA methylation within genomic loci, which were found to overlap significantly with those undergoing methylation changes during intestinal development. Our study provides novel insights into the physiological role of DNA methylation in regulating functional maturation of the human intestinal epithelium. Moreover, we provide data linking developmentally acquired alterations in the DNA methylation profile to changes seen in pediatric IBD.

  13. Quantitative DNA methylation analysis improves epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome.

    Science.gov (United States)

    Calvello, Mariarosaria; Tabano, Silvia; Colapietro, Patrizia; Maitz, Silvia; Pansa, Alessandra; Augello, Claudia; Lalatta, Faustina; Gentilin, Barbara; Spreafico, Filippo; Calzari, Luciano; Perotti, Daniela; Larizza, Lidia; Russo, Silvia; Selicorni, Angelo; Sirchia, Silvia M; Miozzo, Monica

    2013-10-01

    Beckwith-Wiedemann syndrome (BWS) is a rare disorder characterized by overgrowth and predisposition to embryonal tumors. BWS is caused by various epigenetic and/or genetic alterations that dysregulate the imprinted genes on chromosome region 11p15.5. Molecular analysis is required to reinforce the clinical diagnosis of BWS and to identify BWS patients with cancer susceptibility. This is particularly crucial prenatally because most signs of BWS cannot be recognized in utero. We established a reliable molecular assay by pyrosequencing to quantitatively evaluate the methylation profiles of ICR1 and ICR2. We explored epigenotype-phenotype correlations in 19 patients that fulfilled the clinical diagnostic criteria for BWS, 22 patients with suspected BWS, and three fetuses with omphalocele. Abnormal methylation was observed in one prenatal case and 19 postnatal cases, including seven suspected BWS. Seven cases showed ICR1 hypermethylation, five cases showed ICR2 hypomethylation, and eight cases showed abnormal methylation of ICR1 and ICR2 indicating paternal uniparental disomy (UPD). More cases of ICR1 alterations and UPD were found than expected. This is likely due to the sensitivity of this approach, which can detect slight deviations in methylation from normal levels. There was a significant correlation (pdiastasis recti. Evaluation of ICR1 and ICR2 methylation by pyrosequencing in BWS can improve epigenotype-phenotype correlations, detection of methylation alterations in suspected cases, and identification of UPD.

  14. Phosphorylation of human INO80 is involved in DNA damage tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Dai; Waki, Mayumi; Umezawa, Masaki; Aoki, Yuka [Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Utsugi, Takahiko [Bio Matrix Research Inc., 105 Higashifukai, Nagareyama, Chiba 275-0101 (Japan); Ohtsu, Masaya [Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Murakami, Yasufumi, E-mail: yasufumi@rs.noda.tus.ac.jp [Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510 (Japan); Bio Matrix Research Inc., 105 Higashifukai, Nagareyama, Chiba 275-0101 (Japan)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Depletion of hINO80 significantly reduced PCNA ubiquitination. Black-Right-Pointing-Pointer Depletion of hINO80 significantly reduced nuclear dots intensity of RAD18 after UV irradiation. Black-Right-Pointing-Pointer Western blot analyses showed phosphorylated hINO80 C-terminus. Black-Right-Pointing-Pointer Overexpression of phosphorylation mutant hINO80 reduced PCNA ubiquitination. -- Abstract: Double strand breaks (DSBs) are the most serious type of DNA damage. DSBs can be generated directly by exposure to ionizing radiation or indirectly by replication fork collapse. The DNA damage tolerance pathway, which is conserved from bacteria to humans, prevents this collapse by overcoming replication blockages. The INO80 chromatin remodeling complex plays an important role in the DNA damage response. The yeast INO80 complex participates in the DNA damage tolerance pathway. The mechanisms regulating yINO80 complex are not fully understood, but yeast INO80 complex are necessary for efficient proliferating cell nuclear antigen (PCNA) ubiquitination and for recruitment of Rad18 to replication forks. In contrast, the function of the mammalian INO80 complex in DNA damage tolerance is less clear. Here, we show that human INO80 was necessary for PCNA ubiquitination and recruitment of Rad18 to DNA damage sites. Moreover, the C-terminal region of human INO80 was phosphorylated, and overexpression of a phosphorylation-deficient mutant of human INO80 resulted in decreased ubiquitination of PCNA during DNA replication. These results suggest that the human INO80 complex, like the yeast complex, was involved in the DNA damage tolerance pathway and that phosphorylation of human INO80 was involved in the DNA damage tolerance pathway. These findings provide new insights into the DNA damage tolerance pathway in mammalian cells.

  15. Specific melanin content in human hairs and mitochondrial DNA typing success.

    Science.gov (United States)

    Linch, Charles A; Champagne, Jarrod R; Bonnette, Michelle D; Dawson Cruz, Tracey

    2009-06-01

    This study investigated whether a difference exists in the ability to obtain quality mitochondrial DNA (mtDNA) sequence data from hair shafts due to specific melanin content differences. Eumelanin, the pigment in darker hairs, protects nuclear DNA in the skin by absorbing and scattering UV radiation. In contrast, sensitized pheomelanin, the predominate melanin in red hairs and some blond hairs, is unable to prevent DNA damage in skin upon exposure to UV radiation. It has been reported in the literature that darker hairs (predominate eumelanin content) have a higher mtDNA sequencing success rate than lighter colored hairs. However, others have reported to the contrary when different methodologies are used. In this study, 2-cm hair fragments were cut from dark brown, red, and gray white hairs and typed using standard casework mtDNA sequence analysis methods. All 30 hair fragments produced quality mtDNA sequence data on first attempt from the second half of hypervariable region 1. These results are likely due to the apparent shielding of mtDNA by the hard protein of the hair shaft fiber from radiation-induced damage, regardless of melanin type, after 10-months minimal solar exposure. Nonetheless, this study may serve as a guide for future quantitative studies that investigate hair mtDNA photodamage in circumstances of increased solar, chemical, environmental, or mechanical damage.

  16. Detection and quantitation of benzo(a)pyrene-DNA adducts in brain and liver tissues of Beluga whales (Delphinapterus leucas) from the St. Lawrence and Mackenzie Estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Shugart, L.R.

    1988-01-01

    It should be noted that there are few analytical techniques available for the detection and quantitation of chemical adducts in the DNA of living organisms. The reasons for this are: the analytical technique often has to accommodate the unique chemical and/or physical properties of the individual chemical or its metabolite; the percentage of total chemical that becomes most of the parent compound is usually detoxified and excreted; not all adducts that form between the genotoxic agent and DNA are stable or are involved in the development of subsequent deleterious events in the organism; and the amount of DNA available for analysis is often quite limited. 16 refs., 1 tab.

  17. 3D quantitative analysis of early decomposition changes of the human face.

    Science.gov (United States)

    Caplova, Zuzana; Gibelli, Daniele Maria; Poppa, Pasquale; Cummaudo, Marco; Obertova, Zuzana; Sforza, Chiarella; Cattaneo, Cristina

    2017-07-13

    Decomposition of the human body and human face is influenced, among other things, by environmental conditions. The early decomposition changes that modify the appearance of the face may hamper the recognition and identification of the deceased. Quantitative assessment of those changes may provide important information for forensic identification. This report presents a pilot 3D quantitative approach of tracking early decomposition changes of a single cadaver in controlled environmental conditions by summarizing the change with weekly morphological descriptions. The root mean square (RMS) value was used to evaluate the changes of the face after death. The results showed a high correlation (r = 0.863) between the measured RMS and the time since death. RMS values of each scan are presented, as well as the average weekly RMS values. The quantification of decomposition changes could improve the accuracy of antemortem facial approximation and potentially could allow the direct comparisons of antemortem and postmortem 3D scans.

  18. A Network Neuroscience of Human Learning: Potential to Inform Quantitative Theories of Brain and Behavior.

    Science.gov (United States)

    Bassett, Danielle S; Mattar, Marcelo G

    2017-04-01

    Humans adapt their behavior to their external environment in a process often facilitated by learning. Efforts to describe learning empirically can be complemented by quantitative theories that map changes in neurophysiology to changes in behavior. In this review we highlight recent advances in network science that offer a sets of tools and a general perspective that may be particularly useful in understanding types of learning that are supported by distributed neural circuits. We describe recent applications of these tools to neuroimaging data that provide unique insights into adaptive neural processes, the attainment of knowledge, and the acquisition of new skills, forming a network neuroscience of human learning. While promising, the tools have yet to be linked to the well-formulated models of behavior that are commonly utilized in cognitive psychology. We argue that continued progress will require the explicit marriage of network approaches to neuroimaging data and quantitative models of behavior. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. QUANTITATIVE VS. CONVENTIONAL PCR FOR DETECTION OF HUMAN ADENOVIRUSES IN WATER AND SEDIMENT SAMPLES

    Directory of Open Access Journals (Sweden)

    Rodrigo STAGGEMEIER

    2015-08-01

    Full Text Available SUMMARY Human Adenoviruses (HAdV are notably resistant in the environment. These agents may serve as effective indicators of fecal contamination, and may act as causative agents of a number of different diseases in human beings. Conventional polymerase chain reaction (PCR and, more recently, quantitative PCR (qPCR are widely used for detection of viral agents in environmental matrices. In the present study PCR and SYBR(rGreen qPCR assays were compared for detection of HAdV in water (55 and sediments (20 samples of spring and artesian wells, ponds and streams, collected from dairy farms. By the quantitative methodology HAdV were detected in 87.3% of the water samples and 80% of the sediments, while by the conventional PCR 47.3% and 35% were detected in water samples and sediments, respectively.

  20. A Mini-Library of Sequenced Human DNA Fragments: Linking Bench Experiments with Informatics

    Science.gov (United States)

    Dalgleish, Raymond; Shanks, Morag E.; Monger, Karen; Butler, Nicola J.

    2012-01-01

    We describe the development of a mini-library of human DNA fragments for use in an enquiry-based learning (EBL) undergraduate practical incorporating "wet-lab" and bioinformatics tasks. In spite of the widespread emergence of the polymerase chain reaction (PCR), the cloning and analysis of DNA fragments in "Escherichia coli"…

  1. More on contamination: the use of asymmetric molecular behavior to identify authentic ancient human DNA

    DEFF Research Database (Denmark)

    Malmström, Helena; Svensson, Emma M; Gilbert, M Thomas P

    2007-01-01

    the reliability of one of the proposed criteria, that of appropriate molecular behavior. Using real-time polymerase chain reaction (PCR) and pyrosequencing, we have quantified the relative levels of authentic aDNA and contaminant human DNA sequences recovered from archaeological dog and cattle remains. In doing...

  2. DNA from Pre-Clovis Human Coprolites in Oregon, North America

    DEFF Research Database (Denmark)

    Gilbert, M Thomas P; Jenkins, Dennis L; Götherstrom, Anders

    2008-01-01

    Caves, south-central Oregon, by 12,300 (14)C yr. B.P., through recovery of human mtDNA from coprolites, directly dated by accelerator mass spectrometry. The mtDNA corresponds to Native American founding haplogroups A2 and B2. The dates of the coprolites are >1000 (14)C years earlier than currently...

  3. Role of extracellular DNA oxidative modification in radiation induced bystander effects in human endotheliocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kostyuk, Svetlana V. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Alekseeva, Anna Yu.; Smirnova, Tatiana D.; Glebova, Kristina V.; Efremova, Liudmila V. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Baranova, Ancha [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); School of System Biology, George Mason University, Fairfax, VA 22030 (United States); Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2012-01-03

    The development of the bystander effect induced by low doses of irradiation in human umbilical vein endothelial cells (HUVECs) depends on extracellular DNA (ecDNA) signaling pathway. We found that the changes in the levels of ROS and NO production by human endothelial cells are components of the radiation induced bystander effect that can be registered at a low dose. We exposed HUVECs to X-ray radiation and studied effects of ecDNA{sup R} isolated from the culture media conditioned by the short-term incubation of irradiated cells on intact HUVECs. Effects of ecDNA{sup R} produced by irradiated cells on ROS and NO production in non-irradiated HUVECs are similar to bystander effect. These effects at least partially depend on TLR9 signaling. We compared the production of the nitric oxide and the ROS in human endothelial cells that were (1) irradiated at a low dose; (2) exposed to the ecDNA{sup R} extracted from the media conditioned by irradiated cells; and (3) exposed to human DNA oxidized in vitro. We found that the cellular responses to all three stimuli described above are essentially similar. We conclude that irradiation-related oxidation of the ecDNA is an important component of the ecDNA-mediated bystander effect.

  4. Genome-wide DNA methylation levels and altered cortisol stress reactivity following childhood trauma in humans

    NARCIS (Netherlands)

    Houtepen, Lotte C|info:eu-repo/dai/nl/413662802; Vinkers, Christiaan H|info:eu-repo/dai/nl/304824755; Carrillo-Roa, Tania; Hiemstra, Marieke; van Lier, Pol A; Meeus, Wim; Branje, Susan; Heim, Christine M; Nemeroff, Charles B; Mill, Jonathan; Schalkwyk, Leonard C; Creyghton, Menno P|info:eu-repo/dai/nl/336269471; Kahn, René S|info:eu-repo/dai/nl/073778532; Joëls, Marian|info:eu-repo/dai/nl/070219249; Binder, Elisabeth B; Boks, Marco P M|info:eu-repo/dai/nl/286852071

    2016-01-01

    DNA methylation likely plays a role in the regulation of human stress reactivity. Here we show that in a genome-wide analysis of blood DNA methylation in 85 healthy individuals, a locus in the Kit ligand gene (KITLG; cg27512205) showed the strongest association with cortisol stress reactivity (P=5.8

  5. Human SIRT6 promotes DNA end resection through CtIP deacetylation

    DEFF Research Database (Denmark)

    Kaidi, Abderrahmane; Weinert, Brian T; Choudhary, Chunaram

    2010-01-01

    SIRT6 belongs to the sirtuin family of protein lysine deacetylases, which regulate aging and genome stability. We found that human SIRT6 has a role in promoting DNA end resection, a crucial step in DNA double-strand break (DSB) repair by homologous recombination. SIRT6 depletion impaired the accu...

  6. Problem-Solving Test: Analysis of DNA Damage Recognizing Proteins in Yeast and Human Cells

    Science.gov (United States)

    Szeberenyi, Jozsef

    2013-01-01

    The experiment described in this test was aimed at identifying DNA repair proteins in human and yeast cells. Terms to be familiar with before you start to solve the test: DNA repair, germline mutation, somatic mutation, inherited disease, cancer, restriction endonuclease, radioactive labeling, [alpha-[superscript 32]P]ATP, [gamma-[superscript…

  7. Quantum dot based DNA nanosensors for amplification-free detection of human topoisomerase I

    DEFF Research Database (Denmark)

    Jepsen, Morten Leth; Ottaviani, Alessio; Knudsen, Birgitta R.

    2014-01-01

    We develop a quantum dot based DNA nanosensor specifically targeting the cleavage–religation activity of an essential DNA-modifying enzyme, human topoisomerase I. The assay has shown great promise in biological crude samples and thus is expected to contribute to clinical diagnostics and anti...

  8. The DNA sequence, annotation and analysis of human chromosome 3

    DEFF Research Database (Denmark)

    Muzny, Donna M; Scherer, Steven E; Kaul, Rajinder

    2006-01-01

    After the completion of a draft human genome sequence, the International Human Genome Sequencing Consortium has proceeded to finish and annotate each of the 24 chromosomes comprising the human genome. Here we describe the sequencing and analysis of human chromosome 3, one of the largest human chr...

  9. Mechanisms of interstrand DNA crosslink repair and human disorders.

    Science.gov (United States)

    Hashimoto, Satoru; Anai, Hirofumi; Hanada, Katsuhiro

    2016-01-01

    Interstrand DNA crosslinks (ICLs) are the link between Watson-Crick strands of DNAs with the covalent bond and prevent separation of DNA strands. Since the ICL lesion affects both strands of the DNA, the ICL repair is not simple. So far, nucleotide excision repair (NER), structure-specific endonucleases, translesion DNA synthesis (TLS), homologous recombination (HR), and factors responsible for Fanconi anemia (FA) are identified to be involved in ICL repair. Since the presence of ICL lesions causes severe defects in transcription and DNA replication, mutations in these DNA repair pathways give rise to a various hereditary disorders. NER plays an important role for the ICL recognition and removal in quiescent cells, and defects of NER causes congential progeria syndrome, such as xeroderma pigmentosum, Cockayne syndrome, and trichothiodystrophy. On the other hand, the ICL repair in S phase requires more complicated orchestration of multiple factors, including structure-specific endonucleases, and TLS, and HR. Disturbed this ICL repair orchestration in S phase causes genome instability resulting a cancer prone disease, Fanconi anemia. So far more than 30 factors in ICL repair have already identified. Recently, a new factor, UHRF1, was discovered as a sensor of ICLs. In addition to this, numbers of nucleases that are involved in the first incision, also called unhooking, of ICL lesions have also been identified. Here we summarize the recent studies of ICL associated disorders and repair mechanism, with emphasis in the first incision of ICLs.

  10. Prolonged incubation of processed human spermatozoa will increase DNA fragmentation.

    Science.gov (United States)

    Nabi, A; Khalili, M A; Halvaei, I; Roodbari, F

    2014-05-01

    One of the causes of failure in ART is sperm DNA fragmentation which may be associated with long period of spermatozoa incubation at 37 °C. The objective was to evaluate the rate of sperm DNA fragmentation using the sperm chromatin dispersion (SCD) test after swim-up at different time intervals prior to use. In this prospective study, 21 normozoospermic specimens were analysed. The samples were incubated at 37 °C after preparation by direct swim-up. DNA fragmentation was assessed at different time intervals (0, 1, 2 and 3 h) using SCD test. Spermatozoa with no DNA fragmentation showed large- or medium-sized halos, and sperm cells with DNA fragmentation showed either a small halo or no halo. The rates of normal morphology and progressive motility after sperm processing were 72.33 ± 2.53% and 90 ± 1.02%, respectively. The rate of sperm DNA fragmentation was significantly higher after 2 h (8.81 ± 0.93%, P = 0.004) and 3 h (10.76 ± 0.89%, P fragmentation. Therefore, sperm samples intended for ART procedures should be used within 2 h of incubation at 37 °C. © 2013 Blackwell Verlag GmbH.

  11. An Improved Methodology to Overcome Key Issues in Human Fecal Metagenomic DNA Extraction

    Directory of Open Access Journals (Sweden)

    Jitendra Kumar

    2016-12-01

    Full Text Available Microbes are ubiquitously distributed in nature, and recent culture-independent studies have highlighted the significance of gut microbiota in human health and disease. Fecal DNA is the primary source for the majority of human gut microbiome studies. However, further improvement is needed to obtain fecal metagenomic DNA with sufficient amount and good quality but low host genomic DNA contamination. In the current study, we demonstrate a quick, robust, unbiased, and cost-effective method for the isolation of high molecular weight (>23 kb metagenomic DNA (260/280 ratio >1.8 with a good yield (55.8 ± 3.8 ng/mg of feces. We also confirm that there is very low human genomic DNA contamination (eubacterial: human genomic DNA marker genes = 227.9:1 in the human feces. The newly-developed method robustly performs for fresh as well as stored fecal samples as demonstrated by 16S rRNA gene sequencing using 454 FLX+. Moreover, 16S rRNA gene analysis indicated that compared to other DNA extraction methods tested, the fecal metagenomic DNA isolated with current methodology retains species richness and does not show microbial diversity biases, which is further confirmed by qPCR with a known quantity of spike-in genomes. Overall, our data highlight a protocol with a balance between quality, amount, user-friendliness, and cost effectiveness for its suitability toward usage for culture-independent analysis of the human gut microbiome, which provides a robust solution to overcome key issues associated with fecal metagenomic DNA isolation in human gut microbiome studies.

  12. An Improved Methodology to Overcome Key Issues in Human Fecal Metagenomic DNA Extraction.

    Science.gov (United States)

    Kumar, Jitendra; Kumar, Manoj; Gupta, Shashank; Ahmed, Vasim; Bhambi, Manu; Pandey, Rajesh; Chauhan, Nar Singh

    2016-12-01

    Microbes are ubiquitously distributed in nature, and recent culture-independent studies have highlighted the significance of gut microbiota in human health and disease. Fecal DNA is the primary source for the majority of human gut microbiome studies. However, further improvement is needed to obtain fecal metagenomic DNA with sufficient amount and good quality but low host genomic DNA contamination. In the current study, we demonstrate a quick, robust, unbiased, and cost-effective method for the isolation of high molecular weight (>23kb) metagenomic DNA (260/280 ratio >1.8) with a good yield (55.8±3.8ng/mg of feces). We also confirm that there is very low human genomic DNA contamination (eubacterial: human genomic DNA marker genes=227.9:1) in the human feces. The newly-developed method robustly performs for fresh as well as stored fecal samples as demonstrated by 16S rRNA gene sequencing using 454 FLX+. Moreover, 16S rRNA gene analysis indicated that compared to other DNA extraction methods tested, the fecal metagenomic DNA isolated with current methodology retains species richness and does not show microbial diversity biases, which is further confirmed by qPCR with a known quantity of spike-in genomes. Overall, our data highlight a protocol with a balance between quality, amount, user-friendliness, and cost effectiveness for its suitability toward usage for culture-independent analysis of the human gut microbiome, which provides a robust solution to overcome key issues associated with fecal metagenomic DNA isolation in human gut microbiome studies. Copyright © 2016 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

  13. Quantitative DNA methylation analysis improves epigenotype-phenotype correlations in Beckwith-Wiedemann syndrome

    Science.gov (United States)

    Calvello, Mariarosaria; Tabano, Silvia; Colapietro, Patrizia; Maitz, Silvia; Pansa, Alessandra; Augello, Claudia; Lalatta, Faustina; Gentilin, Barbara; Spreafico, Filippo; Calzari, Luciano; Perotti, Daniela; Larizza, Lidia; Russo, Silvia; Selicorni, Angelo; Sirchia, Silvia M; Miozzo, Monica

    2013-01-01

    Beckwith-Wiedemann syndrome (BWS) is a rare disorder characterized by overgrowth and predisposition to embryonal tumors. BWS is caused by various epigenetic and/or genetic alterations that dysregulate the imprinted genes on chromosome region 11p15.5. Molecular analysis is required to reinforce the clinical diagnosis of BWS and to identify BWS patients with cancer susceptibility. This is particularly crucial prenatally because most signs of BWS cannot be recognized in utero. We established a reliable molecular assay by pyrosequencing to quantitatively evaluate the methylation profiles of ICR1 and ICR2. We explored epigenotype-phenotype correlations in 19 patients that fulfilled the clinical diagnostic criteria for BWS, 22 patients with suspected BWS, and three fetuses with omphalocele. Abnormal methylation was observed in one prenatal case and 19 postnatal cases, including seven suspected BWS. Seven cases showed ICR1 hypermethylation, five cases showed ICR2 hypomethylation, and eight cases showed abnormal methylation of ICR1 and ICR2 indicating paternal uniparental disomy (UPD). More cases of ICR1 alterations and UPD were found than expected. This is likely due to the sensitivity of this approach, which can detect slight deviations in methylation from normal levels. There was a significant correlation (p < 0.001) between the percentage of ICR1 methylation and BWS features: severe hypermethylation (range: 75–86%) was associated with macroglossia, macrosomia, and visceromegaly, whereas mild hypermethylation (range: 55–59%) was associated with umbilical hernia and diastasis recti. Evaluation of ICR1 and ICR2 methylation by pyrosequencing in BWS can improve epigenotype-phenotype correlations, detection of methylation alterations in suspected cases, and identification of UPD. PMID:23917791

  14. Protection by quercetin and quercetin-rich fruit juice against induction of oxidative DNA damage and formation of BPDE-DNA adducts in human lymphocytes

    NARCIS (Netherlands)

    Wilms, L.C.; Hollman, P.C.H.; Boots, A.W.; Kleinjans, J.C.S.

    2005-01-01

    Flavonoids are claimed to protect against cardiovascular disease, certain forms of cancer and ageing, possibly by preventing initial DNA damage. Therefore, we investigated the protective effects of the flavonoid quercetin against the formation of oxidative DNA damage and bulky DNA adducts in human

  15. Human DNA polymerase delta double-mutant D316A;E318A interferes with DNA mismatch repair in vitro

    DEFF Research Database (Denmark)

    Liu, Dekang; Frederiksen, Jane H; Liberti, Sascha E

    2017-01-01

    DNA mismatch repair (MMR) is a highly-conserved DNA repair mechanism, whose primary role is to remove DNA replication errors preventing them from manifesting as mutations, thereby increasing the overall genome stability. Defects in MMR are associated with increased cancer risk in humans and other...

  16. Quantitation of human milk proteins and their glycoforms using multiple reaction monitoring (MRM).

    Science.gov (United States)

    Huang, Jincui; Kailemia, Muchena J; Goonatilleke, Elisha; Parker, Evan A; Hong, Qiuting; Sabia, Rocchina; Smilowitz, Jennifer T; German, J Bruce; Lebrilla, Carlito B

    2017-01-01

    Human milk plays a substantial role in the child growth, development and determines their nutritional and health status. Despite the importance of the proteins and glycoproteins in human milk, very little quantitative information especially on their site-specific glycosylation is known. As more functions of milk proteins and other components continue to emerge, their fine-detailed quantitative information is becoming a key factor in milk research efforts. The present work utilizes a sensitive label-free MRM method to quantify seven milk proteins (α-lactalbumin, lactoferrin, secretory immunoglobulin A, immunoglobulin G, immunoglobulin M, α1-antitrypsin, and lysozyme) using their unique peptides while at the same time, quantifying their site-specific N-glycosylation relative to the protein abundance. The method is highly reproducible, has low limit of quantitation, and accounts for differences in glycosylation due to variations in protein amounts. The method described here expands our knowledge about human milk proteins and provides vital details that could be used in monitoring the health of the infant and even the mother. Graphical Abstract The glycopeptides EICs generated from QQQ.

  17. Cadmium Chloride Induces DNA Damage and Apoptosis of Human Liver Carcinoma Cells via Oxidative Stress

    National Research Council Canada - National Science Library

    Skipper, Anthony; Sims, Jennifer N; Yedjou, Clement G; Tchounwou, Paul B

    2016-01-01

    ... mechanisms of action are not fully elucidated. In this research, we hypothesized that oxidative stress plays a key role in cadmium chloride-induced toxicity, DNA damage, and apoptosis of human liver carcinoma (HepG₂) cells...

  18. DNA methylation and transcriptional trajectories during human development and reprogramming of isogenic pluripotent stem cells

    NARCIS (Netherlands)

    Roost, Matthias S; Slieker, Roderick C; Bialecka, Monika; van Iperen, Liesbeth; Gomes Fernandes, Maria M; He, Nannan; Suchiman, H Eka D; Szuhai, Karoly; Carlotti, Françoise; de Koning, Eelco J P; Mummery, Christine L; Heijmans, Bastiaan T; Chuva de Sousa Lopes, Susana M

    2017-01-01

    Determining cell identity and maturation status of differentiated pluripotent stem cells (PSCs) requires knowledge of the transcriptional and epigenetic trajectory of organs during development. Here, we generate a transcriptional and DNA methylation atlas covering 21 organs during human fetal

  19. The Conjugative Relaxase TrwC Promotes Integration of Foreign DNA in the Human Genome.

    Science.gov (United States)

    González-Prieto, Coral; Gabriel, Richard; Dehio, Christoph; Schmidt, Manfred; Llosa, Matxalen

    2017-06-15

    Bacterial conjugation is a mechanism of horizontal DNA transfer. The relaxase TrwC of the conjugative plasmid R388 cleaves one strand of the transferred DNA at the oriT gene, covalently attaches to it, and leads the single-stranded DNA (ssDNA) into the recipient cell. In addition, TrwC catalyzes site-specific integration of the transferred DNA into its target sequence present in the genome of the recipient bacterium. Here, we report the analysis of the efficiency and specificity of the integrase activity of TrwC in human cells, using the type IV secretion system of the human pathogen Bartonella henselae to introduce relaxase-DNA complexes. Compared to Mob relaxase from plasmid pBGR1, we found that TrwC mediated a 10-fold increase in the rate of plasmid DNA transfer to human cells and a 100-fold increase in the rate of chromosomal integration of the transferred DNA. We used linear amplification-mediated PCR and plasmid rescue to characterize the integration pattern in the human genome. DNA sequence analysis revealed mostly reconstituted oriT sequences, indicating that TrwC is active and recircularizes transferred DNA in human cells. One TrwC-mediated site-specific integration event was detected, proving that TrwC is capable of mediating site-specific integration in the human genome, albeit with very low efficiency compared to the rate of random integration. Our results suggest that TrwC may stabilize the plasmid DNA molecules in the nucleus of the human cell, probably by recircularization of the transferred DNA strand. This stabilization would increase the opportunities for integration of the DNA by the host machinery.IMPORTANCE Different biotechnological applications, including gene therapy strategies, require permanent modification of target cells. Long-term expression is achieved either by extrachromosomal persistence or by integration of the introduced DNA. Here, we studied the utility of conjugative relaxase TrwC, a bacterial protein with site

  20. Roles of the human Rad51 L1 and L2 loops in DNA binding.

    Science.gov (United States)

    Matsuo, Yusuke; Sakane, Isao; Takizawa, Yoshimasa; Takahashi, Masayuki; Kurumizaka, Hitoshi

    2006-07-01

    The human Rad51 protein, a eukaryotic ortholog of the bacterial RecA protein, is a key enzyme that functions in homologous recombination and recombinational repair of double strand breaks. The Rad51 protein contains two flexible loops, L1 and L2, which are proposed to be sites for DNA binding, based on a structural comparison with RecA. In the present study, we performed mutational and fluorescent spectroscopic analyses on the L1 and L2 loops to examine their role in DNA binding. Gel retardation and DNA-dependent ATP hydrolysis measurements revealed that the substitution of the tyrosine residue at position 232 (Tyr232) within the L1 loop with alanine, a short side chain amino acid, significantly decreased the DNA-binding ability of human Rad51, without affecting the protein folding or the salt-induced, DNA-independent ATP hydrolysis. Even the conservative replacement with tryptophan affected the DNA binding, indicating that Tyr232 is involved in DNA binding. The importance of the L1 loop was confirmed by the fluorescence change of a tryptophan residue, replacing the Asp231, Ser233, or Gly236 residue, upon DNA binding. The alanine replacement of phenylalanine at position 279 (Phe279) within the L2 loop did not affect the DNA-binding ability of human Rad51, unlike the Phe203 mutation of the RecA L2 loop. The Phe279 side chain may not be directly involved in the interaction with DNA. However, the fluorescence intensity of the tryptophan replacing the Rad51-Phe279 residue was strongly reduced upon DNA binding, indicating that the L2 loop is also close to the DNA-binding site.

  1. Reconstructing long-term human impacts on plant communities: an ecological approach based on lake sediment DNA.

    Science.gov (United States)

    Pansu, Johan; Giguet-Covex, Charline; Ficetola, Gentile Francesco; Gielly, Ludovic; Boyer, Frédéric; Zinger, Lucie; Arnaud, Fabien; Poulenard, Jérôme; Taberlet, Pierre; Choler, Philippe

    2015-04-01

    Paleoenvironmental studies are essential to understand biodiversity changes over long timescales and to assess the relative importance of anthropogenic and environmental factors. Sedimentary ancient DNA (sedaDNA) is an emerging tool in the field of paleoecology and has proven to be a complementary approach to the use of pollen and macroremains for investigating past community changes. SedaDNA-based reconstructions of ancient environments often rely on indicator taxa or expert knowledge, but quantitative ecological analyses might provide more objective information. Here, we analysed sedaDNA to investigate plant community trajectories in the catchment of a high-elevation lake in the Alps over the last 6400 years. We combined data on past and present plant species assemblages along with sedimentological and geochemical records to assess the relative impact of human activities through pastoralism, and abiotic factors (temperature and soil evolution). Over the last 6400 years, we identified significant variation in plant communities, mostly related to soil evolution and pastoral activities. An abrupt vegetational change corresponding to the establishment of an agropastoral landscape was detected during the Late Holocene, approximately 4500 years ago, with the replacement of mountain forests and tall-herb communities by heathlands and grazed lands. Our results highlight the importance of anthropogenic activities in mountain areas for the long-term evolution of local plant assemblages. SedaDNA data, associated with other paleoenvironmental proxies and present plant assemblages, appear to be a relevant tool for reconstruction of plant cover history. Their integration, in conjunction with classical tools, offers interesting perspectives for a better understanding of long-term ecosystem dynamics under the influence of human-induced and environmental drivers. © 2015 John Wiley & Sons Ltd.

  2. Quantitative evaluation of impedance perception characteristics of humans in the man-machine interface

    Energy Technology Data Exchange (ETDEWEB)

    Onish, Keiichi [Yamaha Motor Co., Shizuoka (Japan); Kim, Young Woo [Daegu Techno Park R and D Center, Seoul (Korea, Republic of); Obinata, Goro [Nagoya University, Nagoya (Japan); Hase, Kazunori [Tokyo Metropolitan University, Tokyo (Japan)

    2013-05-15

    We investigated impedance perception characteristics of humans in the man-machine interface. Sensibility or operational feel about physical properties of machine dynamics is obtained through perception process. We evaluated the impedance perception characteristics of humans who are operating a mechanical system, based on extended Scheffe's subjective evaluation method in full consideration of the influence of impedance level, impedance difference, experiment order, individual difference and so on. Constant method based quantitative evaluation was adopted to investigate the influence of motion frequency and change of the impedance on human impedance perception characteristics. Experimental results indicate that humans perceive impedance of mechanical systems based on comparison process of the dynamical characteristics of the systems. The proposed method can be applied to quantify the design requirement of man-machine interface. The effectiveness of the proposed method is verified through experimental results.

  3. Comparative Analysis of Whey N-Glycoproteins in Human Colostrum and Mature Milk Using Quantitative Glycoproteomics.

    Science.gov (United States)

    Cao, Xueyan; Song, Dahe; Yang, Mei; Yang, Ning; Ye, Qing; Tao, Dongbing; Liu, Biao; Wu, Rina; Yue, Xiqing

    2017-11-29

    Glycosylation is a ubiquitous post-translational protein modification that plays a substantial role in various processes. However, whey glycoproteins in human milk have not been completely profiled. Herein, we used quantitative glycoproteomics to quantify whey N-glycosylation sites and their alteration in human milk during lactation; 110 N-glycosylation sites on 63 proteins and 91 N-glycosylation sites on 53 proteins were quantified in colostrum and mature milk whey, respectively. Among these, 68 glycosylation sites on 38 proteins were differentially expressed in human colostrum and mature milk whey. These differentially expressed N-glycoproteins were highly enriched in "localization", "extracellular region part", and "modified amino acid binding" according to gene ontology annotation and mainly involved in complement and coagulation cascades pathway. These results shed light on the glycosylation sites, composition and biological functions of whey N-glycoproteins in human colostrum and mature milk, and provide substantial insight into the role of protein glycosylation during infant development.

  4. A quantitative assessment of the Hadoop framework for analyzing massively parallel DNA sequencing data.

    Science.gov (United States)

    Siretskiy, Alexey; Sundqvist, Tore; Voznesenskiy, Mikhail; Spjuth, Ola

    2015-01-01

    New high-throughput technologies, such as massively parallel sequencing, have transformed the life sciences into a data-intensive field. The most common e-infrastructure for analyzing this data consists of batch systems that are based on high-performance computing resources; however, the bioinformatics software that is built on this platform does not scale well in the general case. Recently, the Hadoop platform has emerged as an interesting option to address the challenges of increasingly large datasets with distributed storage, distributed processing, built-in data locality, fault tolerance, and an appealing programming methodology. In this work we introduce metrics and report on a quantitative comparison between Hadoop and a single node of conventional high-performance computing resources for the tasks of short read mapping and variant calling. We calculate efficiency as a function of data size and observe that the Hadoop platform is more efficient for biologically relevant data sizes in terms of computing hours for both split and un-split data files. We also quantify the advantages of the data locality provided by Hadoop for NGS problems, and show that a classical architecture with network-attached storage will not scale when computing resources increase in numbers. Measurements were performed using ten datasets of different sizes, up to 100 gigabases, using the pipeline implemented in Crossbow. To make a fair comparison, we implemented an improved preprocessor for Hadoop with better performance for splittable data files. For improved usability, we implemented a graphical user interface for Crossbow in a private cloud environment using the CloudGene platform. All of the code and data in this study are freely available as open source in public repositories. From our experiments we can conclude that the improved Hadoop pipeline scales better than the same pipeline on high-performance computing resources, we also conclude that Hadoop is an economically viable

  5. Detection of DNA damage by space radiation in human fibroblasts flown on the International Space Station

    Science.gov (United States)

    Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis; Karouia, Fathi; Wu, Honglu

    2017-02-01

    Although charged particles in space have been detected with radiation detectors on board spacecraft since the discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation is challenging due to the low dose and low dose rate nature of the radiation environment, and due to the difficulty in distinguishing the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in their lymphocytes and early onset of cataracts, are attributed primarily to their exposure to space radiation. In this study, cultured human fibroblasts were flown on the International Space Station (ISS). Cells were kept at 37 °C in space for 14 days before being fixed for analysis of DNA damage with the γ-H2AX assay. The 3-dimensional γ-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed several foci that were larger and displayed a track pattern only in the Day 14 flight samples. To confirm that the foci data from the flight study was actually induced from space radiation exposure, cultured human fibroblasts were exposed to low dose rate γ rays at 37 °C. Cells exposed to chronic γ rays showed similar foci size distribution in comparison to the non-exposed controls. The cells were also exposed to low- and high-LET protons, and high-LET Fe ions on the ground. Our results suggest that in G1 human fibroblasts under the normal culture condition, only a small fraction of large size foci can be attributed to high-LET radiation in space.

  6. Detection of DNA Damage by Space Radiation in Human Fibroblasts Flown on the International Space Station

    Science.gov (United States)

    Lu, Tao; Zhang, Ye; Wong, Michael; Feiveson, Alan; Gaza, Ramona; Stoffle, Nicholas; Wang, Huichen; Wilson, Bobby; Rohde, Larry; Stodieck, Louis; hide

    2017-01-01

    Although charged particles in space have been detected with radiation detectors on board spacecraft since the discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation is challenging due to the low dose and low dose rate nature of the radiation environment, and due to the difficulty in distinguishing the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in their lymphocytes and early onset of cataracts, are attributed primarily to their exposure to space radiation. In this study, cultured human fibroblasts were flown on the International Space Station (ISS). Cells were kept at 37 degrees Centigrade in space for 14 days before being fixed for analysis of DNA damages with the gamma-H2AX assay. The 3-dimensional gamma-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed several foci that were larger and displayed a track pattern only in the Day 14 flight samples. To confirm that the foci data from the flight study was actually induced from space radiation exposure, cultured human fibroblasts were exposed to low dose rate gamma rays at 37 degrees Centigrade. Cells exposed to chronic gamma rays showed similar foci size distribution in comparison to the non-exposed controls. The cells were also exposed to low- and high-LET (Linear Energy Transfer) protons, and high-LET Fe ions on the ground. Our results suggest that in G1 human fibroblasts under the normal culture condition, only a small fraction of large size foci can be attributed to high-LET radiation in space.

  7. Development of a traceable molecular hygiene control method (TMHCM) for human DNA content in foods.

    Science.gov (United States)

    Şakalar, Ergün; Ergün, Şeyma Özçirak; Pala, Çiğdem; Akar, Emine; Ataşoğlu, Cengiz

    2017-06-15

    The aim of this study was to develop a molecular technique to determine the level of human originated DNA contamination in unhygienic food products. In the study, four model foods were prepared under both hygienic (H) and non-hygienic (NH) conditions and the human originated microbial loads of these products were determined. DNA was extracted from the model foods and human buccal samples by GIDAGEN Multi-fast DNA isolation kit. A primer specific region of human mitochondrial D-Loop was designed. The level of human DNA contamination in the model foods was determined by real-time PCR. The sensitivity of the technique developed here was 0.00001ng DNA/PCR. In addition, the applicability of the traceable molecular hygiene control method (TMHCM) was tested in 60 food samples from the market. The results of this study demonstrate that DNA based TMHCM can be used to predict to what extent foods meet the human oriented hygienic conditions. Copyright © 2016. Published by Elsevier Ltd.

  8. Identification of person and quantification of human DNA recovered from mosquitoes (Culicidae).

    Science.gov (United States)

    Curic, Goran; Hercog, Rajna; Vrselja, Zvonimir; Wagner, Jasenka

    2014-01-01

    Mosquitoes (Culicidae) are widespread insects and can be important in forensic context as a source of human DNA. In order to establish the quantity of human DNA in mosquitoes' gut after different post-feeding interval and for how long after taking a bloodmeal the human donor could be identified, 174 blood-engorged mosquitoes (subfamily Anophelinae and Culicinae) were captured, kept alive and sacrificed at 8h intervals. Human DNA was amplified using forensic PCR kits (Identifiler, MiniFiler, and Quantifiler). A full DNA profiles were obtained from all Culicinae mosquitoes (74/74) up to 48 h and profiling was successful up to 88 h after a bloodmeal. Duration of post-feeding interval had a significant negative effect on the possibility of obtaining a full profile (pmosquitoes are a suitable source of human DNA for forensic STR kits more than three days after a bloodmeal. Human DNA recovered from mosquito can be used for matching purposes and could be useful in revealing spatial and temporal relation of events that took place at the crime scene. Therefore, mosquitoes at the crime scene, dead or alive, could be a valuable piece of forensic evidence. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  9. Detecting the quantitative hydrological response under the climate change and human activities

    Science.gov (United States)

    Wu, J.

    2016-12-01

    Understanding and separating the relative contributions of climate change and human activities on runoff variations are very important for regional water resources management and sustainable water resources utilizations. Thus the methods of distinguishing the contributions of climate change and human activities on runoff changes are of vital importance. In this study, we systematically analyzed the respective characteristics and relative advantages and disadvantages of common used quantitative methods involving empirically statistical methods (e.g. a double mass curve and a simple linear regression), elasticity-based methods (e.g., six Budyko-based model and a nonparametric method) and hydrological modeling method (e.g. The Soil and Water Assessment Tool (SWAT) model). We also estimated applications of these quantitative methods in global scale. In addition, Yanhe River Basin as a specific case study was employed to separate the impacts of climate change and human activities on runoff changes, the result showed climate change played a more important role in runoff changes, which estimated to be about 46.1% 60.8% (average 54.1%) of the total runoff decrease, whereas the effect of human activities on runoff reduction accounted for about 39.1% 53.9% (average 45.9%). Furthermore, we evaluated discrepancies, uncertainties and availability of these quantitative methods. The results revealed elasticity-based methods and hydrological modeling method consistently effectively distinguished the contributions of climate change and human activities on runoff changes, while empirically statistical methods had a big difference with other two types in distinguishing the contributions. It also showed empirically statistical methods were not suitable for the area which posed a relative poorer runoff coefficient in the baseline period, whereas both elasticity-based methods and hydrological modeling method could be employed with few restrictions.

  10. DNA Damage Reduces the Quality, but Not the Quantity of Human Papillomavirus 16 E1 and E2 DNA Replication

    Directory of Open Access Journals (Sweden)

    Molly L. Bristol

    2016-06-01

    Full Text Available Human papillomaviruses (HPVs are causative agents in almost all cervical carcinomas. HPVs are also causative agents in head and neck cancer, the cases of which are increasing rapidly. Viral replication activates the DNA damage response (DDR pathway; associated proteins are recruited to replication foci, and this pathway may serve to allow for viral genome amplification. Likewise, HPV genome double-strand breaks (DSBs could be produced during replication and could lead to linearization and viral integration. Many studies have shown that viral integration into the host genome results in unregulated expression of the viral oncogenes, E6 and E7, promoting HPV-induced carcinogenesis. Previously, we have demonstrated that DNA-damaging agents, such as etoposide, or knocking down viral replication partner proteins, such as topoisomerase II β binding protein I (TopBP1, does not reduce the level of DNA replication. Here, we investigated whether these treatments alter the quality of DNA replication by HPV16 E1 and E2. We confirm that knockdown of TopBP1 or treatment with etoposide does not reduce total levels of E1/E2-mediated DNA replication; however, the quality of replication is significantly reduced. The results demonstrate that E1 and E2 continue to replicate under genomically-stressed conditions and that this replication is mutagenic. This mutagenesis would promote the formation of substrates for integration of the viral genome into that of the host, a hallmark of cervical cancer.

  11. DNA Damage Reduces the Quality, but Not the Quantity of Human Papillomavirus 16 E1 and E2 DNA Replication.

    Science.gov (United States)

    Bristol, Molly L; Wang, Xu; Smith, Nathan W; Son, Minkyeong P; Evans, Michael R; Morgan, Iain M

    2016-06-22

    Human papillomaviruses (HPVs) are causative agents in almost all cervical carcinomas. HPVs are also causative agents in head and neck cancer, the cases of which are increasing rapidly. Viral replication activates the DNA damage response (DDR) pathway; associated proteins are recruited to replication foci, and this pathway may serve to allow for viral genome amplification. Likewise, HPV genome double-strand breaks (DSBs) could be produced during replication and could lead to linearization and viral integration. Many studies have shown that viral integration into the host genome results in unregulated expression of the viral oncogenes, E6 and E7, promoting HPV-induced carcinogenesis. Previously, we have demonstrated that DNA-damaging agents, such as etoposide, or knocking down viral replication partner proteins, such as topoisomerase II β binding protein I (TopBP1), does not reduce the level of DNA replication. Here, we investigated whether these treatments alter the quality of DNA replication by HPV16 E1 and E2. We confirm that knockdown of TopBP1 or treatment with etoposide does not reduce total levels of E1/E2-mediated DNA replication; however, the quality of replication is significantly reduced. The results demonstrate that E1 and E2 continue to replicate under genomically-stressed conditions and that this replication is mutagenic. This mutagenesis would promote the formation of substrates for integration of the viral genome into that of the host, a hallmark of cervical cancer.

  12. Comparison of DNA extraction methods for human gut microbial community profiling.

    Science.gov (United States)

    Lim, Mi Young; Song, Eun-Ji; Kim, Sang Ho; Lee, Jangwon; Nam, Young-Do

    2017-12-21

    The human gut harbors a vast range of microbes that have significant impact on health and disease. Therefore, gut microbiome profiling holds promise for use in early diagnosis and precision medicine development. Accurate profiling of the highly complex gut microbiome requires DNA extraction methods that provide sufficient coverage of the original community as well as adequate quality and quantity. We tested nine different DNA extraction methods using three commercial kits (TianLong Stool DNA/RNA Extraction Kit (TS), QIAamp DNA Stool Mini Kit (QS), and QIAamp PowerFecal DNA Kit (QP)) with or without additional bead-beating step using manual or automated methods and compared them in terms of DNA extraction ability from human fecal sample. All methods produced DNA in sufficient concentration and quality for use in sequencing, and the samples were clustered according to the DNA extraction method. Inclusion of bead-beating step especially resulted in higher degrees of microbial diversity and had the greatest effect on gut microbiome composition. Among the samples subjected to bead-beating method, TS kit samples were more similar to QP kit samples than QS kit samples. Our results emphasize the importance of mechanical disruption step for a more comprehensive profiling of the human gut microbiome. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  13. Human DNA repair disorders in dermatology: A historical perspective, current concepts and new insight.

    Science.gov (United States)

    Moriwaki, Shinichi

    2016-02-01

    Products of DNA damage, such as cyclobutane pyrimidine dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4 PPs), are continually formed in genomes after exposure to UV radiation. When these DNA damages remain unrepaired in essential DNA sites for prolonged periods, DNA replication and transcription are hampered or mutation is induced, which may cause cell death, cellular senescence, and carcinogenesis of the skin. To protect against such UV-induced DNA damage, living organisms nicely retain "DNA repair systems", which can efficiently repair "harmful" DNA damage through precise mechanisms by the integrated functions of many proteins. In humans, the failure of DNA repair systems causes a variety of disorders. Dermatological conditions such as hereditary photodermatoses, xeroderma pigmentosum (XP) and Cockayne syndrome (CS) are caused by congenital functional defects in the nucleotide excision repair (NER) system or the translesion synthesis (TLS) system. In this review, we describe the historical progress, recent findings, and future prospects of studies of human diseases associated with DNA-repair defects. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. The RNA splicing factor ASF/SF2 inhibits human topoisomerase I mediated DNA relaxation

    DEFF Research Database (Denmark)

    Andersen, Félicie Faucon; Tange, Thomas Ø.; Sinnathamby, Thayaline

    2002-01-01

    Human topoisomerase I interacts with and phosphorylates the SR-family of RNA splicing factors, including ASF/SF2, and has been suggested to play an important role in the regulation of RNA splicing. Here we present evidence to support the theory that the regulation can go the other way around...... with the SR-proteins controlling topoisomerase I DNA activity. We demonstrate that the splicing factor ASF/SF2 inhibits relaxation by interfering with the DNA cleavage and/or DNA binding steps of human topoisomerase I catalysis. The inhibition of relaxation correlated with the ability of various deletion...

  15. DNA topoisomerases and the DNA lesion in human genetic instability syndromes.

    Science.gov (United States)

    Poot, M; Hoehn, H

    1993-04-01

    Genetically determined chromosomal instability entails, among other sequelae, a condition of elevated cancer risk. Patients with the autosomal recessive disorder Fanconi's anemia (FA) often develop leukemias of the monocytic lineage together with pancytopenia, whereas the Bloom's syndrome (BS) mutation confers an early and elevated incidence of neoplasia of no particular type. Cultured cells from FA patients show spontaneously elevated rates of chromosome aberrations and a hypersensitivity to DNA cross-linking agents. Cytogenetic evaluation of cells from BS patients revealed elevated rates of sister chromatid exchanges, which were sensitive to the bromodeoxyuridine (BrdU) concentration used in the assay. Such a BrdU sensitivity was also found in cultured cells from healthy subjects exposed to the intracellular superoxide generator paraquat or to bleomycin. Skin fibroblasts from FA and BS patients show poor growth, which in the case of FA could be mitigated by lowering the oxygen concentration to 5%. Lymphoblastoid B-cell lines derived from peripheral blood samples from FA and BS patients show elevated numbers of cells arrested in the G2 phase of the cell cycle. This phenomenon could also be provoked by exposing cell lines from healthy subjects to compounds interfering with the function of DNA topoisomerase I (camptothecin) or II (m-AMSA). To test for a putative deficiency of either DNA topoisomerase, B-cell cultures from FA and BS patients were compared with cell cultures from healthy subjects regarding their sensitivity towards camptothecin and m-AMSA. No difference in sensitivity to these agents was found in patient vs. control cell lines, thus ruling out a deficiency in DNA topoisomerase I or II as the prime defect in these conditions of elevated cancer risk. The similarity between the cell cycle kinetic patterns found in untreated FA cell lines and in normal cell lines exposed to camptothecin or m-AMSA suggest that the DNA lesion in FA, presumably being caused

  16. Recombinant DNA risk assessment studies in humans: efficacy of poorly mobilizable plasmids in biologic containment.

    Science.gov (United States)

    Levine, M M; Kaper, J B; Lockman, H; Black, R E; Clements, M L; Falkow, S

    1983-10-01

    Recombinant DNA risk assessment studies quantitated the mobilizability of "safe" plasmid pBR325, in comparison with readily mobilizable plasmid pJBK5 (chloramphenicol and tetracycline resistant). Of 15 volunteers who became colonized after ingestion of 5 X 10(10) Escherichia coli HS-4, a normal human flora strain containing pJBK5 and daily oral tetracycline, nine manifested transfer of pJBK5 to normal flora by means of triparental mating. In contrast, none of 12 other volunteers cocolonized with HS-4 bearing "safe" pBR325 and normal flora showed transfer (P = 0.001), despite ingestion of tetracycline. To accomplish transfer directly, E coli HS-4 containing both pBR325 and a derepressed, conjugative plasmid (F-amp) was fed to two groups of volunteers. Transfer of pBR325 to normal flora occurred in 13 of 18 volunteers taking daily tetracycline but in none of eight who did not (P less than 0.002). Nor were transconjugants detected, despite tetracycline ingestion, in five volunteers who ingested and excreted E coli K12 (pBR325 plus F-amp).

  17. Age and metabolic risk factors associated with oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise

    2015-01-01

    Aging is associated with oxidative stress-generated damage to DNA and this could be related to metabolic disturbances. This study investigated the association between levels of oxidatively damaged DNA in peripheral blood mononuclear cells (PBMCs) and metabolic risk factors in 1,019 subjects, aged...... 18-93 years. DNA damage was analyzed as strand breaks by the comet assay and levels of formamidopyrimidine (FPG-) and human 8-oxoguanine DNA glycosylase 1 (hOGG1)-sensitive sites There was an association between age and levels of FPG-sensitive sites for women, but not for men. The same tendency...... was observed for the level of hOGG1-sensitive sites, whereas there was no association with the level of strand breaks. The effect of age on oxidatively damaged DNA in women disappeared in multivariate models, which showed robust positive associations between DNA damage and plasma levels of triglycerides...

  18. Seasonal variations of DNA damage in human lymphocytes: Correlation with different environmental variables

    Energy Technology Data Exchange (ETDEWEB)

    Giovannelli, Lisa [Dipartimento di Farmacologia Preclinica e Clinica, Universita di Firenze, Viale Pieraccini 6, 50139 Florence (Italy)]. E-mail: lisa.giovannelli@unifi.it; Pitozzi, Vanessa [Dipartimento di Farmacologia Preclinica e Clinica, Universita di Firenze, Viale Pieraccini 6, 50139 Florence (Italy); Moretti, Silvia [Department of Dermatological Sciences, University of Florence, Florence (Italy); Boddi, Vieri [Department of Public Health, University of Florence, Florence (Italy); Dolara, Piero [Dipartimento di Farmacologia Preclinica e Clinica, Universita di Firenze, Viale Pieraccini 6, 50139 Florence (Italy)

    2006-01-29

    Several types of DNA damage, including DNA breaks and DNA base oxidation, display a seasonal trend. In the present work, a sample of 79 healthy subjects living in the city of Florence, Italy, was used to analyse this effect. Three possible causative agents were taken into consideration: solar radiation, air temperature and air ozone level. DNA damage was measured in isolated human lymphocytes at different times during the year and the observed damage was correlated with the levels of these three agents in the days preceding blood sampling. Three time windows were chosen: 3, 7 and 30 days before blood sampling. DNA strand breaks and the oxidized purinic bases cleaved by the formamidopyrimidine glycosylase (FPG sites) were measured by means of the comet assay. The results of multivariate regression analysis showed a positive correlation between lymphocyte DNA damage and air temperature, and a less strong correlation with global solar radiation and air ozone levels.

  19. Preliminary perspectives on DNA collection in anti-human trafficking efforts.

    Science.gov (United States)

    Katsanis, Sara H; Kim, Joyce; Minear, Mollie A; Chandrasekharan, Subhashini; Wagner, Jennifer K

    2014-01-01

    Forensic DNA methodologies have potential applications in the investigation of human trafficking cases. DNA and relationship testing may be useful for confirmation of biological relationship claims in immigration, identification of trafficked individuals who are missing persons, and family reunification of displaced individuals after mass disasters and conflicts. As these applications rely on the collection of DNA from non-criminals and potentially vulnerable individuals, questions arise as to how to address the ethical challenges of collection, security, and privacy of collected samples and DNA profiles. We administered a survey targeted to victims' advocates to gain preliminary understanding of perspectives regarding human trafficking definitions, DNA and sex workers, and perceived trust of authorities potentially involved in DNA collection. We asked respondents to consider the use of DNA for investigating adoption fraud, sex trafficking, and post-conflict child soldier cases. We found some key differences in perspectives on defining what qualifies as "trafficking." When we varied terminology between "sex worker" and "sex trafficking victim" we detected differences in perception on which authorities can be trusted. Respondents were supportive of the hypothetical models proposed to collect DNA. Most were favorable of DNA specimens being controlled by an authority outside of law enforcement. Participants voiced concerns focused on privacy, misuse of DNA samples and data, unintentional harms, data security, and infrastructure. These preliminary data indicate that while there is perceived value in programs to use DNA for investigating cases of human trafficking, these programs may need to consider levels of trust in authorities as their logistics are developed and implemented.

  20. A novel method to capture methylated human DNA from stool: implications for colorectal cancer screening.

    Science.gov (United States)

    Zou, Hongzhi; Harrington, Jonathan; Rego, Rafaela L; Ahlquist, David A

    2007-09-01

    Assay of methylated DNA markers in stool is a promising approach for colorectal cancer (CRC) screening. A method to capture hypermethylated CpG islands from stool would enrich target analyte and allow optimal assay sensitivity. Methyl-binding domain (MBD) protein was produced using a pET6HMBD plasmid with MBD DNA sequence cloned from rat MeCP2 gene and bound to a column of nickel-agarose resin. We first established the feasibility of using the MBD column to extract methylated human DNA in a high background of fecal bacterial DNA. To explore the impact of MBD enrichment on detection sensitivity, the tumor-associated methylated vimentin gene was assayed with methylation-specific PCR from stools to which low amounts of cancer cell DNA (0-50 ng) were added and from stools from CRC patients and healthy individuals. Stools from cancer patients were selected with low amounts of human DNA (median 7 ng, range 0.5-832 ng). With MBD enrichment, methylated vimentin was detected in stools enriched with >/=10 ng of cancer cell DNA and in CRC stool with a range of native human DNA amounts from 4 to 832 ng. Without MBD enrichment, methylated vimentin was not detected in the enriched stools and was detected in only 1 cancer stool with high human DNA (832 ng). In stools from healthy individuals methylated vimentin was not detected, with or without MBD enrichment. MBD capture increases assay sensitivity for detecting methylated DNA markers in stool. Applied clinical studies for stool cancer screening are indicated.

  1. Sources of Technical Variability in Quantitative LC-MS Proteomics: Human Brain Tissue Sample Analysis.

    Energy Technology Data Exchange (ETDEWEB)

    Piehowski, Paul D.; Petyuk, Vladislav A.; Orton, Daniel J.; Xie, Fang; Moore, Ronald J.; Ramirez Restrepo, Manuel; Engel, Anzhelika; Lieberman, Andrew P.; Albin, Roger L.; Camp, David G.; Smith, Richard D.; Myers, Amanda J.

    2013-05-03

    To design a robust quantitative proteomics study, an understanding of both the inherent heterogeneity of the biological samples being studied as well as the technical variability of the proteomics methods and platform is needed. Additionally, accurately identifying the technical steps associated with the largest variability would provide valuable information for the improvement and design of future processing pipelines. We present an experimental strategy that allows for a detailed examination of the variability of the quantitative LC-MS proteomics measurements. By replicating analyses at different stages of processing, various technical components can be estimated and their individual contribution to technical variability can be dissected. This design can be easily adapted to other quantitative proteomics pipelines. Herein, we applied this methodology to our label-free workflow for the processing of human brain tissue. For this application, the pipeline was divided into four critical components: Tissue dissection and homogenization (extraction), protein denaturation followed by trypsin digestion and SPE clean-up (digestion), short-term run-to-run instrumental response fluctuation (instrumental variance), and long-term drift of the quantitative response of the LC-MS/MS platform over the 2 week period of continuous analysis (instrumental stability). From this analysis, we found the following contributions to variability: extraction (72%) >> instrumental variance (16%) > instrumental stability (8.4%) > digestion (3.1%). Furthermore, the stability of the platform and its’ suitability for discovery proteomics studies is demonstrated.

  2. Preferential mitochondrial DNA injury caused by glucose oxidase as a steady generator of hydrogen peroxide in human fibroblasts.

    Science.gov (United States)

    Salazar, J J; Van Houten, B

    1997-11-01

    To test the hypothesis that mitochondrial DNA (mtDNA) is more prone to reactive oxygen species (ROS) damage than nuclear DNA, a continuous flux of hydrogen peroxide (H2O2) was produced with the glucose/glucose oxidase system. Using a horse radish peroxidase (HRPO)-based colorimetric assay to detect H2O2, glucose oxidase (GO; 12 mU/ml) produced 95 microM of H2O2 in 1 h, whereas only 46 microM of hydrogen peroxide accumulated in the presence of SV40-transformed human fibroblasts ( approximately 1 x 10(6). DNA damage was assessed in the mitochondira and three nuclear regions using a quantitative PCR assay. GO (12 mU/ml) resulted in more damage to the mitochondrial DNA (2.250 +/- 0.045 lesions/10 kb) than in any one of three nuclear targets, which included the non-expressed beta-globin locus (0.436 +/- 0.029 lesions/10 kb); and the active DNA polymerase b gene (0.442 +/- 0.037 lesions/10 kb); and the active hprt gene (0.310 +/- 0.025). Damage to the mtDNA occurred within 15 min of GO treatment, whereas nuclear damage did not appear until after 30 min, and reached a maximum after 60 min. Repair of mitochondrial damage after a 15 min GO (6 mU/ml) treatment was examined. Mitochondria repaired 50% of the damage after 1 h, and by 6 h all the damage was repaired. Higher doses of GO-generated H202, or more extended treatment periods, lead to mitochondrial DNA damage which was not repaired. Mitochondrial function was monitored using the MTT (3,(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide) assay. A 15 min treatment with 6 mU/ml of GO decreased mitochondrial activity to 80% of the control; the activity recovered completely within 1 h after damage. These data show that GO-generated H202 causes acute damage to mtDNA and function, and demonstrate that this organelle is an important site for the cellular toxicity of ROS.

  3. Comparing different post-mortem human samples as DNA sources for downstream genotyping and identification.

    Science.gov (United States)

    Calacal, Gayvelline C; Apaga, Dame Loveliness T; Salvador, Jazelyn M; Jimenez, Joseph Andrew D; Lagat, Ludivino J; Villacorta, Renato Pio F; Lim, Maria Cecilia F; Fortun, Raquel D R; Datar, Francisco A; De Ungria, Maria Corazon A

    2015-11-01

    The capability of DNA laboratories to perform genotyping procedures from post-mortem remains, including those that had undergone putrefaction, continues to be a challenge in the Philippines, a country characterized by very humid and warm conditions all year round. These environmental conditions accelerate the decomposition of human remains that were recovered after a disaster and those that were left abandoned after a crime. When considerable tissue decomposition of human remains has taken place, there is no other option but to extract DNA from bone and/or teeth samples. Routinely, femur shafts are obtained from recovered bodies for human identification because the calcium matrix protects the DNA contained in the osteocytes. In the Philippines, there is difficulty in collecting femur samples after natural disasters or even human-made disasters, because these events are usually characterized by a large number of fatalities. Identification of casualties is further delayed by limitation in human and material resources. Hence, it is imperative to test other types of biological samples that are easier to collect, transport, process and store. We analyzed DNA that were obtained from body fluid, bone marrow, muscle tissue, clavicle, femur, metatarsal, patella, rib and vertebral samples from five recently deceased untreated male cadavers and seven male human remains that were embalmed, buried for ∼ 1 month and then exhumed. The bodies had undergone different environmental conditions and were in various stages of putrefaction. A DNA extraction method utilizing a detergent-washing step followed by an organic procedure was used. The utility of bone marrow and vitreous fluid including bone marrow and vitreous fluid that was transferred on FTA(®) cards and subjected to autosomal STR and Y-STR DNA typing were also evaluated. DNA yield was measured and the presence or absence of PCR inhibitors in DNA extracts was assessed using Plexor(®)HY. All samples were amplified using

  4. Outdoor blue spaces, human health and well-being: A systematic review of quantitative studies.

    Science.gov (United States)

    Gascon, Mireia; Zijlema, Wilma; Vert, Cristina; White, Mathew P; Nieuwenhuijsen, Mark J

    2017-11-01

    A growing number of quantitative studies have investigated the potential benefits of outdoor blue spaces (lakes, rivers, sea, etc) and human health, but there is not yet a systematic review synthesizing this evidence. To systematically review the current quantitative evidence on human health and well-being benefits of outdoor blue spaces. Following PRISMA guidelines for reporting systematic reviews and meta-analysis, observational and experimental quantitative studies focusing on both residential and non-residential outdoor blue space exposure were searched using specific keywords. In total 35 studies were included in the current systematic review, most of them being classified as of "good quality" (N=22). The balance of evidence suggested a positive association between greater exposure to outdoor blue spaces and both benefits to mental health and well-being (N=12 studies) and levels of physical activity (N=13 studies). The evidence of an association between outdoor blue space exposure and general health (N=6 studies), obesity (N=8 studies) and cardiovascular (N=4 studies) and related outcomes was less consistent. Although encouraging, there remains relatively few studies and a large degree of heterogeneity in terms of study design, exposure metrics and outcome measures, making synthesis difficult. Further research is needed using longitudinal research and natural experiments, preferably across a broader range of countries, to better understand the causal associations between blue spaces, health and wellbeing. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Human embryonic stem cells have enhanced repair of multiple forms of DNA damage

    DEFF Research Database (Denmark)

    Maynard, Scott; Swistowska, Anna Maria; Lee, Jae Wan

    2008-01-01

    Embryonic stem cells need to maintain genomic integrity so that they can retain the ability to differentiate into multiple cell types without propagating DNA errors. Previous studies have suggested that mechanisms of genome surveillance, including DNA repair, are superior in mouse embryonic stem...... cells compared with various differentiated murine cells. Using single-cell gel electrophoresis (comet assay) we found that human embryonic stem cells (BG01, I6) have more efficient repair of different types of DNA damage (generated from H2O2, UV-C, ionizing radiation, or psoralen) than human primary...... fibroblasts (WI-38, hs27) and, with the exception of UV-C damage, HeLa cells. Microarray gene expression analysis showed that mRNA levels of several DNA repair genes are elevated in human embryonic stem cells compared with their differentiated forms (embryoid bodies). These data suggest that genomic...

  6. Polymorphisms in human DNA repair genes and head and neck ...

    Indian Academy of Sciences (India)

    Sci. USA 97, 9886–9891. Viswanathan H. and Wilson J. A. 2004 Alcohol—the neglected factor in head and neck cancer. Clin. Otolaryngol. 29, 295–300. Vogel U., Hedayati M., Dybdahl M., Grossman L. and Nexo B. A.. 2001 Polymorphisms of the DNA repair gene XPD, correlations with risk of basal cell carcinoma revisited.

  7. DNA Genotype of Human Papilloma Virus Infection among ...

    African Journals Online (AJOL)

    Objective: To determine DNA genotype of HPV infection among adolescent girls at KNH - Youth Clinic and use it as an advocacy tool for the introduction of the HPV vaccine provision in the clinic. Design: Cross-sectional study. Setting: Kenyatta National Hospital Youth clinic. Subjects: Adolescent (and youths) girls aged ...

  8. Detection of human papillomavirus DNA with in situ hybridisation in ...

    African Journals Online (AJOL)

    studied and different methods used in HPV DNA detection. According to the Federation Dentaire Internationa~ intra- oral cancer, of which squamous cell carcinoma accounts for the majority of cases, is the third most common malj§nant disease among men in developing countries.'2 The g'iortality rate remains unacceptably ...

  9. Stability of human telomere quadruplexes at high DNA concentrations.

    Science.gov (United States)

    Kejnovská, Iva; Vorlíčková, Michaela; Brázdová, Marie; Sagi, Janos

    2014-04-01

    For mimicking macromolecular crowding of DNA quadruplexes, various crowding agents have been used, typically PEG, with quadruplexes of micromolar strand concentrations. Thermal and thermodynamic stabilities of these quadruplexes increased with the concentration of the agents, the rise depended on the crowder used. A different phenomenon was observed, and is presented in this article, when the crowder was the quadruplex itself. With DNA strand concentrations ranging from 3 µM to 9 mM, the thermostability did not change up to ∼2 mM, above which it increased, indicating that the unfolding quadruplex units were not monomolecular above ∼2 mM. The results are explained by self-association of the G-quadruplexes above this concentration. The ΔG(°) 37 values, evaluated only below 2 mM, did not become more negative, as with the non-DNA crowders, instead, slightly increased. Folding topology changed from antiparallel to hybrid above 2 mM, and then to parallel quadruplexes at high, 6-9 mM strand concentrations. In this range, the concentration of the DNA phosphate anions approached the concentration of the K(+) counterions used. Volume exclusion is assumed to promote the topological changes of quadruplexes toward the parallel, and the decreased screening of anions could affect their stability. Copyright © 2013 Wiley Periodicals, Inc.

  10. Evaluation of the DNA damaging effects of amitraz on human ...

    Indian Academy of Sciences (India)

    Amitraz is formamidine pesticide widely used as insecticide and acaricide. In veterinary medicine, amitraz has important uses against ticks, mites and lice on animals. Also, amitraz is used in apiculture to control Varroa destructor. It this study, the alkaline Comet assay was used to evaluate DNA damaging effects of amitraz ...

  11. DNA Repair in Human Pluripotent Stem Cells Is Distinct from That in Non-Pluripotent Human Cells

    Science.gov (United States)

    Luo, Li Z.; Park, Sang-Won; Bates, Steven E.; Zeng, Xianmin; Iverson, Linda E.; O'Connor, Timothy R.

    2012-01-01

    The potential for human disease treatment using human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells (iPSCs), also carries the risk of added genomic instability. Genomic instability is most often linked to DNA repair deficiencies, which indicates that screening/characterization of possible repair deficiencies in pluripotent human stem cells should be a necessary step prior to their clinical and research use. In this study, a comparison of DNA repair pathways in pluripotent cells, as compared to those in non-pluripotent cells, demonstrated that DNA repair capacities of pluripotent cell lines were more heterogeneous than those of differentiated lines examined and were generally greater. Although pluripotent cells had high DNA repair capacities for nucleotide excision repair, we show that ultraviolet radiation at low fluxes induced an apoptotic response in these cells, while differentiated cells lacked response to this stimulus, and note that pluripotent cells had a similar apoptotic response to alkylating agent damage. This sensitivity of pluripotent cells to damage is notable since viable pluripotent cells exhibit less ultraviolet light-induced DNA damage than do differentiated cells that receive the same flux. In addition, the importance of screening pluripotent cells for DNA repair defects was highlighted by an iPSC line that demonstrated a normal spectral karyotype, but showed both microsatellite instability and reduced DNA repair capacities in three out of four DNA repair pathways examined. Together, these results demonstrate a need to evaluate DNA repair capacities in pluripotent cell lines, in order to characterize their genomic stability, prior to their pre-clinical and clinical use. PMID:22412831

  12. QUANTITATION OF DNA TOPOISOMERASE-II-ALPHA MESSENGER-RIBONUCLEIC-ACID LEVELS IN A SMALL-CELL LUNG-CANCER CELL-LINE AND 2 DRUG-RESISTANT SUBLINES USING A POLYMERASE CHAIN REACTION-AIDED TRANSCRIPT TITRATION ASSAY

    NARCIS (Netherlands)

    WITHOFF, S; SMIT, EF; MEERSMA, GJ; van den Berg, Anke; TIMMERBOSSCHA, H; KOK, K; POSTMUS, PE; MULDER, NH; DEVRIES, EGE; BUYS, CHCM

    BACKGROUND: We have modified a polymerase chain reaction (PCR)-aided transcript titration assay (1) in order to allow quantitation of low amounts of DNA topoisomerase II alpha mRNA in small RNA samples. EXPERIMENTAL DESIGN: The titration assay was used to quantitate the amount of DNA topoisomerase

  13. DNA and RNA Extraction and Quantitative Real-Time PCR-Based Assays for Biogas Biocenoses in an Interlaboratory Comparison

    Science.gov (United States)

    Lebuhn, Michael; Derenkó, Jaqueline; Rademacher, Antje; Helbig, Susanne; Munk, Bernhard; Pechtl, Alexander; Stolze, Yvonne; Prowe, Steffen; Schwarz, Wolfgang H.; Schlüter, Andreas; Liebl, Wolfgang; Klocke, Michael

    2016-01-01

    Five institutional partners participated in an interlaboratory comparison of nucleic acid extraction, RNA preservation and quantitative Real-Time PCR (qPCR) based assays for biogas biocenoses derived from different grass silage digesting laboratory and pilot scale fermenters. A kit format DNA extraction system based on physical and chemical lysis with excellent extraction efficiency yielded highly reproducible results among the partners and clearly outperformed a traditional CTAB/chloroform/isoamylalcohol based method. Analytical purpose, sample texture, consistency and upstream pretreatment steps determine the modifications that should be applied to achieve maximum efficiency in the trade-off between extract purity and nucleic acid recovery rate. RNA extraction was much more variable, and the destination of the extract determines the method to be used. RNA stabilization with quaternary ammonium salts was an as satisfactory approach as flash freezing in liquid N2. Due to co-eluted impurities, spectrophotometry proved to be of limited value for nucleic acid qualification and quantification in extracts obtained with the kit, and picoGreen® based quantification was more trustworthy. Absorbance at 230 nm can be extremely high in the presence of certain chaotropic guanidine salts, but guanidinium isothiocyanate does not affect (q)PCR. Absolute quantification by qPCR requires application of a reliable internal standard for which correct PCR efficiency and Y-intercept values are important and must be reported. PMID:28952569

  14. [Effect of cadmium on TET enzymes and DNA methylation changes in human embryonic kidney cell].

    Science.gov (United States)

    Li, Jinhui; Li, Wenxue; Yin, Hua; Zhang, Bo; Zhu, Wei

    2015-09-01

    To detect the expression changes of the demethylase TETs (Ten-eleven translocation enzymes) in human embryonic kidney cell (HEK293) exposed to high dose cadmium chloride (CdCl2), and to investigate the regulation effects of TETs on global genomic methylation. HEK293 cells were exposed to CdCl2 for 24 h, 48 h and 72 h, the survival rate was tested by CCK-8 (cell counting kit-8) method, and the cell morphology was observed. The levels of TETs mRNA and protein were detected by fluorescence quantitative PCR and Western blot, respectively. The genomic DNA methylation level was detectedby pyro sequencing assay. CdCl2 had toxic effects on HEK293 cells, and the half inhibitory concentration (IC50) was 1.78 µmol/L. After exposure of CdCl2 for 24 h, 48 h and 72 h, the morphology of HEK293 cells was altered, and the high dose group (2.0 µmol/L) showed vacuolar changes and fuzzy appearance. The level of TET1 mRNA in groups of 0.0, 0.5, 1.0, 2.0 µmol/L were 0.23 ± 0.13, 0.48 ± 0.12, 0.59 ± 0.16 and 0.95 ± 0.39, respectively (F = 182.89, P = 0.002); The level of TET2 mRNA in groups of 0.0, 0.5, 1.0, 2.0 µmol/L were 0.23 ± 0.12, 0.32 ± 0.02,0.31 ± 0.10 and 0.34 ± 0.07, respectively (F = 27.94, P trend as mRNA levels. In 24 h (55.01 ± 3.62)%, 48 h (48.31 ± 8.99)%, 72 h (48.76 ± 6.60)%, the DNA methylation had significant differences (F = 18.50, P trend of increase according to the exposure time and dose, and the methylation level of whole genomic DNA was also altered. The demethylase TETs may play a role in regulating the genomic methylation level of HEK293 exposed to cadmium.

  15. Quantitation of J chain in human biological fluids by a simple immunochemical procedure.

    Science.gov (United States)

    Grubb, A O

    1978-01-01

    The molecular form and immunochemical properties of the J chain populations released on reduction and carboxymethylation of normal human plasma, milk, saliva and of plasma containing IgA or IgM M-components were investigated. A procedure was devised to release the entire J chain population from these various sources and to produce immunochemically identical J chain populations containing only J chain monomers. An identical standard J chain population was purified and quantitated by physiochemical means. A specific rabbit anti-J chain antiserum was raised against this pure J chain population. A simple and rapid immunochemical method for J chain quantitation in complex biological fluids as well as in solutions of pure polymeric immunoglobulins was constructed on these grounds. The J chain concentration was found to be (mean +/- S.D.) 1.74 +/- 0.65 micron in normal human plasma, 1.94 +/- 1.21 micron in human milk and 0.48 +/- 0.26 micron in human saliva. The J chain/IgA molar ratio was found to be (mean +/- S.D.) 0.45 +/- 0.07 in human milk and 0.52 +/- 0.09 in human saliva when the IgA concentration was expressed as monomeric units per volume unit. The range of the J chain/IgA molar ratios in plasma samples with highly concentrated IgA M-components was 0-0.64. The J chain/IgM molar ratio in plasma samples with highly concentrated IgM M-components was between 1 and 2 when the IgM concentration was expressed as pentameric units per volume unit.

  16. DHX9 helicase is involved in preventing genomic instability induced by alternatively structured DNA in human cells

    Science.gov (United States)

    Jain, Aklank; Bacolla, Albino; del Mundo, Imee M.; Zhao, Junhua; Wang, Guliang; Vasquez, Karen M.

    2013-01-01

    Sequences that have the capacity to adopt alternative (i.e. non-B) DNA structures in the human genome have been implicated in stimulating genomic instability. Previously, we found that a naturally occurring intra-molecular triplex (H-DNA) caused genetic instability in mammals largely in the form of DNA double-strand breaks. Thus, it is of interest to determine the mechanism(s) involved in processing H-DNA. Recently, we demonstrated that human DHX9 helicase preferentially unwinds inter-molecular triplex DNA in vitro. Herein, we used a mutation-reporter system containing H-DNA to examine the relevance of DHX9 activity on naturally occurring H-DNA structures in human cells. We found that H-DNA significantly increased mutagenesis in small-interfering siRNA-treated, DHX9-depleted cells, affecting mostly deletions. Moreover, DHX9 associated with H-DNA in the context of supercoiled plasmids. To further investigate the role of DHX9 in the recognition/processing of H-DNA, we performed binding assays in vitro and chromatin immunoprecipitation assays in U2OS cells. DHX9 recognized H-DNA, as evidenced by its binding to the H-DNA structure and enrichment at the H-DNA region compared with a control region in human cells. These composite data implicate DHX9 in processing H-DNA structures in vivo and support its role in the overall maintenance of genomic stability at sites of alternatively structured DNA. PMID:24049074

  17. Multiple reaction monitoring-based, multiplexed, absolute quantitation of 45 proteins in human plasma.

    Science.gov (United States)

    Kuzyk, Michael A; Smith, Derek; Yang, Juncong; Cross, Tyra J; Jackson, Angela M; Hardie, Darryl B; Anderson, N Leigh; Borchers, Christoph H

    2009-08-01

    Mass spectrometry-based multiple reaction monitoring (MRM) quantitation of proteins can dramatically impact the discovery and quantitation of biomarkers via rapid, targeted, multiplexed protein expression profiling of clinical samples. A mixture of 45 peptide standards, easily adaptable to common plasma proteomics work flows, was created to permit absolute quantitation of 45 endogenous proteins in human plasma trypsin digests. All experiments were performed on simple tryptic digests of human EDTA-plasma without prior affinity depletion or enrichment. Stable isotope-labeled standard peptides were added immediately following tryptic digestion because addition of stable isotope-labeled standard peptides prior to trypsin digestion was found to generate elevated and unpredictable results. Proteotypic tryptic peptides containing isotopically coded amino acids ([(13)C(6)]Arg or [(13)C(6)]Lys) were synthesized for all 45 proteins. Peptide purity was assessed by capillary zone electrophoresis, and the peptide quantity was determined by amino acid analysis. For maximum sensitivity and specificity, instrumental parameters were empirically determined to generate the most abundant precursor ions and y ion fragments. Concentrations of individual peptide standards in the mixture were optimized to approximate endogenous concentrations of analytes and to ensure the maximum linear dynamic range of the MRM assays. Excellent linear responses (r > 0.99) were obtained for 43 of the 45 proteins with attomole level limits of quantitation (proteins. Analytical precision for 44 of the 45 assays varied by proteins are within a factor of 2 of reported literature values. This mixture of internal standards has many uses and can be applied to the characterization of trypsin digestion kinetics and plasma protein expression profiling because 31 of the 45 proteins are putative biomarkers of cardiovascular disease.

  18. Replication of alpha-satellite DNA arrays in endogenous human centromeric regions and in human artificial chromosome.

    Science.gov (United States)

    Erliandri, Indri; Fu, Haiqing; Nakano, Megumi; Kim, Jung-Hyun; Miga, Karen H; Liskovykh, Mikhail; Earnshaw, William C; Masumoto, Hiroshi; Kouprina, Natalay; Aladjem, Mirit I; Larionov, Vladimir

    2014-10-01

    In human chromosomes, centromeric regions comprise megabase-size arrays of 171 bp alpha-satellite DNA monomers. The large distances spanned by these arrays preclude their replication from external sites and imply that the repetitive monomers contain replication origins. However, replication within these arrays has not previously been profiled and the role of alpha-satellite DNA in initiation of DNA replication has not yet been demonstrated. Here, replication of alpha-satellite DNA in endogenous human centromeric regions and in de novo formed Human Artificial Chromosome (HAC) was analyzed. We showed that alpha-satellite monomers could function as origins of DNA replication and that replication of alphoid arrays organized into centrochromatin occurred earlier than those organized into heterochromatin. The distribution of inter-origin distances within centromeric alphoid arrays was comparable to the distribution of inter-origin distances on randomly selected non-centromeric chromosomal regions. Depletion of CENP-B, a kinetochore protein that binds directly to a 17 bp CENP-B box motif common to alpha-satellite DNA, resulted in enrichment of alpha-satellite sequences for proteins of the ORC complex, suggesting that CENP-B may have a role in regulating the replication of centromeric regions. Mapping of replication initiation sites in the HAC revealed that replication preferentially initiated in transcriptionally active regions. Published by Oxford University Press on behalf of Nucleic Acids Research 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

  19. Validation of human papillomavirus genotyping by signature DNA sequence analysis.

    Science.gov (United States)

    Lee, Sin Hang; Vigliotti, Veronica S; Vigliotti, Jessica S; Pappu, Suri

    2009-05-22

    Screening with combined cytologic and HPV testing has led to the highest number of excessive colposcopic referrals due to high false positive rates of the current HPV testing in the USA. How best to capitalize on the enhanced sensitivity of HPV DNA testing while minimizing false-positive results from its lower specificity is an important task for the clinical pathologists. The HPV L1 gene DNA in liquid-based Pap cytology specimens was initially amplified by the degenerate MY09/MY11 PCR primers and then re-amplified by the nested GP5+/GP6+ primers, or the heminested GP6/MY11, heminested GP5/MY09 primers or their modified equivalent without sample purification or DNA extraction. The nested PCR products were used for direct automated DNA sequencing. A 34- to 50-base sequence including the GP5+ priming site was selected as the signature sequence for routine genotyping by online BLAST sequence alignment algorithms. Of 3,222 specimens, 352 were found to contain HPV DNA, with 92% of the positive samples infected by only 1 of the 35 HPV genotypes detected and 8% by more than 1 HPV genotype. The most common genotype was HPV-16 (68 isolates), followed by HPV-52 (25 isolates). More than half (53.7%) of the total number of HPV isolates relied on a nested PCR for detection although the majority of HPV-16, -18, -31, -33 -35 and -58 isolates were detected by a single MY09/MY11 PCR. Alignment of a 34-base sequence downstream of the GP5+ site failed to distinguish some isolates of HPV-16, -31 and -33. Novel variants of HPV with less than "100% identities" signature sequence match with those stored in the Genbank database were also detected by signature DNA sequencing in this rural and suburban population of the United States. Laboratory staff must be familiar with the limitations of the consensus PCR primers, the locations of the signature sequence in the L1 gene for some HPV genotypes, and HPV genotype sequence variants in order to perform accurate HPV genotyping.

  20. Validation of human papillomavirus genotyping by signature DNA sequence analysis

    Directory of Open Access Journals (Sweden)

    Vigliotti Jessica S

    2009-05-01

    Full Text Available Abstract Background Screening with combined cytologic and HPV testing has led to the highest number of excessive colposcopic referrals due to high false positive rates of the current HPV testing in the USA. How best to capitalize on the enhanced sensitivity of HPV DNA testing while minimizing false-positive results from its lower specificity is an important task for the clinical pathologists. Methods The HPV L1 gene DNA in liquid-based Pap cytology specimens was initially amplified by the degenerate MY09/MY11 PCR primers and then re-amplified by the nested GP5+/GP6+ primers, or the heminested GP6/MY11, heminested GP5/MY09 primers or their modified equivalent without sample purification or DNA extraction. The nested PCR products were used for direct automated DNA sequencing. A 34- to 50-base sequence including the GP5+ priming site was selected as the signature sequence for routine genotyping by online BLAST sequence alignment algorithms. Results Of 3,222 specimens, 352 were found to contain HPV DNA, with 92% of the positive samples infected by only 1 of the 35 HPV genotypes detected and 8% by more than 1 HPV genotype. The most common genotype was HPV-16 (68 isolates, followed by HPV-52 (25 isolates. More than half (53.7% of the total number of HPV isolates relied on a nested PCR for detection although the majority of HPV-16, -18, -31, -33 -35 and -58 isolates were detected by a single MY09/MY11 PCR. Alignment of a 34-base sequence downstream of the GP5+ site failed to distinguish some isolates of HPV-16, -31 and -33. Novel variants of HPV with less than "100% identities" signature sequence match with those stored in the Genbank database were also detected by signature DNA sequencing in this rural and suburban population of the United States. Conclusion Laboratory staff must be familiar with the limitations of the consensus PCR primers, the locations of the signature sequence in the L1 gene for some HPV genotypes, and HPV genotype sequence

  1. Evaluation of methods for the extraction and purification of DNA from the human microbiome.

    Directory of Open Access Journals (Sweden)

    Sanqing Yuan

    Full Text Available DNA extraction is an essential step in all cultivation-independent approaches to characterize microbial diversity, including that associated with the human body. A fundamental challenge in using these approaches has been to isolate DNA that is representative of the microbial community sampled.In this study, we statistically evaluated six commonly used DNA extraction procedures using eleven human-associated bacterial species and a mock community that contained equal numbers of those eleven species. These methods were compared on the basis of DNA yield, DNA shearing, reproducibility, and most importantly representation of microbial diversity. The analysis of 16S rRNA gene sequences from a mock community showed that the observed species abundances were significantly different from the expected species abundances for all six DNA extraction methods used.Protocols that included bead beating and/or mutanolysin produced significantly better bacterial community structure representation than methods without both of them. The reproducibility of all six methods was similar, and results from different experimenters and different times were in good agreement. Based on the evaluations done it appears that DNA extraction procedures for bacterial community analysis of human associated samples should include bead beating and/or mutanolysin to effectively lyse cells.

  2. A Quantitative Index to Support Recurrence Prevention Plans of Human-Related Events

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yochan; Park, Jinkyun; Jung, Wondea [KAERI, Daejeon (Korea, Republic of); Kim, Do Sam; Lee, Durk Hun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-05-15

    In Korea, HuRAM+ (Human related event Root cause Analysis Method plus) was developed to scrutinize the causes of the human-related events. The information of the human-related events investigated by the HuRAM+ method has been also managed by a database management system, R-tracer. It is obvious that accumulating data of human error causes aims to support plans that reduce recurrences of similar events. However, in spite of the efforts for the development of the human error database, it was indicated that the database does not provide useful empirical basis for establishment of the recurrence prevention plans, because the framework to interpret the collected data and apply the insights from the data into the prevention plants has not been developed yet. In this paper, in order to support establishment of the recurrence prevention plans, a quantitative index, Human Error Repeat Interval (HERI), was proposed and its applications to human error prevention were introduced. In this paper, a quantitative index, the HERI was proposed and the statistics of HERIs were introduced. These estimations can be employed to evaluate effects of recurrence prevention plans to human errors. If a mean HERI score is low and the linear trend is not positive, it can be suspected that the recurrence prevention plans applied every human-related event has not been effectively propagated. For reducing repetitive error causes, the system design or operational culture can be reviewed. If there is a strong and negative trend, systematic investigation of the root causes behind these trends is required. Likewise, we expect that the HERI index will provide significant basis for establishing or adjusting prevention plans of human errors. The accurate estimation and application of HERI scores is expected to be done after accumulating more data. When a scatter plot of HERIs is fitted by two or more models, a statistical model selection method can be employed. Some criteria have been introduced by

  3. Human in vitro skin organ culture as a model system for evaluating DNA repair.

    Science.gov (United States)

    Liu, Hannah; Tuchinda, Papapit; Fishelevich, Rita; Harberts, Erin; Gaspari, Anthony A

    2014-06-01

    UV-exposures result in accumulation of genetic lesions that facilitate the development of skin cancer. Numerous pharmacologic agents are currently under development to both inhibit formation of DNA lesions and enhance repair. Drugs must be evaluated in vitro, currently performed in cell culture systems, before being tested on humans. Current systems do not account for the architecture and diverse cellularity of intact human skin. To establish a novel, functionally viable, and reproducible in vitro skin organ culture system for studying the effects of various pharmacologic agents on DNA repair. Human skin was obtained from neonatal foreskins. Intact skin punches derived from fore