Clinical implications of cytosine deletion of exon 5 of P53 gene in non small cell lung cancer patients

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Rashid Mir

2016-01-01

Full Text Available Aim: Lung cancer is considered to be the most common cancer in the world. In humans, about 50% or more cancers have a mutated tumor suppressor p53 gene thereby resulting in accumulation of p53 protein and losing its function to activate the target genes that regulate the cell cycle and apoptosis. Extensive research conducted in murine cancer models with activated p53, loss of p53, or p53 missense mutations have facilitated researchers to understand the role of this key protein. Our study was aimed to evaluate the frequency of cytosine deletion in nonsmall cell lung cancer (NSCLC patients. Methods: One hundred NSCLC patients were genotyped for P53 (exon5, codon168 cytosine deletion leading to loss of its function and activate the target genes by allele-specific polymerase chain reaction. The P53 cytosine deletion was correlated with all the clinicopathological parameters of the patients. Results and Analysis: 59% cases were carrying P53 cytosine deletion. Similarly, the significantly higher incidence of cytosine deletion was reported in current smokers (75% in comparison to exsmoker and nonsmoker. Significantly higher frequency of cytosine deletion was reported in adenocarcinoma (68.08% than squamous cell carcinoma (52.83%. Also, a significant difference was reported between p53 cytosine deletion and metastasis (64.28%. Further, the majority of the cases assessed for response carrying P53 cytosine deletion were found to show faster disease progression. Conclusion: The data suggests that there is a significant association of the P53 exon 5 deletion of cytosine in codon 168 with metastasis and staging of the disease.

A Ser29Leu substitution in the cytosine deaminase Fca1p is responsible for clade-specific flucytosine resistance in Candida dubliniensis.

LENUS (Irish Health Repository)

McManus, Brenda A

2009-11-01

The population structure of the opportunistic yeast pathogen Candida dubliniensis is composed of three main multilocus sequence typing clades (clades C1 to C3), and clade C3 predominantly consists of isolates from the Middle East that exhibit high-level resistance (MIC(50) > or = 128 microg\\/ml) to the fungicidal agent flucytosine (5FC). The close relative of C. dubliniensis, C. albicans, also exhibits clade-specific resistance to 5FC, and resistance is most commonly mediated by an Arg101Cys substitution in the FUR1 gene encoding uracil phosphoribosyltransferase. Broth microdilution assays with fluorouracil (5FU), the toxic deaminated form of 5FC, showed that both 5FC-resistant and 5FC-susceptible C. dubliniensis isolates exhibited similar 5FU MICs, suggesting that the C. dubliniensis cytosine deaminase (Fca1p) encoded by C. dubliniensis FCA1 (CdFCA1) may play a role in mediating C. dubliniensis clade-specific 5FC resistance. Amino acid sequence analysis of the CdFCA1 open reading frame (ORF) identified a homozygous Ser29Leu substitution in all 12 5FC-resistant isolates investigated which was not present in any of the 9 5FC-susceptible isolates examined. The tetracycline-inducible expression of the CdFCA1 ORF from a 5FC-susceptible C. dubliniensis isolate in two separate 5FC-resistant clade C3 isolates restored susceptibility to 5FC, demonstrating that the Ser29Leu substitution was responsible for the clade-specific 5FC resistance and that the 5FC resistance encoded by FCA1 genes with the Ser29Leu transition is recessive. Quantitative real-time PCR analysis showed no significant difference in CdFCA1 expression between 5FC-susceptible and 5FC-resistant isolates in either the presence or the absence of subinhibitory concentrations of 5FC, suggesting that the Ser29Leu substitution in the CdFCA1 ORF is the sole cause of 5FC resistance in clade C3 C. dubliniensis isolates.

An Insight into the Environmental Effects of the Pocket of the Active Site of the Enzyme. Ab initio ONIOM-Molecular Dynamics (MD) Study on Cytosine Deaminase

International Nuclear Information System (INIS)

Matsubara, Toshiaki; Dupuis, Michel; Aida, Misako

2008-01-01

We applied the ONIOM-molecular dynamics (MD) method to cytosine deaminase to examine the environmental effects of the amino acid residues in the pocket of the active site on the substrate taking account of their thermal motion. The ab initio ONIOM-MD simulations show that the substrate uracil is strongly perturbed by the amino acid residue Ile33, which sandwiches the uracil with His62, through the steric contact due to the thermal motion. As a result, the magnitude of the thermal oscillation of the potential energy and structure of the substrate uracil significantly increases. TM and MA were partly supported by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan.MD was supported by the Division of Chemical Sciences, Office of Basic Energy Sciences, and by the Office of Biological and Environmental Research of the U.S. Department of Energy DOE. Battelle operates Pacific Northwest National Laboratory for DOE

Identification and characterization of the cytosine-5 DNA methyltransferase gene family in Salvia miltiorrhiza

OpenAIRE

Jiang Li; Caili Li; Shanfa Lu

2018-01-01

Cytosine DNA methylation is highly conserved epigenetic modification involved in a wide range of biological processes in eukaryotes. It was established and maintained by cytosine-5 DNA methyltransferases (C5-MTases) in plants. Through genome-wide identification, eight putative SmC5-MTase genes were identified from the genome of Salvia miltiorrhiza, a well-known traditional Chinese medicine material and an emerging model medicinal plant. Based on conserved domains and phylogenetic analysis, ei...

Discovery of a Bacterial 5-Methylcytosine Deaminase

Science.gov (United States)

2015-01-01

5-Methylcytosine is found in all domains of life, but the bacterial cytosine deaminase from Escherichia coli (CodA) will not accept 5-methylcytosine as a substrate. Since significant amounts of 5-methylcytosine are produced in both prokaryotes and eukaryotes, this compound must eventually be catabolized and the fragments recycled by enzymes that have yet to be identified. We therefore initiated a comprehensive phylogenetic screen for enzymes that may be capable of deaminating 5-methylcytosine to thymine. From a systematic analysis of sequence homologues of CodA from thousands of bacterial species, we identified putative cytosine deaminases where a “discriminating” residue in the active site, corresponding to Asp-314 in CodA from E. coli, was no longer conserved. Representative examples from Klebsiella pneumoniae (locus tag: Kpn00632), Rhodobacter sphaeroides (locus tag: Rsp0341), and Corynebacterium glutamicum (locus tag: NCgl0075) were demonstrated to efficiently deaminate 5-methylcytosine to thymine with values of kcat/Km of 1.4 × 105, 2.9 × 104, and 1.1 × 103 M–1 s–1, respectively. These three enzymes also catalyze the deamination of 5-fluorocytosine to 5-fluorouracil with values of kcat/Km of 1.2 × 105, 6.8 × 104, and 2.0 × 102 M–1 s–1, respectively. The three-dimensional structure of Kpn00632 was determined by X-ray diffraction methods with 5-methylcytosine (PDB id: 4R85), 5-fluorocytosine (PDB id: 4R88), and phosphonocytosine (PDB id: 4R7W) bound in the active site. When thymine auxotrophs of E. coli express these enzymes, they are capable of growth in media lacking thymine when supplemented with 5-methylcytosine. Expression of these enzymes in E. coli is toxic in the presence of 5-fluorocytosine, due to the efficient transformation to 5-fluorouracil. PMID:25384249

Regulation of Expression of the prb-1b / ACC Deaminase gene by UV-B in Transgenic tomatoes

International Nuclear Information System (INIS)

Tamot, B.K.; Pauls, K.P.; Glick, R.

2003-01-01

Transgenic tomato plants with 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase gene from Enterobacter cloacae UWA4 under the control of a pathogenesis-related promoter (prb-1b) from tobacco were challenged by abiotic stresses to determine the expression patterns of the transgene. No ACC deaminase RNA or protein was detected bu RT-PCR and in western blots prepared from leaf proteins of transgenic plants after wounding or treatment with alpha-amino butyric acid, xylanase, ethephon, salicylic acid, jasmonic acid , ethylene, or ethylene plus jasmonic acid. However, expression of the ACC deaminase transgene was observed in leaves and roots of transformed tomato lines exposed to UV light. The UV response required a minimum of 48 h of exposure and was specific to UV-B light

Discovery and structure determination of the orphan enzyme isoxanthopterin deaminase .

Science.gov (United States)

Hall, Richard S; Agarwal, Rakhi; Hitchcock, Daniel; Sauder, J Michael; Burley, Stephen K; Swaminathan, Subramanyam; Raushel, Frank M

2010-05-25

Two previously uncharacterized proteins have been identified that efficiently catalyze the deamination of isoxanthopterin and pterin 6-carboxylate. The genes encoding these two enzymes, NYSGXRC-9339a ( gi|44585104 ) and NYSGXRC-9236b ( gi|44611670 ), were first identified from DNA isolated from the Sargasso Sea as part of the Global Ocean Sampling Project. The genes were synthesized, and the proteins were subsequently expressed and purified. The X-ray structure of Sgx9339a was determined at 2.7 A resolution (Protein Data Bank entry 2PAJ ). This protein folds as a distorted (beta/alpha)(8) barrel and contains a single zinc ion in the active site. These enzymes are members of the amidohydrolase superfamily and belong to cog0402 within the clusters of orthologous groups (COG). Enzymes in cog0402 have previously been shown to catalyze the deamination of guanine, cytosine, S-adenosylhomocysteine, and 8-oxoguanine. A small compound library of pteridines, purines, and pyrimidines was used to probe catalytic activity. The only substrates identified in this search were isoxanthopterin and pterin 6-carboxylate. The kinetic constants for the deamination of isoxanthopterin with Sgx9339a were determined to be 1.0 s(-1), 8.0 muM, and 1.3 x 10(5) M(-1) s(-1) (k(cat), K(m), and k(cat)/K(m), respectively). The active site of Sgx9339a most closely resembles the active site for 8-oxoguanine deaminase (Protein Data Bank entry 2UZ9 ). A model for substrate recognition of isoxanthopterin by Sgx9339a was proposed on the basis of the binding of guanine and xanthine in the active site of guanine deaminase. Residues critical for substrate binding appear to be conserved glutamine and tyrosine residues that form hydrogen bonds with the carbonyl oxygen at C4, a conserved threonine residue that forms hydrogen bonds with N5, and another conserved threonine residue that forms hydrogen bonds with the carbonyl group at C7. These conserved active site residues were used to identify 24 other genes

Differential evolution of antiretroviral restriction factors in pteropid bats as revealed by APOBEC3 gene complexity.

Science.gov (United States)

Hayward, Joshua A; Tachedjian, Mary; Cui, Jie; Cheng, Adam Z; Johnson, Adam; Baker, Michelle; Harris, Reuben S; Wang, Lin-Fa; Tachedjian, Gilda

2018-03-29

Bats have attracted attention in recent years as important reservoirs of viruses deadly to humans and other mammals. These infections are typically nonpathogenic in bats raising questions about innate immune differences that might exist between bats and other mammals. The APOBEC3 gene family encodes antiviral DNA cytosine deaminases with important roles in the suppression of diverse viruses and genomic parasites. Here we characterize pteropid APOBEC3 genes and show that species within the genus Pteropus possess the largest and most diverse array of APOBEC3 genes identified in any mammal reported to date. Several bat APOBEC3 proteins are antiviral as demonstrated by restriction of retroviral infectivity using HIV-1 as a model, and recombinant A3Z1 subtypes possess strong DNA deaminase activity. These genes represent the first group of antiviral restriction factors identified in bats with extensive diversification relative to homologues in other mammals.

Cytosine methylation at CpCpG sites triggers accumulation of non-CpG methylation in gene bodies

OpenAIRE

Zabet, NR; Catoni, Marco; Prischi, F; Paszkowski, Jerzy Waclaw

2017-01-01

Methylation of cytosine is an epigenetic mark involved in the regulation of transcription, usually associated with transcriptional repression. In mammals, methylated cytosines are found predominantly in CpGs but in plants non-CpG methylation (in the CpHpG or CpHpH contexts, where H is A, C or T) is also present and is associated with the transcriptional silencing of transposable elements. In addition, CpG methylation is found in coding regions of active genes. In the absence of the demethylas...

Primary adenosine monophosphate (AMP) deaminase deficiency in a hypotonic infant.

Science.gov (United States)

Castro-Gago, Manuel; Gómez-Lado, Carmen; Pérez-Gay, Laura; Eirís-Puñal, Jesús; Martínez, Elena Pintos; García-Consuegra, Inés; Martín, Miguel Angel

2011-06-01

The spectrum of the adenosine monophosphate (AMP) deaminase deficiency ranges from asymptomatic carriers to patients who manifest exercise-induced muscle pain, occasionally rhabdomyolysis, and idiopathic hyperCKemia. However, previous to the introduction of molecular techniques, rare cases with congenital weakness and hypotonia have also been reported. We report a 6-month-old girl with the association of congenital muscle weakness and hypotonia, muscle deficiency of adenosine monophosphate deaminase, and the homozygous C to T mutation at nucleotide 34 of the adenosine monophosphate deaminase-1 gene. This observation indicates the possible existence of a primary adenosine monophosphate deaminase deficiency manifested by congenital muscle weakness and hypotonia.

Discovery and Structure Determination of the Orphan Enzyme Isoxanthopterin Deaminase

Energy Technology Data Exchange (ETDEWEB)

Hall, R.S.; Swaminathan, S.; Agarwal, R.; Hitchcock, D.; Sauder, J. M.; Burley, S. K.; Raushel, F. M.

2010-05-25

Two previously uncharacterized proteins have been identified that efficiently catalyze the deamination of isoxanthopterin and pterin 6-carboxylate. The genes encoding these two enzymes, NYSGXRC-9339a (gi|44585104) and NYSGXRC-9236b (gi|44611670), were first identified from DNA isolated from the Sargasso Sea as part of the Global Ocean Sampling Project. The genes were synthesized, and the proteins were subsequently expressed and purified. The X-ray structure of Sgx9339a was determined at 2.7 {angstrom} resolution (Protein Data Bank entry 2PAJ). This protein folds as a distorted ({beta}/{alpha}){sub 8} barrel and contains a single zinc ion in the active site. These enzymes are members of the amidohydrolase superfamily and belong to cog0402 within the clusters of orthologous groups (COG). Enzymes in cog0402 have previously been shown to catalyze the deamination of guanine, cytosine, S-adenosylhomocysteine, and 8-oxoguanine. A small compound library of pteridines, purines, and pyrimidines was used to probe catalytic activity. The only substrates identified in this search were isoxanthopterin and pterin 6-carboxylate. The kinetic constants for the deamination of isoxanthopterin with Sgx9339a were determined to be 1.0 s{sup -1}, 8.0 {micro}M, and 1.3 x 10{sup 5} M{sup -1} s{sup -1} (k{sub cat}, K{sub m}, and k{sub cat}/K{sub m}, respectively). The active site of Sgx9339a most closely resembles the active site for 8-oxoguanine deaminase (Protein Data Bank entry 2UZ9). A model for substrate recognition of isoxanthopterin by Sgx9339a was proposed on the basis of the binding of guanine and xanthine in the active site of guanine deaminase. Residues critical for substrate binding appear to be conserved glutamine and tyrosine residues that form hydrogen bonds with the carbonyl oxygen at C4, a conserved threonine residue that forms hydrogen bonds with N5, and another conserved threonine residue that forms hydrogen bonds with the carbonyl group at C7. These conserved active site

Tumor targeted gene therapy

International Nuclear Information System (INIS)

Kang, Joo Hyun

2006-01-01

Knowledge of molecular mechanisms governing malignant transformation brings new opportunities for therapeutic intervention against cancer using novel approaches. One of them is gene therapy based on the transfer of genetic material to an organism with the aim of correcting a disease. The application of gene therapy to the cancer treatment had led to the development of new experimental approaches such as suicidal gene therapy, inhibition of oncogenes and restoration of tumor-suppressor genes. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a prodrug into a toxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1-tk) and cytosine deaminase (CD). Especially, physicians and scientists of nuclear medicine field take an interest in suicidal gene therapy because they can monitor the location and magnitude, and duration of expression of HSV1-tk and CD by PET scanner

Evaluation of the adenosine deaminase (ADA) G22A gene polymorphism with recurrent spontaneous abortion among Egyptian patients

Science.gov (United States)

Abu-Gabal, Khadiga; Katta, Maha; Ibrahim, Raghda

2017-01-01

Introduction Adenosine and deoxyadenosine metabolism is influenced by adenosine deaminase (ADA) enzyme. ADA increases in different diseases and is considered as one of the markers for cell-mediated immunity. Pregnancy is associated with depressed cell-mediated immunity. The level of ADA expression, which seems to play a key role in maintaining pregnancy, is influenced by adenosine deaminase G22A gene polymorphism. We aimed in our study to evaluate the association of ADA G22A gene polymorphism with recurrent spontaneous abortion (RSA) in Egyptian women. Material and methods Adenosine deaminase G22A gene polymorphism was genotyped in 40 patients (age range 22-39 years) with a history of RSA, selected from those attending the Gynaecology and Obstetrics Clinic of Beni-Suef University Hospital, and 20 age-matched healthy women as a control group, using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. Results In our study, no statistically significant difference was found between RSA patients and control group as regards ADA G22A genotypes (p = 0.653) and alleles (p = 0.697). A comparison of the frequencies of ADA alleles in RSA patients as regards the below-35-years-old age group revealed that ADA 2(A) allele was associated with a low risk for RSA in patients aged 35 years old or younger (p = 0.008). Conclusions In conclusion, our study revealed an age-dependent protective value of ADA 2(A) allele in recurrent spontaneous abortions among the Egyptian population. PMID:29204093

Targeting a Novel Vector for Breast Cancer Gene Therapy

National Research Council Canada - National Science Library

Bzik, David

2002-01-01

... in vitro and in vivo models. We found that cytosine deaminase (CD) and thymidine kinase (TK) markers expressed in T gondii produce a significant bystander killing effect on both human fibroblasts and SKBR3 tumor cells in vitro...

Dynamic DNA cytosine methylation in the Populus trichocarpa genome: tissue-level variation and relationship to gene expression

Directory of Open Access Journals (Sweden)

Vining Kelly J

2012-01-01

Full Text Available Abstract Background DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood. Results We surveyed DNA methylation from seven distinct tissue types (vegetative bud, male inflorescence [catkin], female catkin, leaf, root, xylem, phloem in the reference tree species black cottonwood (Populus trichocarpa. Using 5-methyl-cytosine DNA immunoprecipitation followed by Illumina sequencing (MeDIP-seq, we mapped a total of 129,360,151 36- or 32-mer reads to the P. trichocarpa reference genome. We validated MeDIP-seq results by bisulfite sequencing, and compared methylation and gene expression using published microarray data. Qualitative DNA methylation differences among tissues were obvious on a chromosome scale. Methylated genes had lower expression than unmethylated genes, but genes with methylation in transcribed regions ("gene body methylation" had even lower expression than genes with promoter methylation. Promoter methylation was more frequent than gene body methylation in all tissues except male catkins. Male catkins differed in demethylation of particular transposable element categories, in level of gene body methylation, and in expression range of genes with methylated transcribed regions. Tissue-specific gene expression patterns were correlated with both gene body and promoter methylation. Conclusions We found striking differences among tissues in methylation, which were apparent at the chromosomal scale and when genes and transposable elements were examined. In contrast to other studies in plants, gene body methylation had a more repressive effect on transcription than promoter methylation.

High-resolution analysis of cytosine methylation in ancient DNA.

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Bastien Llamas

Full Text Available Epigenetic changes to gene expression can result in heritable phenotypic characteristics that are not encoded in the DNA itself, but rather by biochemical modifications to the DNA or associated chromatin proteins. Interposed between genes and environment, these epigenetic modifications can be influenced by environmental factors to affect phenotype for multiple generations. This raises the possibility that epigenetic states provide a substrate for natural selection, with the potential to participate in the rapid adaptation of species to changes in environment. Any direct test of this hypothesis would require the ability to measure epigenetic states over evolutionary timescales. Here we describe the first single-base resolution of cytosine methylation patterns in an ancient mammalian genome, by bisulphite allelic sequencing of loci from late Pleistocene Bison priscus remains. Retrotransposons and the differentially methylated regions of imprinted loci displayed methylation patterns identical to those derived from fresh bovine tissue, indicating that methylation patterns are preserved in the ancient DNA. Our findings establish the biochemical stability of methylated cytosines over extensive time frames, and provide the first direct evidence that cytosine methylation patterns are retained in DNA from ancient specimens. The ability to resolve cytosine methylation in ancient DNA provides a powerful means to study the role of epigenetics in evolution.

Single nucleotide editing without DNA cleavage using CRISPR/Cas9-deaminase in the sea urchin embryo.

Science.gov (United States)

Shevidi, Saba; Uchida, Alicia; Schudrowitz, Natalie; Wessel, Gary M; Yajima, Mamiko

2017-12-01

A single base pair mutation in the genome can result in many congenital disorders in humans. The recent gene editing approach using CRISPR/Cas9 has rapidly become a powerful tool to replicate or repair such mutations in the genome. These approaches rely on cleaving DNA, while presenting unexpected risks. In this study, we demonstrate a modified CRISPR/Cas9 system fused to cytosine deaminase (Cas9-DA), which induces a single nucleotide conversion in the genome. Cas9-DA was introduced into sea urchin eggs with sgRNAs targeted for SpAlx1, SpDsh, or SpPks, each of which is critical for skeletogenesis, embryonic axis formation, or pigment formation, respectively. We found that both Cas9 and Cas9-DA edit the genome, and cause predicted phenotypic changes at a similar efficiency. Cas9, however, resulted in significant deletions in the genome centered on the gRNA target sequence, whereas Cas9-DA resulted in single or double nucleotide editing of C to T conversions within the gRNA target sequence. These results suggest that the Cas9-DA approach may be useful for manipulating gene activity with decreased risks of genomic aberrations. Developmental Dynamics 246:1036-1046, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Transcriptional similarity in couples reveals the impact of shared environment and lifestyle on gene regulation through modified cytosines

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Ke Tang

2016-06-01

Full Text Available Gene expression is a complex and quantitative trait that is influenced by both genetic and non-genetic regulators including environmental factors. Evaluating the contribution of environment to gene expression regulation and identifying which genes are more likely to be influenced by environmental factors are important for understanding human complex traits. We hypothesize that by living together as couples, there can be commonly co-regulated genes that may reflect the shared living environment (e.g., diet, indoor air pollutants, behavioral lifestyle. The lymphoblastoid cell lines (LCLs derived from unrelated couples of African ancestry (YRI, Yoruba people from Ibadan, Nigeria from the International HapMap Project provided a unique model for us to characterize gene expression pattern in couples by comparing gene expression levels between husbands and wives. Strikingly, 778 genes were found to show much smaller variances in couples than random pairs of individuals at a false discovery rate (FDR of 5%. Since genetic variation between unrelated family members in a general population is expected to be the same assuming a random-mating society, non-genetic factors (e.g., epigenetic systems are more likely to be the mediators for the observed transcriptional similarity in couples. We thus evaluated the contribution of modified cytosines to those genes showing transcriptional similarity in couples as well as the relationships these CpG sites with other gene regulatory elements, such as transcription factor binding sites (TFBS. Our findings suggested that transcriptional similarity in couples likely reflected shared common environment partially mediated through cytosine modifications.

Microhydration of cytosine and its radical anion: Cytosine.(H2O)n (n=1-5)

Science.gov (United States)

Kim, Sunghwan; Schaefer, Henry F.

2007-02-01

Microhydration effects on cytosine and its radical anion have been investigated theoretically, by explicitly considering various structures of cytosine complexes with up to five water molecules. Each successive water molecule (through n =5) is bound by 7-10kcalmol-1 to the relevant cytosine complex. The hydration energies are uniformly higher for the analogous anion systems. While the predicted vertical detachment energy (VDE) of the isolated cytosine is only 0.48eV, it is predicted to increase to 1.27eV for the lowest-lying pentahydrate of cytosine. The adiabatic electron affinity (AEA) of cytosine was also found to increase from 0.03to0.61eV for the pentahydrate, implying that the cytosine anion, while questionable in the gas phase, is bound in aqueous solution. Both the VDE and AEA values for cytosine are smaller than those of uracil and thymine for a given hydration number. These results are in qualitative agreement with available experimental results from photodetachment-photoelectron spectroscopy studies of Schiedt et al. [Chem. Phys. 239, 511 (1998)].

Pleiotropic phenotypes of the salt-tolerant and cytosine ...

Indian Academy of Sciences (India)

2SKA Institution for Research, Education and Development (SKAIRED), 4/11 Sarv Priya Vihar, ... wild-type parent cv Nirmal were characterized for overall cytosine methylation at .... (ii) altered in the expression of genes involved in the perfor-.

Bystander or No Bystander for Gene Directed Enzyme Prodrug Therapy

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Adam V. Patterson

2009-11-01

Full Text Available Gene directed enzyme prodrug therapy (GDEPT of cancer aims to improve the selectivity of chemotherapy by gene transfer, thus enabling target cells to convert nontoxic prodrugs to cytotoxic drugs. A zone of cell kill around gene-modified cells due to transfer of toxic metabolites, known as the bystander effect, leads to tumour regression. Here we discuss the implications of either striving for a strong bystander effect to overcome poor gene transfer, or avoiding the bystander effect to reduce potential systemic effects, with the aid of three successful GDEPT systems. This review concentrates on bystander effects and drug development with regard to these enzyme prodrug combinations, namely herpes simplex virus thymidine kinase (HSV-TK with ganciclovir (GCV, cytosine deaminase (CD from bacteria or yeast with 5-fluorocytodine (5-FC, and bacterial nitroreductase (NfsB with 5-(azaridin-1-yl-2,4-dinitrobenzamide (CB1954, and their respective derivatives.

Activation-induced cytidine deaminase (AID) is localized to subnuclear domains enriched in splicing factors

Energy Technology Data Exchange (ETDEWEB)

Hu, Yi, E-mail: yihooyi@gmail.com; Ericsson, Ida, E-mail: ida.ericsson@ntnu.no; Doseth, Berit, E-mail: berit.doseth@ntnu.no; Liabakk, Nina B., E-mail: nina.beate.liabakk@ntnu.no; Krokan, Hans E., E-mail: hans.krokan@ntnu.no; Kavli, Bodil, E-mail: bodil.kavli@ntnu.no

2014-03-10

Activation-induced cytidine deaminase (AID) is the mutator enzyme in adaptive immunity. AID initiates the antibody diversification processes in activated B cells by deaminating cytosine to uracil in immunoglobulin genes. To some extent other genes are also targeted, which may lead to genome instability and B cell malignancy. Thus, it is crucial to understand its targeting and regulation mechanisms. AID is regulated at several levels including subcellular compartmentalization. However, the complex nuclear distribution and trafficking of AID has not been studied in detail previously. In this work, we examined the subnuclear localization of AID and its interaction partner CTNNBL1 and found that they associate with spliceosome-associated structures including Cajal bodies and nuclear speckles. Moreover, protein kinase A (PKA), which activates AID by phosphorylation at Ser38, is present together with AID in nuclear speckles. Importantly, we demonstrate that AID physically associates with the major spliceosome subunits (small nuclear ribonucleoproteins, snRNPs), as well as other essential splicing components, in addition to the transcription machinery. Based on our findings and the literature, we suggest a transcription-coupled splicing-associated model for AID targeting and activation. - Highlights: • AID and its interaction partner CTNNBL1 localize to Cajal bodies and nuclear speckles. • AID associates with its activating kinase PKA in nuclear speckles. • AID is linked to the splicing machinery in switching B-cells. • Our findings suggest a transcription-coupled splicing associated mechanism for AID targeting and activation.

Effects of cytosine methylation on transcription factor binding sites

KAUST Repository

Medvedeva, Yulia A

2014-03-26

Background: DNA methylation in promoters is closely linked to downstream gene repression. However, whether DNA methylation is a cause or a consequence of gene repression remains an open question. If it is a cause, then DNA methylation may affect the affinity of transcription factors (TFs) for their binding sites (TFBSs). If it is a consequence, then gene repression caused by chromatin modification may be stabilized by DNA methylation. Until now, these two possibilities have been supported only by non-systematic evidence and they have not been tested on a wide range of TFs. An average promoter methylation is usually used in studies, whereas recent results suggested that methylation of individual cytosines can also be important.Results: We found that the methylation profiles of 16.6% of cytosines and the expression profiles of neighboring transcriptional start sites (TSSs) were significantly negatively correlated. We called the CpGs corresponding to such cytosines " traffic lights" We observed a strong selection against CpG " traffic lights" within TFBSs. The negative selection was stronger for transcriptional repressors as compared with transcriptional activators or multifunctional TFs as well as for core TFBS positions as compared with flanking TFBS positions.Conclusions: Our results indicate that direct and selective methylation of certain TFBS that prevents TF binding is restricted to special cases and cannot be considered as a general regulatory mechanism of transcription. 2013 Medvedeva et al.; licensee BioMed Central Ltd.

Characterization of the Escherichia coli codBA operon encoding cytosine permease and cytosine deaminase

DEFF Research Database (Denmark)

Danielsen, S; Kilstrup, M; Barilla, K

1992-01-01

. A two-codon overlap between the two reading frames indicates that they constitute an operon. Transcription of the operon was found to be regulated by exogenous purines. Polypeptides specified by each of the two reading frames were expressed in minicells, and the codB gene product was found to be highly...

Genome-wide identification and comparative analysis of cytosine-5 DNA methyltransferases and demethylase families in wild and cultivated peanut

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Pengfei eWang

2016-02-01

Full Text Available AbstractDNA methylation plays important roles in genome protection, regulation of gene expression and was associated with plants development. Plant DNA methylation pattern was mediated by cytosine-5 DNA methyltransferases and demethylase. Although the genomes of AA and BB wild peanuts have been fully sequence, these two gene families have not been studied. In this study we report the identification and analysis of putative cytosine-5 DNA methyltransferases (C5-MTases and demethylase in AA and BB wild peanuts. Cytosine-5 DNA methyltransferases in AA and BB wild peanuts could be classified in known MET, CMT and DRM2 groups based on their domain organization. This result was supported by the gene and protein structural characteristics and phylogenetic analysis. We found that some wild peanut DRM2 numbers didn’t contain UBA domain which was different from other plants such as Arabidopsis, maize, soybean. Five DNA demethylase were found in AA genome and five in BB genome. The selective pressure analysis showed that wild peanut C5-MTases gene mainly underwent purifying selection but many positive selection sites can be detected. Conversely, DNA demethylase genes mainly underwent positive selection during evolution. Additionally, the expression dynamic of cytosine-5 DNA methyltransferases and demethylase genes in different cultivated peanut tissues were analyzed. Expression result showed that cold, heat or drought stress could influence the expression level of C5-MTases and DNA demethylase genes in cultivated peanut. These results are useful for better understanding the complexity of these two gene families, and will facilitate epigenetic studies in peanut.

Cytosine deamination and the precipitous decline of spontaneous mutation during Earth's history.

Science.gov (United States)

Lewis, Charles A; Crayle, Jesse; Zhou, Shuntai; Swanstrom, Ronald; Wolfenden, Richard

2016-07-19

The hydrolytic deamination of cytosine and 5-methylcytosine residues in DNA appears to contribute significantly to the appearance of spontaneous mutations in microorganisms and in human disease. In the present work, we examined the mechanism of cytosine deamination and the response of the uncatalyzed reaction to changing temperature. The positively charged 1,3-dimethylcytosinium ion was hydrolyzed at a rate similar to the rate of acid-catalyzed hydrolysis of 1-methylcytosine, for which it furnishes a satisfactory kinetic model and a probable mechanism. In agreement with earlier reports, uncatalyzed deamination was found to proceed at very similar rates for cytosine, 1-methylcytosine, cytidine, and cytidine 5'-phosphate, and also for cytosine residues in single-stranded DNA generated from a phagemid, in which we sequenced an insert representing the gene of the HIV-1 protease. Arrhenius plots for the uncatalyzed deamination of cytosine were linear over the temperature range from 90 °C to 200 °C and indicated a heat of activation (ΔH(‡)) of 23.4 ± 0.5 kcal/mol at pH 7. Recent evidence indicates that the surface of the earth has been cool enough to support life for more than 4 billion years and that life has been present for almost as long. If the temperature at Earth's surface is assumed to have followed Newton's law of cooling, declining exponentially from 100 °C to 25 °C during that period, then half of the cytosine-deaminating events per unit biomass would have taken place during the first 0.2 billion years, and <99.4% would have occurred during the first 2 billion years.

Assignment of adenosine deaminase complexing protein (ADCP) gene(s) to human chromosome 2 in rodent-human somatic cell hybrids.

Science.gov (United States)

Herbschleb-Voogt, E; Grzeschik, K H; Pearson, P L; Meera Khan, P

1981-01-01

The experiments reported in this paper indicate that the expression of human adenosine deaminase complexing protein (ADCP) in the human-rodent somatic cell hybrids is influenced by the state of confluency of the cells and the background rodent genome. Thus, the complement of the L-cell derived A9 or B82 mouse parent apparently prevents the expression of human ADCP in the interspecific somatic cell hybrids. In the a3, E36, or RAG hybrids the human ADCP expression was not prevented by the rodent genome and was found to be proportional to the degree of confluency of the cell in the culture as in the case of primary human fibroblasts. An analysis of human chromosomes, chromosome specific enzyme markers, and ADCP in a panel of rodent-human somatic cell hybrids optimally maintained and harvested at full confluency has shown that the expression of human ADCP in the mouse (RAG)-human as well as in the hamster (E36 or a3)-human hybrids is determined by a gene(s) in human chromosome 2 and that neither chromosome 6 nor any other of the chromosomes of man carry any gene(s) involved in the formation of human ADCP at least in the Chinese hamster-human hybrids. A series of rodent-human hybrid clones exhibiting a mitotic separation of IDH1 and MDH1 indicated that ADCP is most probably situated between corresponding loci in human chromosome 2.

Gene therapy for adenosine deaminase-deficient severe combined immune deficiency: clinical comparison of retroviral vectors and treatment plans.

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Candotti, Fabio; Shaw, Kit L; Muul, Linda; Carbonaro, Denise; Sokolic, Robert; Choi, Christopher; Schurman, Shepherd H; Garabedian, Elizabeth; Kesserwan, Chimene; Jagadeesh, G Jayashree; Fu, Pei-Yu; Gschweng, Eric; Cooper, Aaron; Tisdale, John F; Weinberg, Kenneth I; Crooks, Gay M; Kapoor, Neena; Shah, Ami; Abdel-Azim, Hisham; Yu, Xiao-Jin; Smogorzewska, Monika; Wayne, Alan S; Rosenblatt, Howard M; Davis, Carla M; Hanson, Celine; Rishi, Radha G; Wang, Xiaoyan; Gjertson, David; Yang, Otto O; Balamurugan, Arumugam; Bauer, Gerhard; Ireland, Joanna A; Engel, Barbara C; Podsakoff, Gregory M; Hershfield, Michael S; Blaese, R Michael; Parkman, Robertson; Kohn, Donald B

2012-11-01

We conducted a gene therapy trial in 10 patients with adenosine deaminase (ADA)-deficient severe combined immunodeficiency using 2 slightly different retroviral vectors for the transduction of patients' bone marrow CD34(+) cells. Four subjects were treated without pretransplantation cytoreduction and remained on ADA enzyme-replacement therapy (ERT) throughout the procedure. Only transient (months), low-level (< 0.01%) gene marking was observed in PBMCs of 2 older subjects (15 and 20 years of age), whereas some gene marking of PBMC has persisted for the past 9 years in 2 younger subjects (4 and 6 years). Six additional subjects were treated using the same gene transfer protocol, but after withdrawal of ERT and administration of low-dose busulfan (65-90 mg/m(2)). Three of these remain well, off ERT (5, 4, and 3 years postprocedure), with gene marking in PBMC of 1%-10%, and ADA enzyme expression in PBMC near or in the normal range. Two subjects were restarted on ERT because of poor gene marking and immune recovery, and one had a subsequent allogeneic hematopoietic stem cell transplantation. These studies directly demonstrate the importance of providing nonmyeloablative pretransplantation conditioning to achieve therapeutic benefits with gene therapy for ADA-deficient severe combined immunodeficiency.

How We Manage Adenosine Deaminase-Deficient Severe Combined Immune Deficiency (ADA SCID).

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Kohn, Donald B; Gaspar, H Bobby

2017-05-01

Adenosine deaminase-deficient severe combined immune deficiency (ADA SCID) accounts for 10-15% of cases of human SCID. From what was once a uniformly fatal disease, the prognosis for infants with ADA SCID has improved greatly based on the development of multiple therapeutic options, coupled with more frequent early diagnosis due to implementation of newborn screening for SCID. We review the various treatment approaches for ADA SCID including allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen-matched sibling or family member or from a matched unrelated donor or a haplo-identical donor, autologous HSCT with gene correction of the hematopoietic stem cells (gene therapy-GT), and enzyme replacement therapy (ERT) with polyethylene glycol-conjugated adenosine deaminase. Based on growing evidence of safety and efficacy from GT, we propose a treatment algorithm for patients with ADA SCID that recommends HSCT from a matched family donor, when available, as a first choice, followed by GT as the next option, with allogeneic HSCT from an unrelated or haplo-identical donor or long-term ERT as other options.

Clinical efficacy of gene-modified stem cells in adenosine deaminase-deficient immunodeficiency.

Science.gov (United States)

Shaw, Kit L; Garabedian, Elizabeth; Mishra, Suparna; Barman, Provaboti; Davila, Alejandra; Carbonaro, Denise; Shupien, Sally; Silvin, Christopher; Geiger, Sabine; Nowicki, Barbara; Smogorzewska, E Monika; Brown, Berkley; Wang, Xiaoyan; de Oliveira, Satiro; Choi, Yeong; Ikeda, Alan; Terrazas, Dayna; Fu, Pei-Yu; Yu, Allen; Fernandez, Beatriz Campo; Cooper, Aaron R; Engel, Barbara; Podsakoff, Greg; Balamurugan, Arumugam; Anderson, Stacie; Muul, Linda; Jagadeesh, G Jayashree; Kapoor, Neena; Tse, John; Moore, Theodore B; Purdy, Ken; Rishi, Radha; Mohan, Kathey; Skoda-Smith, Suzanne; Buchbinder, David; Abraham, Roshini S; Scharenberg, Andrew; Yang, Otto O; Cornetta, Kenneth; Gjertson, David; Hershfield, Michael; Sokolic, Rob; Candotti, Fabio; Kohn, Donald B

2017-05-01

Autologous hematopoietic stem cell transplantation (HSCT) of gene-modified cells is an alternative to enzyme replacement therapy (ERT) and allogeneic HSCT that has shown clinical benefit for adenosine deaminase-deficient (ADA-deficient) SCID when combined with reduced intensity conditioning (RIC) and ERT cessation. Clinical safety and therapeutic efficacy were evaluated in a phase II study. Ten subjects with confirmed ADA-deficient SCID and no available matched sibling or family donor were enrolled between 2009 and 2012 and received transplantation with autologous hematopoietic CD34+ cells that were modified with the human ADA cDNA (MND-ADA) γ-retroviral vector after conditioning with busulfan (90 mg/m2) and ERT cessation. Subjects were followed from 33 to 84 months at the time of data analysis. Safety of the procedure was assessed by recording the number of adverse events. Efficacy was assessed by measuring engraftment of gene-modified hematopoietic stem/progenitor cells, ADA gene expression, and immune reconstitution. With the exception of the oldest subject (15 years old at enrollment), all subjects remained off ERT with normalized peripheral blood mononuclear cell (PBMC) ADA activity, improved lymphocyte numbers, and normal proliferative responses to mitogens. Three of nine subjects were able to discontinue intravenous immunoglobulin replacement therapy. The MND-ADA vector was persistently detected in PBMCs (vector copy number [VCN] = 0.1-2.6) and granulocytes (VCN = 0.01-0.3) through the most recent visits at the time of this writing. No patient has developed a leukoproliferative disorder or other vector-related clinical complication since transplant. These results demonstrate clinical therapeutic efficacy from gene therapy for ADA-deficient SCID, with an excellent clinical safety profile. ClinicalTrials.gov NCT00794508. Food and Drug Administration Office of Orphan Product Development award, RO1 FD003005; NHLBI awards, PO1 HL73104 and Z01 HG000122; UCLA

Myoadenylate deaminase deficiency, hypertrophic cardiomyopathy and gigantism syndrome.

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Skyllouriotis, M L; Marx, M; Bittner, R E; Skyllouriotis, P; Gross, M; Wimmer, M

1997-07-01

We report a 20-year-old man with gigantism syndrome, hypertrophic cardiomyopathy, muscle weakness, exercise intolerance, and severe psychomotor retardation since childhood. Histochemical and biochemical analysis of skeletal muscle biopsy revealed myoadenylate deaminase deficiency; molecular genetic analysis confirmed the diagnosis of primary (inherited) myoadenylate deaminase deficiency. Plasma, urine, and muscle carnitine concentrations were reduced. L-Carnitine treatment led to gradual improvement in exercise tolerance and cognitive performance; plasma and tissue carnitine levels returned to normal, and echocardiographic evidence of left ventricular hypertrophy disappeared. The combination of inherited myoadenylate deaminase deficiency, gigantism syndrome and carnitine deficiency has not previously been described.

Photochemistry of DNA containing iodinated cytosine

Energy Technology Data Exchange (ETDEWEB)

Rahn, R O; Stafford, R S [Oak Ridge National Lab., TN (USA)

1979-10-01

Irradiation at 313 nm of compounds containing iodinated cytosine moieties results in the photolysis of iodine. Photolysis occurs with a quantum yield of 0.022-0.024 for 5-iododeoxycytidine and 5-iododeoxycytidine monophosphate, and 0.004-0.008 for iodinated DNA as well as for iodinated polycytidylate. Photodegradation of the cytosine moiety occurs when air is present during irradiation, presumably due to the reaction of oxygen with the cytosyl radical formed when iodine is lost. This oxygen promoted photodegradation destroys the cytosine chromophore and is complete in the monomers but occurs to only a limited extent in the polymers. In the absence of oxygen or in the presence of ethanol, photodegradation is prevented and the loss of iodine leads exclusively to the formation of the cytosine chromophore. In DNA, the loss of iodine is accompanied by the formation of sugar damage and/or chain breaks. As measured by sedimentation in alkaline sucrose gradients, approximately one break is made for every six iodines lost in denatured DNA. The frequency of chain breakage per iodine photolyzed is reduced 2-fold in renatured DNA. Analysis in neutral gradients suggests that half of the breaks observed in alkali are alkali-labile bonds. Both ethanol and cysteamine reduce the number of chain breaks in alkali by approximately 3-fold.

Expression of activation-induced cytidine deaminase gene in B lymphocytes of patients with common variable immunodeficiency.

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Abolhassani, Hassan; Farrokhi, Amir Salek; Pourhamdi, Shabnam; Mohammadinejad, Payam; Sadeghi, Bamdad; Moazzeni, Seyed-Mohammad; Aghamohammadi, Asghar

2013-08-01

Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by reduced serum level of IgG, IgA or IgM and recurrent bacterial infections. Class switch recombination (CSR) as a critical process in immunoglobulin production is defective in a group of CVID patients. Activation-induced cytidine deaminase (AID) protein is an important molecule involving CSR process. The aim of this study was to investigate the AID gene mRNA production in a group of CVID patients indicating possible role of this molecule in this disorder. Peripheral blood mononuclear cells (PBMC) of 29 CVID patients and 21 healthy controls were isolated and stimulated by CD40L and IL-4 to induce AID gene expression. After 5 days AID gene mRNA production was investigated by real time polymerase chain reaction. AID gene was expressed in all of the studied patients. However the mean density of extracted AID mRNA showed higher level in CVID patients (230.95±103.04 ng/ml) rather than controls (210.00±44.72 ng/ml; P=0.5). CVID cases with lower level of AID had decreased total level of IgE (P=0.04) and stimulated IgE production (P=0.02); while cases with increased level of AID presented higher level of IgA (P=0.04) and numbers of B cells (P=0.02) and autoimmune disease (P=0.02). Different levels of AID gene expression may have important roles in dysregulation of immune system and final clinical presentation in CVID patients. Therefore investigating the expression of AID gene can help in classifying CVID patients.

Hydroxyl radical induced cross-linking of cytosine and tyrosine in nucleohistone

International Nuclear Information System (INIS)

Gajewski, E.; Dizdaroglu, M.

1990-01-01

Hydroxyl radical induced formation of a DNA-protein cross-link involving cytosine and tyrosine in nucleohistone in buffered aqueous solution is reported. The technique of gas chromatography-mass spectrometry was used for this investigation. A γ-irradiated aqueous mixture of cytosine and tyrosine was first investigated in order to obtain gas chromatographic-mass spectrometric properties of possible cytosine-tyrosine cross-links. One cross-link was observed, and its structure was identified as the product from the formation of a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. With the use of gas chromatography-mass spectrometry with selected-ion monitoring, this cytosine-tyrosine cross-link was identified in acidic hydrolysates of calf thymus nucleohistone γ-irradiated in N 2 O-saturated aqueous solution. The yield of this DNA-protein cross-link in nucleohistone was found to be a linear function of the radiation dose in the range of 100-500 Gy (J·kg -1 ). This yield amounted to 0.05 nmol·J -1 . Mechanisms underlying the formation of the cytosine-tyrosine cross-link in nucleohistone were proposed to involve radical-radical and/or radical addition reactions of hydroxyl adduct radicals of cytosine and tyrosine moieties, forming a covalent bond between carbon 6 of cytosine and carbon 3 of tyrosine. When oxygen was present in irradiated solutions, no cytosine-tyrosine cross-links were observed

Autosomal recessive hyper IgM syndrome associated with activation-induced cytidine deaminase gene in three Turkish siblings presented with tuberculosis lymphadenitis - Case report.

Science.gov (United States)

Patiroglu, Turkan; Akar, H Haluk; van der Burg, Mirjam; Unal, Ekrem

2015-09-01

The hyper-immunoglobulin M (HIGM) syndrome is a heterogeneous group of genetic disorders characterized by recurrent infections, decreased serum levels of immunoglobulin G (IgG) and IgA, and normal/increased serum levels of IgM. Herein, we describe three Turkish siblings with HIGM syndrome who had a homozygous missense mutation (c.70C>T, p.Arg24Trp) in the activation-induced cytidine deaminase gene which results in autosomal recessive HIGM syndrome. Two of the siblings, sibling 1 and sibling 3, presented with cervical deep abscess and cervical tuberculosis lymphadenitis, respectively.

Activation-induced cytidine deaminase induces reproducible DNA breaks at many non-Ig Loci in activated B cells

NARCIS (Netherlands)

Staszewski, Ori; Baker, Richard E.; Ucher, Anna J.; Martier, Raygene; Stavnezer, Janet; Guikema, Jeroen E. J.

2011-01-01

After immunization or infection, activation-induced cytidine deaminase (AID) initiates diversification of immunoglobulin (Ig) genes in B cells, introducing mutations within the antigen-binding V regions (somatic hypermutation, SHM) and double-strand DNA breaks (DSBs) into switch (S) regions, leading

Assays for noninvasive imaging of reporter gene expression

International Nuclear Information System (INIS)

Gambhir, S.S.; Barrio, J.R.; Herschman, H.R.; Phelps, M.E.

1999-01-01

Repeated, noninvasive imaging of reporter gene expression is emerging as a valuable tool for monitoring the expression of genes in animals and humans. Monitoring of organ/cell transplantation in living animals and humans, and the assessment of environmental, behavioral, and pharmacologic modulation of gene expression in transgenic animals should soon be possible. The earliest clinical application is likely to be monitoring human gene therapy in tumors transduced with the herpes simplex virus type 1 thymidine kinase (HSV1-tk) suicide gene. Several candidate assays for imaging reporter gene expression have been studied, utilizing cytosine deaminase (CD), HSV1-tk, and dopamine 2 receptor (D2R) as reporter genes. For the HSV1-tk reporter gene, both uracil nucleoside derivatives (e.g., 5-iodo-2'-fluoro-2'-deoxy-1-β-D-arabinofuranosyl-5-iodouracil [FIAU] labeled with 124 I, 131 I ) and acycloguanosine derivatives {e.g., 8-[ 18 F]fluoro-9-[[2-hydroxy-1-(hydroxymethyl)ethoxy]methyl]guanine (8-[ 18 F]-fluoroganciclovir) ([ 18 F]FGCV), 9-[(3-[ 18 F]fluoro-1-hydroxy-2-propoxy)methyl]guanine ([ 18 F]FHPG)} have been investigated as reporter probes. For the D2R reporter gene, a derivative of spiperone {3-(2'-[ 18 F]-Fluoroethyl)spiperone ([ 18 F]FESP)} has been used with positron emission tomography (PET) imaging. In this review, the principles and specific assays for imaging reporter gene expression are presented and discussed. Specific examples utilizing adenoviral-mediated delivery of a reporter gene as well as tumors expressing reporter genes are discussed

Markerless deletion of putative alanine dehydrogenase genes in Bacillus licheniformis using a codBA-based counterselection technique.

Science.gov (United States)

Kostner, David; Rachinger, Michael; Liebl, Wolfgang; Ehrenreich, Armin

2017-11-01

Bacillus licheniformis strains are used for the large-scale production of industrial exoenzymes from proteinaceous substrates, but details of the amino acid metabolism involved are largely unknown. In this study, two chromosomal genes putatively involved in amino acid metabolism of B. licheniformis were deleted to clarify their role. For this, a convenient counterselection system for markerless in-frame deletions was developed for B. licheniformis. A deletion plasmid containing up- and downstream DNA segments of the chromosomal deletion target was conjugated to B. licheniformis and integrated into the genome by homologous recombination. Thereafter, the counterselection was done by using a codBA cassette. The presence of cytosine deaminase and cytosine permease exerted a conditionally lethal phenotype on B. licheniformis cells in the presence of the cytosine analogue 5-fluorocytosine. Thereby clones were selected that lost the integrated vector sequence and the anticipated deletion target after a second recombination step. This method allows the construction of markerless mutants in Bacillus strains in iterative cycles. B. licheniformis MW3 derivatives lacking either one of the ORFs BL03009 or BL00190, encoding a putative alanine dehydrogenase and a similar putative enzyme, respectively, retained the ability to grow in minimal medium supplemented with alanine as the carbon source. In the double deletion mutant MW3 ΔBL03009 ΔBL00190, however, growth on alanine was completely abolished. These data indicate that the two encoded enzymes are paralogues fulfilling mutually replaceable functions in alanine utilization, and suggest that in B. licheniformis MW3 alanine utilization is initiated by direct oxidative transamination to pyruvate and ammonium.

Syntheses of [5-2H]-uracil, [5-2H]-cytosine, [6-2H]-uracil and [6-2H]-cytosine

International Nuclear Information System (INIS)

Kiritani, Reiko; Asano, Takeyoshi; Fujita, Shin-ichi; Dohmaru, Takaaki; Kawanishi, Tetsuro

1986-01-01

Syntheses of [5- 2 H]-, [6- 2 H]-uracil and [5- 2 H]-, [6- 2 H]-cytosine were investigated. The catalytic reaction of uracil or cytosine with 2 H 2 gas in alkaline media gave rise to [6- 2 H]-compounds almost exclusively. On the other hand, the reaction of 5-bromouracil or 5-bromocytosine with 2 H 2 gas gave rise to a mixture of [5- 2 H]-, [6- 2 H]- and [5- 2 H, 6- 2 H]-compounds depending on the experimental conditions. By controlling the temperature, the pressure of 2 H 2 gas and the amount of catalyst, [5- 2 H]-uracil and [5- 2 H]-cytosine were obtained. The isotopic distribution in each product was measured by 1 H NMR spectroscopy combined with an HPLC method. (author)

NSun2-Mediated Cytosine-5 Methylation of Vault Noncoding RNA Determines Its Processing into Regulatory Small RNAs

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Shobbir Hussain

2013-07-01

Full Text Available Autosomal-recessive loss of the NSUN2 gene has been identified as a causative link to intellectual disability disorders in humans. NSun2 is an RNA methyltransferase modifying cytosine-5 in transfer RNAs (tRNAs, yet the identification of cytosine methylation in other RNA species has been hampered by the lack of sensitive and reliable molecular techniques. Here, we describe miCLIP as an additional approach for identifying RNA methylation sites in transcriptomes. miCLIP is a customized version of the individual-nucleotide-resolution crosslinking and immunoprecipitation (iCLIP method. We confirm site-specific methylation in tRNAs and additional messenger and noncoding RNAs (ncRNAs. Among these, vault ncRNAs contained six NSun2-methylated cytosines, three of which were confirmed by RNA bisulfite sequencing. Using patient cells lacking the NSun2 protein, we further show that loss of cytosine-5 methylation in vault RNAs causes aberrant processing into Argonaute-associated small RNA fragments that can function as microRNAs. Thus, impaired processing of vault ncRNA may contribute to the etiology of NSun2-deficiency human disorders.

Molecular Imaging of Gene Expression and Efficacy following Adenoviral-Mediated Brain Tumor Gene Therapy

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Alnawaz Rehemtulla

2002-01-01

Full Text Available Cancer gene therapy is an active area of research relying upon the transfer and subsequent expression of a therapeutic transgene into tumor cells in order to provide for therapeutic selectivity. Noninvasive assessment of therapeutic response and correlation of the location, magnitude, and duration of transgene expression in vivo would be particularly useful in the development of cancer gene therapy protocols by facilitating optimization of gene transfer protocols, vector development, and prodrug dosing schedules. In this study, we developed an adenoviral vector containing both the therapeutic transgene yeast cytosine deaminase (yCD along with an optical reporter gene (luciferase. Following intratumoral injection of the vector into orthotopic 9L gliomas, anatomical and diffusion-weighted MR images were obtained over time in order to provide for quantitative assessment of overall therapeutic efficacy and spatial heterogeneity of cell kill, respectively. In addition, bioluminescence images were acquired to assess the duration and magnitude of gene expression. MR images revealed significant reduction in tumor growth rates associated with yCD/5-fluorocytosine (5FC gene therapy. Significant increases in mean tumor diffusion values were also observed during treatment with 5FC. Moreover, spatial heterogeneity in tumor diffusion changes were also observed revealing that diffusion magnetic resonance imaging could detect regional therapeutic effects due to the nonuniform delivery and/or expression of the therapeutic yCD transgene within the tumor mass. In addition, in vivo bioluminescence imaging detected luciferase gene expression, which was found to decrease over time during administration of the prodrug providing a noninvasive surrogate marker for monitoring gene expression. These results demonstrate the efficacy of the yCD/5FC strategy for the treatment of brain tumors and reveal the feasibility of using multimodality molecular and functional imaging

A Phytase-Based Reporter System for Identification of Functional Secretion Signals in Bifidobacteria

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Osswald, Annika; Westermann, Christina; Sun, Zhongke; Riedel, Christian U.

2015-01-01

Health-promoting effects have been attributed to a number of Bifidobacterium sp. strains. These effects as well as the ability to colonise the host depend on secreted proteins. Moreover, rational design of protein secretion systems bears the potential for the generation of novel probiotic bifidobacteria with improved health-promoting or therapeutic properties. To date, there is only very limited data on secretion signals of bifidobacteria available. Using in silico analysis, we demonstrate that all bifidobacteria encode the major components of Sec-dependent secretion machineries but only B. longum strains harbour Tat protein translocation systems. A reporter plasmid for secretion signals in bifidobacteria was established by fusing the coding sequence of the signal peptide of a sialidase of Bifidobacterium bifidum S17 to the phytase gene appA of E. coli. The recombinant strain showed increased phytase activity in spent culture supernatants and reduced phytase levels in crude extracts compared to the control indicating efficient phytase secretion. The reporter plasmid was used to screen seven predicted signal peptides in B. bifidum S17 and B. longum E18. The tested signal peptides differed substantially in their efficacy to mediate protein secretion in different host strains. An efficient signal peptide was used for expression and secretion of a therapeutically relevant protein in B. bifidum S17. Expression of a secreted cytosine deaminase led to a 100-fold reduced sensitivity of B. bifidum S17 to 5-fluorocytosine compared to the non-secreted cytosine deaminase suggesting efficient conversion of 5-fluorocytosine to the cytotoxic cancer drug 5-fluorouracil by cytosine deaminase occurred outside the bacterial cell. Selection of appropriate signal peptides for defined protein secretion might improve therapeutic efficacy as well as probiotic properties of bifidobacteria. PMID:26086721

A Phytase-Based Reporter System for Identification of Functional Secretion Signals in Bifidobacteria.

Directory of Open Access Journals (Sweden)

Annika Osswald

Full Text Available Health-promoting effects have been attributed to a number of Bifidobacterium sp. strains. These effects as well as the ability to colonise the host depend on secreted proteins. Moreover, rational design of protein secretion systems bears the potential for the generation of novel probiotic bifidobacteria with improved health-promoting or therapeutic properties. To date, there is only very limited data on secretion signals of bifidobacteria available. Using in silico analysis, we demonstrate that all bifidobacteria encode the major components of Sec-dependent secretion machineries but only B. longum strains harbour Tat protein translocation systems. A reporter plasmid for secretion signals in bifidobacteria was established by fusing the coding sequence of the signal peptide of a sialidase of Bifidobacterium bifidum S17 to the phytase gene appA of E. coli. The recombinant strain showed increased phytase activity in spent culture supernatants and reduced phytase levels in crude extracts compared to the control indicating efficient phytase secretion. The reporter plasmid was used to screen seven predicted signal peptides in B. bifidum S17 and B. longum E18. The tested signal peptides differed substantially in their efficacy to mediate protein secretion in different host strains. An efficient signal peptide was used for expression and secretion of a therapeutically relevant protein in B. bifidum S17. Expression of a secreted cytosine deaminase led to a 100-fold reduced sensitivity of B. bifidum S17 to 5-fluorocytosine compared to the non-secreted cytosine deaminase suggesting efficient conversion of 5-fluorocytosine to the cytotoxic cancer drug 5-fluorouracil by cytosine deaminase occurred outside the bacterial cell. Selection of appropriate signal peptides for defined protein secretion might improve therapeutic efficacy as well as probiotic properties of bifidobacteria.

Expression of activation-induced cytidine deaminase is confined to B-cell non-Hodgkin's lymphomas of germinal-center phenotype

NARCIS (Netherlands)

Smit, Laura A.; Bende, Richard J.; Aten, Jan; Guikema, Jeroen E. J.; Aarts, Wilhelmina M.; van Noesel, Carel J. M.

2003-01-01

Activation-induced cytidine deaminase (AID) is essential for somatic hypermutation and class switch recombination of the immunoglobulin (IG) genes in B cells. It has recently been proposed that AID, as the newly identified DNA mutator in man, may be instrumental in initiation and progression of

Catalytic Mechanism and Three-Dimensional Structure of Adenine Deaminase

Energy Technology Data Exchange (ETDEWEB)

Kamat, S.S.; Swaminathan, S.; Bagaria, A.; Kumaran, D.; Holmes-Hampton, G. P.; Fan, H.; Sali, A.; Sauder, J. M.; Burley, S. K.; Lindahl, P. A.; Raushel, F. M.

2011-03-22

Adenine deaminase (ADE) catalyzes the conversion of adenine to hypoxanthine and ammonia. The enzyme isolated from Escherichia coli using standard expression conditions was low for the deamination of adenine (k{sub cat} = 2.0 s{sup -1}; k{sub cat}/K{sub m} = 2.5 x 10{sup 3} M{sup -1} s{sup -1}). However, when iron was sequestered with a metal chelator and the growth medium was supplemented with Mn{sup 2+} prior to induction, the purified enzyme was substantially more active for the deamination of adenine with kcat and kcat/Km values of 200 s{sup -1} and 5 x 10{sup 5} M{sup -1} s{sup -1}, respectively. The apoenzyme was prepared and reconstituted with Fe{sup 2+}, Zn{sup 2+}, or Mn{sup 2+}. In each case, two enzyme equivalents of metal were necessary for reconstitution of the deaminase activity. This work provides the first example of any member of the deaminase subfamily of the amidohydrolase superfamily to utilize a binuclear metal center for the catalysis of a deamination reaction. [Fe{sup II}/Fe{sup II}]-ADE was oxidized to [Fe{sup III}/Fe{sup III}]-ADE with ferricyanide with inactivation of the deaminase activity. Reducing [Fe{sup III}/Fe{sup III}]-ADE with dithionite restored the deaminase activity, and thus, the diferrous form of the enzyme is essential for catalytic activity. No evidence of spin coupling between metal ions was evident by electron paramagnetic resonance or Moessbauer spectroscopy. The three-dimensional structure of adenine deaminase from Agrobacterium tumefaciens (Atu4426) was determined by X-ray crystallography at 2.2 {angstrom} resolution, and adenine was modeled into the active site on the basis of homology to other members of the amidohydrolase superfamily. On the basis of the model of the adenine-ADE complex and subsequent mutagenesis experiments, the roles for each of the highly conserved residues were proposed. Solvent isotope effects, pH-rate profiles, and solvent viscosity were utilized to propose a chemical reaction mechanism and the

Alkyladenine DNA glycosylase (Aag) in somatic hypermutation and class switch recombination.

Science.gov (United States)

Longerich, Simonne; Meira, Lisiane; Shah, Dharini; Samson, Leona D; Storb, Ursula

2007-12-01

Somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin (Ig) genes require the cytosine deaminase AID, which deaminates cytosine to uracil in Ig gene DNA. Paradoxically, proteins involved normally in error-free base excision repair and mismatch repair, seem to be co-opted to facilitate SHM and CSR, by recruiting error-prone translesion polymerases to DNA sequences containing deoxy-uracils created by AID. Major evidence supports at least one mechanism whereby the uracil glycosylase Ung removes AID-generated uracils creating abasic sites which may be used either as uninformative templates for DNA synthesis, or processed to nicks and gaps that prime error-prone DNA synthesis. We investigated the possibility that deamination at adenines also initiates SHM. Adenosine deamination would generate hypoxanthine (Hx), a substrate for the alkyladenine DNA glycosylase (Aag). Aag would generate abasic sites which then are subject to error-prone repair as above for AID-deaminated cytosine processed by Ung. If the action of an adenosine deaminase followed by Aag were responsible for significant numbers of mutations at A, we would find a preponderance of A:T>G:C transition mutations during SHM in an Aag deleted background. However, this was not observed and we found that the frequencies of SHM and CSR were not significantly altered in Aag-/- mice. Paradoxically, we found that Aag is expressed in B lymphocytes undergoing SHM and CSR and that its activity is upregulated in activated B cells. Moreover, we did find a statistically significant, albeit low increase of T:A>C:G transition mutations in Aag-/- animals, suggesting that Aag may be involved in creating the SHM A>T bias seen in wild type mice.

Discovery of a cAMP Deaminase That Quenches Cyclic AMP-Dependent Regulation

Science.gov (United States)

Goble, Alissa M.; Feng, Youjun; Raushel, Frank M.; Cronan, John E.

2013-01-01

An enzyme of unknown function within the amidohydrolase superfamily was discovered to catalyze the hydrolysis of the universal second messenger, cyclic-3’, 5’-adenosine monophosphate (cAMP). The enzyme, which we have named CadD, is encoded by the human pathogenic bacterium Leptospira interrogans. Although CadD is annotated as an adenosine deaminase, the protein specifically deaminates cAMP to cyclic-3’, 5’-inosine monophosphate (cIMP) with a kcat/Km of 2.7 ± 0.4 × 105 M−1 s−1 and has no activity on adenosine, adenine, or 5’-adenosine monophosphate (AMP). This is the first identification of a deaminase specific for cAMP. Expression of CadD in Escherichia coli mimics the loss of adenylate cyclase in that it blocks growth on carbon sources that require the cAMP-CRP transcriptional activator complex for expression of the cognate genes. The cIMP reaction product cannot replace cAMP as the ligand for CRP binding to DNA in vitro and cIMP is a very poor competitor of cAMP activation of CRP for DNA binding. Transcriptional analyses indicate that CadD expression represses expression of several cAMP-CRP dependent genes. CadD adds a new activity to the cAMP metabolic network and may be a useful tool in intracellular study of cAMP-dependent processes. PMID:24074367

HPLC-UV, MALDI-TOF-MS and ESI-MS/MS analysis of the mechlorethamine DNA crosslink at a cytosine-cytosine mismatch pair.

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Pornchai Rojsitthisak

Full Text Available Mechlorethamine [ClCH(2CH(2N(CH(3CH(2CH(2Cl], a nitrogen mustard alkylating agent, has been proven to form a DNA interstrand crosslink at a cytosine-cytosine (C-C mismatch pair using gel electrophoresis. However, the atomic connectivity of this unusual crosslink is unknown.HPLC-UV, MALDI-TOF-MS, and ESI-MS/MS were used to determine the atomic connectivity of the DNA C-C crosslink formed by mechlorethamine, MALDI-TOF-MS of the HPLC-purified reaction product of mechlorethamine with the DNA duplex d[CTCACACCGTGGTTC]•d[GAACCACCGTGTGAG] (underlined bases are a C-C mismatch pair indicated formation of an interstrand crosslink at m/z 9222.088 [M-2H+Na](+. Following enzymatic digestion of the crosslinked duplex by snake venom phosphodiesterase and calf intestinal phosphatase, ESI-MS/MS indicated the presence of dC-mech-dC [mech = CH(2CH(2N(CH(3CH(2CH(2] at m/z 269.2 [M](2+ (expected m/z 269.6, exact mass 539.27 and its hydrolytic product dC-mech-OH at m/z 329.6 [M](+ (expected m/z 329.2. Fragmentation of dC-mech-dC gave product ions at m/z 294.3 and 236.9 [M](+, which are both due to loss of the 4-amino group of cytosine (as ammonia, in addition to dC and dC+HN(CH(3CH = CH(2, respectively. The presence of m/z 269.2 [M](2+ and loss of ammonia exclude crosslink formation at cytosine N(4 or O(2 and indicate crosslinking through cytosine N(3 with formation of two quaternary ammonium ions.Our results provide an important addition to the literature, as the first example of the use of HPLC and MS for analysis of a DNA adduct at the N(3 position of cytosine.

Diversification of AID/APOBEC-like deaminases in metazoa: multiplicity of clades and widespread roles in immunity.

Science.gov (United States)

Krishnan, Arunkumar; Iyer, Lakshminarayan M; Holland, Stephen J; Boehm, Thomas; Aravind, L

2018-04-03

AID/APOBEC deaminases (AADs) convert cytidine to uridine in single-stranded nucleic acids. They are involved in numerous mutagenic processes, including those underpinning vertebrate innate and adaptive immunity. Using a multipronged sequence analysis strategy, we uncover several AADs across metazoa, dictyosteliida, and algae, including multiple previously unreported vertebrate clades, and versions from urochordates, nematodes, echinoderms, arthropods, lophotrochozoans, cnidarians, and porifera. Evolutionary analysis suggests a fundamental division of AADs early in metazoan evolution into secreted deaminases (SNADs) and classical AADs, followed by diversification into several clades driven by rapid-sequence evolution, gene loss, lineage-specific expansions, and lateral transfer to various algae. Most vertebrate AADs, including AID and APOBECs1-3, diversified in the vertebrates, whereas the APOBEC4-like clade has a deeper origin in metazoa. Positional entropy analysis suggests that several AAD clades are diversifying rapidly, especially in the positions predicted to interact with the nucleic acid target motif, and with potential viral inhibitors. Further, several AADs have evolved neomorphic metal-binding inserts, especially within loops predicted to interact with the target nucleic acid. We also observe polymorphisms, driven by alternative splicing, gene loss, and possibly intergenic recombination between paralogs. We propose that biological conflicts of AADs with viruses and genomic retroelements are drivers of rapid AAD evolution, suggesting a widespread presence of mutagenesis-based immune-defense systems. Deaminases like AID represent versions "institutionalized" from the broader array of AADs pitted in such arms races for mutagenesis of self-DNA, and similar recruitment might have independently occurred elsewhere in metazoa. Copyright © 2018 the Author(s). Published by PNAS.

Good Laboratory Practice Preclinical Safety Studies for GSK2696273 (MLV Vector-Based Ex Vivo Gene Therapy for Adenosine Deaminase Deficiency Severe Combined Immunodeficiency) in NSG Mice.

Science.gov (United States)

Carriglio, Nicola; Klapwijk, Jan; Hernandez, Raisa Jofra; Vezzoli, Michela; Chanut, Franck; Lowe, Rhiannon; Draghici, Elena; Nord, Melanie; Albertini, Paola; Cristofori, Patrizia; Richards, Jane; Staton, Hazel; Appleby, Jonathan; Aiuti, Alessandro; Sauer, Aisha V

2017-03-01

GSK2696273 (autologous CD34+ cells transduced with retroviral vector that encodes for the human adenosine deaminase [ADA] enzyme) is a gamma-retroviral ex vivo gene therapy of bone marrow-derived CD34+ cells for the treatment of adenosine deaminase deficiency severe combined immunodeficiency (ADA-SCID). ADA-SCID is a severe monogenic disease characterized by immunologic and nonimmunologic symptoms. Bone-marrow transplant from a matched related donor is the treatment of choice, but it is available for only a small proportion of patients. Ex vivo gene therapy of patient bone-marrow CD34+ cells is an alternative treatment. In order to prepare for a marketing authorization application in the European Union, preclinical safety studies in mice were requested by the European Medicines Agency (EMA). A pilot study and a main biodistribution study were performed according to Good Laboratory Practice (GLP) at the San Raffaele Telethon Institute for Gene Therapy test facility. In the main study, human umbilical cord blood (UCB)-derived CD34+ cells were transduced with gamma-retroviral vector used in the production of GSK2696273. Groups of 10 male and 10 female NOD-SCID gamma (NSG) mice were injected intravenously with a single dose of transduced- or mock-transduced UCB CD34+ cells, and they were observed for 4 months. Engraftment and multilineage differentiation of blood cells was observed in the majority of animals in both groups. There was no significant difference in the level of chimerism between the two groups. In the gene therapy group, vector was detectable in lymphohemopoietic and nonlymphohemopoietic tissues, consistent with the presence of gene-modified human hematopoietic donor cells. Given the absence of relevant safety concerns in the data, the nonclinical studies and the clinical experience with GSK2696273 supported a successful application for market authorization in the European Union for the treatment of ADA-SCID patients, for whom no suitable human leukocyte

Isolation and characterization of novel bacteria containing acc deaminase from the rhizosphere resource on dry-farming lands

International Nuclear Information System (INIS)

Zheng, P.; Tian, L.; Chen, F.; Cui, Z.

2014-01-01

Soil-microbe-plant interactions are known to be intricate and they can greatly influence the crop vigor and yield. Plant growth promoting rhizobacteria (PGPR) containing ACC deaminase can markedly affect plant metabolic processes under stress conditions. In the present study, we isolated 300 bacterial strains from the rhizosphere of maize or apple grown in drought-hit soil including four different locations of the Loess Plateau, China. Of all isolated strains, four with ACC deaminase activity (ranging from 28.88 to 155.12 nmol alpha-ketobutyrate mg-1 h-1) were further studied by determining their biological characters and sequencing the 16S rRNA gene. All four strains showed positive performance in terms of arabinose, citrate utilization, urease, indol, glucose and melibiose. In connection with the results of biochemical characters and phylogenetic analysis, these strains commonly belong to three different genera: Klebsiella, Pseudomonas and Raoultella and four different species: Klebsiella oxytoca, Klebsiella variicola, Pseudomonas fluorescens and Raoultella planticola. Although some researchers have reported their performance under stress conditions, we are the first to report Klebsiella oxytoca, Klebsiella variicola and Raoultella planticola containing ACC deaminase under drought stress. These findings are a reasonable explanation to their superb ability of causing stress-resistance in maize (Zea mays) or apple (Malus domestica) plants. The presence of diverse PGPR possessing potential ACC deaminase activity may be beneficial for enhancing crop production under different stress conditions. (author)

Adenosine Deaminase (ADA)-Deficient Severe Combined Immune Deficiency (SCID): Molecular Pathogenesis and Clinical Manifestations.

Science.gov (United States)

Bradford, Kathryn L; Moretti, Federico A; Carbonaro-Sarracino, Denise A; Gaspar, Hubert B; Kohn, Donald B

2017-10-01

Deficiency of adenosine deaminase (ADA, EC3.5.4.4), a housekeeping enzyme of purine metabolism encoded by the Ada gene, is a cause of human severe combined immune deficiency (SCID). Numerous deleterious mutations occurring in the ADA gene have been found in patients with profound lymphopenia (T - B - NK - ), thus underscoring the importance of functional purine metabolism for the development of the immune defense. While untreated ADA SCID is a fatal disorder, there are multiple life-saving therapeutic modalities to restore ADA activity and reconstitute protective immunity, including enzyme replacement therapy (ERT), allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy (GT) with autologous gene-corrected hematopoietic stem cells (HSC). We review the pathogenic mechanisms and clinical manifestations of ADA SCID.

Catalytic Mechanism and Three-Dimensional Structure of Adenine Deaminase

Energy Technology Data Exchange (ETDEWEB)

S Kamat; A Bagaria; D Kumaran; G Holmes-Hampton; H Fan; A Sali; J Sauder; S Burley; P Lindahl; et. al.

2011-12-31

Adenine deaminase (ADE) catalyzes the conversion of adenine to hypoxanthine and ammonia. The enzyme isolated from Escherichia coli using standard expression conditions was low for the deamination of adenine (k{sub cat} = 2.0 s{sup -1}; k{sub cat}/K{sub m} = 2.5 x 10{sup 3} M{sup -1} s{sup -1}). However, when iron was sequestered with a metal chelator and the growth medium was supplemented with Mn{sup 2+} prior to induction, the purified enzyme was substantially more active for the deamination of adenine with k{sub cat} and k{sub cat}/K{sub m} values of 200 s{sup -1} and 5 x 10{sup 5} M{sup -1} s{sup -1}, respectively. The apoenzyme was prepared and reconstituted with Fe{sup 2+}, Zn{sup 2+}, or Mn{sup 2+}. In each case, two enzyme equivalents of metal were necessary for reconstitution of the deaminase activity. This work provides the first example of any member of the deaminase subfamily of the amidohydrolase superfamily to utilize a binuclear metal center for the catalysis of a deamination reaction. [Fe{sup II}/Fe{sup II}]-ADE was oxidized to [Fe{sup III}/Fe{sup III}]-ADE with ferricyanide with inactivation of the deaminase activity. Reducing [Fe{sup III}/Fe{sup III}]-ADE with dithionite restored the deaminase activity, and thus, the diferrous form of the enzyme is essential for catalytic activity. No evidence of spin coupling between metal ions was evident by electron paramagnetic resonance or Moessbauer spectroscopy. The three-dimensional structure of adenine deaminase from Agrobacterium tumefaciens (Atu4426) was determined by X-ray crystallography at 2.2 {angstrom} resolution, and adenine was modeled into the active site on the basis of homology to other members of the amidohydrolase superfamily. On the basis of the model of the adenine-ADE complex and subsequent mutagenesis experiments, the roles for each of the highly conserved residues were proposed. Solvent isotope effects, pH-rate profiles, and solvent viscosity were utilized to propose a chemical reaction

Characterization of pterin deaminase from Mucor indicus MTCC 3513

Science.gov (United States)

Thandeeswaran, M.; Karthika, P.; Mahendran, R.; Palaniswamy, M.; Angayarkanni, J.

2018-03-01

Pterin deaminase is an amidohydrolase enzyme which hydrolyses pteridines to produce lumazine derivatives and ammonia. Even though the enzyme was shown as early as 1959 for its anticancer efficacy there was a long gap in the communique after that which was in 2013. In our study we have chosen Mucor indicus MTCC 3513 which was a promising strain for production of different industrial products.The pterin deaminase enzyme was harvested and extracellular from M. indicus. The extracellular sample was partially purified by using ethanol precipitation and ion exchange column (Hi-Trap QFF) in Fast Protein Liquid Chromatography. The molecular weight of the purified pterin deaminase enzyme was apparently determined by SDS-PAGE. The purified enzyme was further biochemically characterized. Molecular docking studies with the predicted sequence showed higher binding affinity towards folic acid interaction. The structure of this protein may open the windows for new drug targets for cancer therapy.

DNA Methylation Dynamics of Germinal Center B Cells Are Mediated by AID

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Pilar M. Dominguez

2015-09-01

Full Text Available Changes in DNA methylation are required for the formation of germinal centers (GCs, but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID has been recently implicated in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCBs isolated from wild-type (WT and AID-deficient (Aicda−/− mice. We determined that the transit of B cells through the GC is associated with marked locus-specific loss of methylation and increased methylation diversity, both of which are lost in Aicda−/− animals. Differentially methylated cytosines (DMCs between GCBs and naive B cells (NBs are enriched in genes that are targeted for somatic hypermutation (SHM by AID, and these genes form networks required for B cell development and proliferation. Finally, we observed significant conservation of AID-dependent epigenetic reprogramming between mouse and human B cells.

Surface study of gallium- and aluminum- doped graphenes upon adsorption of cytosine: DFT calculations

International Nuclear Information System (INIS)

Shokuhi Rad, Ali; Zareyee, Daryoush; Peyravi, Majid; Jahanshahi, Mohsen

2016-01-01

Highlights: • P1 and P4 are the most stable adsorption configurations for cytosine. • NBO analysis show n-type semiconductor property for both Al- and Ga-doped graphenes. • Important changes in the HOMO and LUMO of doped graphene upon adsorption of cytosine. • Increase in the conductivity of system when cytosine is adsorbed on doped graphenes. - Abstract: The adsorption of cytosine molecule on Al- and Ga- doped graphenes is studied using first-principles density functional theory (DFT) calculations. The energetically most stable geometries of cytosine on both Al- and Ga- doped graphenes are determined and the adsorption energies are calculated. The net charge of transfer as well as local charge of doped atoms upon adsorption of cytosine are studied by natural bond orbitals (NBO) analysis. Orbital hybridizing of complexes was searched by frontier molecular orbital theory (FMO), and density of states (DOS). Depending on the side of cytosine, there are four possible sites for its adsorption on doped graphene; denoted as P1, P2, P3, and P4, respectively. The order of binding energy in the case of Al-doped graphene is found as P1 > P4 > P3 > P2. Interestingly, the order in the case of Ga-doped graphene changes to: P4 ∼ P1 > P3 > P2. Both surfaces show superior adsorbent property, resulting chemisorption of cytosine, especially at P1 and P4 position configurations. The NBO charge analysis reveals that the charge transfers from Al- and Ga- doped graphene sheets to cytosine. The electronic properties of both surfaces undertake important changes after cytosine adsorption, which indicates notable change in its electrical conductivity.

Surface study of gallium- and aluminum- doped graphenes upon adsorption of cytosine: DFT calculations

Energy Technology Data Exchange (ETDEWEB)

Shokuhi Rad, Ali, E-mail: a.shokuhi@gmail.com [Department of Chemical Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Zareyee, Daryoush [Department of Chemistry, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of); Peyravi, Majid; Jahanshahi, Mohsen [Faculty of Chemical Engineering, Babol University of Technology, Babol (Iran, Islamic Republic of)

2016-12-30

Highlights: • P1 and P4 are the most stable adsorption configurations for cytosine. • NBO analysis show n-type semiconductor property for both Al- and Ga-doped graphenes. • Important changes in the HOMO and LUMO of doped graphene upon adsorption of cytosine. • Increase in the conductivity of system when cytosine is adsorbed on doped graphenes. - Abstract: The adsorption of cytosine molecule on Al- and Ga- doped graphenes is studied using first-principles density functional theory (DFT) calculations. The energetically most stable geometries of cytosine on both Al- and Ga- doped graphenes are determined and the adsorption energies are calculated. The net charge of transfer as well as local charge of doped atoms upon adsorption of cytosine are studied by natural bond orbitals (NBO) analysis. Orbital hybridizing of complexes was searched by frontier molecular orbital theory (FMO), and density of states (DOS). Depending on the side of cytosine, there are four possible sites for its adsorption on doped graphene; denoted as P1, P2, P3, and P4, respectively. The order of binding energy in the case of Al-doped graphene is found as P1 > P4 > P3 > P2. Interestingly, the order in the case of Ga-doped graphene changes to: P4 ∼ P1 > P3 > P2. Both surfaces show superior adsorbent property, resulting chemisorption of cytosine, especially at P1 and P4 position configurations. The NBO charge analysis reveals that the charge transfers from Al- and Ga- doped graphene sheets to cytosine. The electronic properties of both surfaces undertake important changes after cytosine adsorption, which indicates notable change in its electrical conductivity.

Gene Directed Enzyme Prodrug Therapy Using Rabbit Cytochrome P450 4B1 in Murine Colon Adenocarcinoma

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung Joo; Kang, Joo Hyun; Lee, Tae Sup; Kim, Kyeong Min; Woo, Kwang Sun; Chung, Wee Sup; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2007-07-01

The conventional cancer therapy is chemotherapy, surgical resection and/or radiotherapy. Chemotherapy using cytotoxic drug has some problems with lack of tumor selectivity resulting in toxicity to normal tissues. To enhance the tumor selectivity of cytotoxic drug, the application of suicidal gene therapy technology was designed. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a non-toxic prodrug into a cytotoxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1- tk) and cytosine deaminase (cd). Recently, a new prodrug-converting enzyme based on rabbit cytochrome P450 4B1 gene (cyp4B1) has been reported for therapy of experimental brain tumor. This enzyme activates the prodrugs such as 4-ipomeanol (4-IM) and 2- aminoanthracene (2-AA) to highly reactive furane epoxide and unsaturated dialdehyde intermediate, respectively. DNA alkylation seems to be the main mechanism of cytotoxicity of these activated drugs. In this study, we isolated cyp4B1 cDNA from rabbit lung, transduced cyp4B1 expression vector into murine colon cancer cell, and then analyzed the cytotoxic properties of cyp4b1-activated 2-AA in cyp4B1 transduced cells to verify the cyp4B1 enzyme system for gene directed enzyme prodrug therapy.

Gene Directed Enzyme Prodrug Therapy Using Rabbit Cytochrome P450 4B1 in Murine Colon Adenocarcinoma

International Nuclear Information System (INIS)

Kim, Sung Joo; Kang, Joo Hyun; Lee, Tae Sup; Kim, Kyeong Min; Woo, Kwang Sun; Chung, Wee Sup; Cheon, Gi Jeong; Choi, Chang Woon; Lim, Sang Moo

2007-01-01

The conventional cancer therapy is chemotherapy, surgical resection and/or radiotherapy. Chemotherapy using cytotoxic drug has some problems with lack of tumor selectivity resulting in toxicity to normal tissues. To enhance the tumor selectivity of cytotoxic drug, the application of suicidal gene therapy technology was designed. Suicidal gene therapy is based on the expression in tumor cells of a gene encoding an enzyme that converts a non-toxic prodrug into a cytotoxic product. Representative suicidal genes are Herpes simplex virus type 1 thymidine kinase (HSV1- tk) and cytosine deaminase (cd). Recently, a new prodrug-converting enzyme based on rabbit cytochrome P450 4B1 gene (cyp4B1) has been reported for therapy of experimental brain tumor. This enzyme activates the prodrugs such as 4-ipomeanol (4-IM) and 2- aminoanthracene (2-AA) to highly reactive furane epoxide and unsaturated dialdehyde intermediate, respectively. DNA alkylation seems to be the main mechanism of cytotoxicity of these activated drugs. In this study, we isolated cyp4B1 cDNA from rabbit lung, transduced cyp4B1 expression vector into murine colon cancer cell, and then analyzed the cytotoxic properties of cyp4b1-activated 2-AA in cyp4B1 transduced cells to verify the cyp4B1 enzyme system for gene directed enzyme prodrug therapy

Genotype-specific enrichment of ACC deaminase-positive bacteria in winter wheat rhizospheres

Science.gov (United States)

Bacteria that produce ACC deaminase promote plant growth and development by lowering levels of the stress hormone ethylene through deamination of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene. Therefore, it is hypothesized that ACC deaminase positive (ACC+) bacteri...

Adenosine deaminase production by an endophytic bacterium (Lysinibacillus sp.) from Avicennia marina.

Science.gov (United States)

Kathiresan, Kandasamy; Saravanakumar, Kandasamy; Sahu, Sunil Kumar; Sivasankaran, Muthu

2014-06-01

The present study was carried out with the following objectives: (1) to isolate the endophytic bacilli strains from the leaves of mangrove plant Avicennia marina, (2) to screen the potential strains for the production of adenosine deaminase, (3) to statistically optimize the factors that influence the enzyme activity in the potent strain, and (4) to identify the potent strain using 16S rRNA sequence and construct its phylogenetic tree. The bacterial strains isolated from the fresh leaves of a mangrove A. marina were assessed for adenosine deaminase activity by plating method. Optimization of reaction process was carried out using response surface methodology of central composite design. The potent strain was identified based on 16S rRNA sequencing and phylogeny. Of five endophytic strains, EMLK1 showed a significant deaminase activity over other four strains. The conditions for maximum activity of the isolated adenosine deaminase are described. The potent strain EMLK1 was identified as Lysinibacillus sp. (JQ710723) being the first report as a mangrove endophyte. Mangrove-derived endophytic bacillus strain Lysinibacillus sp. EMLK1 is proved to be a promising source for the production of adenosine deaminase and this enzyme deserves further studies for purification and its application in disease diagnosis.

Protein preparation and preliminary X-ray crystallographic analysis of a putative glucosamine 6-phosphate deaminase from Streptococcus mutants

Energy Technology Data Exchange (ETDEWEB)

Hu, Guan-Jing; Li, Lan-Fen; Li, Dan; Liu, Cong [National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871 (China); Wei, Shi-Cheng, E-mail: kqsc-wei@bjmu.edu.cn [Peking University School of Stomatology, Beijing 100081 (China); Liang, Yu-He, E-mail: kqsc-wei@bjmu.edu.cn; Su, Xiao-Dong [National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871 (China)

2007-09-01

A glucosamine 6-phosphate deaminase homologue from S. mutans was expressed, purified and crystallized. Diffraction data have been collected to 2.4 Å resolution. The SMU.636 protein from Streptococcus mutans is a putative glucosamine 6-phosphate deaminase with 233 residues. The smu.636 gene was PCR-amplified from S. mutans genomic DNA and cloned into the expression vector pET-28a(+). The resultant His-tagged fusion protein was expressed in Escherichia coli and purified to homogeneity in two steps. Crystals of the fusion protein were obtained by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.4 Å resolution and belong to space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 53.83, b = 82.13, c = 134.70 Å.

Protein preparation and preliminary X-ray crystallographic analysis of a putative glucosamine 6-phosphate deaminase from Streptococcus mutants

International Nuclear Information System (INIS)

Hu, Guan-Jing; Li, Lan-Fen; Li, Dan; Liu, Cong; Wei, Shi-Cheng; Liang, Yu-He; Su, Xiao-Dong

2007-01-01

A glucosamine 6-phosphate deaminase homologue from S. mutans was expressed, purified and crystallized. Diffraction data have been collected to 2.4 Å resolution. The SMU.636 protein from Streptococcus mutans is a putative glucosamine 6-phosphate deaminase with 233 residues. The smu.636 gene was PCR-amplified from S. mutans genomic DNA and cloned into the expression vector pET-28a(+). The resultant His-tagged fusion protein was expressed in Escherichia coli and purified to homogeneity in two steps. Crystals of the fusion protein were obtained by the hanging-drop vapour-diffusion method. The crystals diffracted to 2.4 Å resolution and belong to space group P2 1 2 1 2 1 , with unit-cell parameters a = 53.83, b = 82.13, c = 134.70 Å

Cytosine modifications after gamma irradiation in aerated aqueous solution of Escherichia coli DNA

International Nuclear Information System (INIS)

Polverelli, M.

1983-04-01

After gamma irradiation of cytosine in aerated aqueous solution and utilization of various spectrometric methods (mass spectrometry, proton nuclear magnetic resonance and infrared spectrometry) about ten new radiolysis products were identified. The formation of N-glycolylbiuret in H 2 18 O aqueous solution of irradiated cytosine at pH 4,5 indicated that the preferred 18 OH hydroxyl radical attack was at C-5. The formation of trans 1-carbamoyl-4,5 dihydroxyimidazolidin-2 oxo which is the major product after cytosine pyrimidine ring rearrangement took place preferentially at neutral pH, while N-glycolylbiuret predominated at pH 4,5. The deamination pathway was predominant when cytosine was irradiated at acidic pH values (pH 2 ) or in copper complexes. The development of a new acid hydrolysis method using fluorhydric acid stabilized in pyridine made easier the evaluation of cytosine modifications after gamma irradiation in aerated aqueous solution of E. Coli DNA- 14 C-2 cytosine. This hydrolytic agent removed the modified bases from the polynucleotidic chain. A difference was found between the proportion of radiolytic products removed by acid hydrolysis and by irradiation of the free base in solution [fr

Evaluation of usefulness of pleural fluid adenosine deaminase in diagnosing tuberculous pleural effusion from empyema

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Vijetha Shenoy

2014-02-01

Full Text Available Objective: To evaluate the utility of adenosine deaminase activity in the pleural fluid for the diagnosis of tuberculous pleural effusion from empyema of non-tubercular origin. Method: A retrospective analysis of data was performed on patients who were diagnosed to have tuberculous pleural effusion and empyema of non tubercular origin. Among 46 patients at Kasturba Hospital, Manipal University, Manipal, Karnataka, India, from November 201 2 to February 2013 who underwent pleural fluid adenosine deaminase estimation, 25 patients with tuberculous pleural effusion and 21 patients with empyema were diagnosed respectively. Adenosine deaminase in pleural fluid is estimated using colorimetric, Galanti and Guisti method. Results: Pleural fluid Adenosine Deaminase levels among tuberculous pleural effusion(109.38依 53.83 , empyema (141.20依71.69 with P=0.27. Conclusion: Pleural fluid adenosine deaminase alone cannot be used as a marker for the diagnosis of tuberculous pleural effusion.

Gene transfer strategies for improving radiolabeled peptide imaging and therapy

International Nuclear Information System (INIS)

Rogers, B.E.; Buchsbaum, D.J.; Zinn, K.R.

2000-01-01

Utilization of molecular biology techniques offers attractive options in nuclear medicine for improving cancer imaging and therapy with radiolabeled peptides. Two of these options include utilization of phage-panning to identify novel tumor specific peptides or single chain antibodies and gene transfer techniques to increase the antibodies and gene transfer techniques to increase the number of antigen/receptor sites expressed on malignant cells. The group has focused on the latter approach for improving radiolabeled peptide imaging and therapy. The most widely used gene transfer vectors in clinical gene therapy trials include retrovirus, cationic lipids and adenovirus. It has been utilized adenovirus vectors for gene transfer because of their ability to accomplish efficient in vivo gene transfer. Adenovirus vectors encoding the genes for a variety of antigens/receptors (carcinoembryonic antigen, gastrin-releasing peptide receptor, somatostatin receptor subtype 2 (SSTr2) have all shown that their expression is increased on cancer cells both in vitro and in vivo following adenovirus infection. Of particular interest has been the adenovirus encoding for SSTr2 (AdCMVSSTr2). Various radioisotopes have been attached to somatostatin analogues for imaging and therapy of SSTr2-positive tumors both clinically and in animal models. The use of these analogues in combination with AdCMVSSTr2 is a promising approach for improving the detection sensitivity and therapeutic efficacy of these radiolabeled peptides against solid tumors. In addition, it has been proposed the use of SSTr2 as a marker for imaging the expression of another cancer therapeutic transgene (e.g. cytosine deaminase, thymidine kinase) encoded within the same vector. This would allow for non-invasive monitoring of gene delivery to tumor sites

Human adenosine deaminase: properties and turnover in cultured T and B lymphoblasts

International Nuclear Information System (INIS)

Daddona, P.E.

1981-01-01

In this study, the properties and rate of turnover of adenosine deaminase are compared in cultured human T and B lymphoblast cell lines. 1) Relative to B lymphoblasts, the level of adenosine deaminase activity in extracts of T lymphoblast cell lines (MOLT-4, RPMI-8402, CCRF-CEM, and CCRF-HSB-2) is elevated 7-14-fold and differs by 2-fold between the C cell lines. 2) In both T and B lymphoblast extracts, the enzyme is apparently identical, based on K/sub m/ for adenosine and deoxyadenosine, K/sub i/ for inosine, V/sub max/ for adenosine, /sub S20,w/, isoelectric pH, and heat stability. Furthermore, by radioimmunoassay, the quantity of adenosine deaminase-immunocreative protein is proportional to the level of enzyme activity in all cell lines studies. 3) Using a purification and selective immunoprecipitation technique, the enzyme turnover could be assessed in cell lines labeled with [ 35 S]methionine. The apparent rate of adenosine deaminase synthesis, relative to total protein, is 2-fold faster in both T cell lines (RPMI-8402 and CCRF-CEM) than in the B cell lines (MGL-8 and GM-130). The apparent half-life (tsub1/2) for the enzyme degradation is 19 and 39 h, respectively, in CCFR-CEM and RPMI-8402, while the tsub1/2 in both B cell lines is 7-9 h. From the net rate of synthesis and degradation, the T cell lines, respectively, exhibit approximately a 6- and 12-fold difference in adenosine deaminase turnover relative to B cells, consistent with the observed differences in enzyme activity. This study suggests that while adenosine deaminase is apparently identical in both T and B lymphoblast cell lines, alterations in both the rate of enzyme synthesis and degradation contribute to its high steady state level in T cells

Mechanish of dTTP Inhibition of the Bifunctional dCTP Deaminase:dUTPase Encoded by Mycobacterium tuberculosis

DEFF Research Database (Denmark)

Helt, Signe Smedegaard; Thymark, Majbritt; Harris, Pernille

2008-01-01

Recombinant deoxycytidine triphosphate (dCTP) deaminase from Mycobacterium tuberculosis was produced in Escherichia coli and purified. The enzyme proved to be a bifunctional dCTP deaminase:deoxyuridine triphosphatase. As such, the M. tuberculosis enzyme is the second bifunctional enzyme to be cha......Recombinant deoxycytidine triphosphate (dCTP) deaminase from Mycobacterium tuberculosis was produced in Escherichia coli and purified. The enzyme proved to be a bifunctional dCTP deaminase:deoxyuridine triphosphatase. As such, the M. tuberculosis enzyme is the second bifunctional enzyme...

Prodrug Therapy for Breast Cancer Targeted by Single-Chain Antibodies F19 and 3S193

National Research Council Canada - National Science Library

Deckert, Peter

2003-01-01

... of E.coli CD with the yeast isoenzyme. In addition, a second line of fusion constructs with green fluorescent protein instead of cytosine deaminase was designed for histological and intracellular distribution studies...

ADENOSINE DEAMINASE ACTIVITY IN TYPE 2 DIABETES MELLITUS

Directory of Open Access Journals (Sweden)

Farija Peruvankuzhiyil

2017-01-01

Full Text Available BACKGROUND Altered blood levels of adenosine deaminase may help in predicting immunological dysfunction in diabetic individuals. But very few studies exist on ADA activity in type 2 diabetes mellitus. Aim of this study is to compare serum adenosine deaminase activity in type 2 diabetic patients with non-diabetic control. MATERIALS AND METHODS A comparative study design was used in data collection process. The study was conducted in 40 type 2 diabetes mellitus patients attending diabetic clinic or admitted in the medicine ward for metabolic control of diabetes in medical college, Calicut from January 2011 to January 2012. The adenosine deaminase (ADA level in the serum is measured by endpoint method in these patients. The results were expressed as mean and standard deviation. The statistical significance of the differences between the values was assessed by ANOVA. RESULTS Among 40 diabetic patients, mean ADA level in the serum is 38.56, SD±6.72 (min 30, max 53. Mean ADA level in the serum in the control group is 22.04±4.625 (min 13, max 29. CONCLUSION ADA level in the serum is found to be increased indicating its role as an important immunoenzyme marker in the aetiopathology of type 2 diabetes mellitus.

Cytosine methylation does not affect binding of transcription factor Sp1

International Nuclear Information System (INIS)

Harrington, M.A.; Jones, P.A.; Imagawa, M.; Karin, M.

1988-01-01

DNA methylation may be a component of a multilevel control mechanism that regulates eukaryotic gene expression. The authors used synthetic oligonucleotides to investigate the effect of cytosine methylation on the binding of the transcription factor Sp1 to its target sequence (a G+C-rich sequence known as a GC box). Concatemers of double-stranded 14-mers containing a GC box successfully competed with the human metallothionein IIA promoter for binding to Sp1 in DNase I protection experiments. The presence of 5-methylcytosine in the CpG sequence of the GC box did not influence Sp1 binding. The result was confirmed using double-stranded 20-mers containing 16 base pairs of complementary sequence. Electrophoretic gel retardation analysis of annealed 28-mers containing a GC box incubated with an Sp1-containing HeLa cell nuclear extract demonstrated the formation of DNA-protein complexes; formation of these complexes was not inhibited when an oligomer without a GC box was used as a competitor. Once again, the presence of a 5-methylcytosine residue in the GC box did not influence the binding of the protein to DNA. The results therefore preclude a direct effect of cytosine methylation on Sp1-DNA interactions

Acquisition of Genetic Aberrations by Activation-Induced Cytidine Deaminase (AID) during Inflammation-Associated Carcinogenesis

International Nuclear Information System (INIS)

Takai, Atsushi; Marusawa, Hiroyuki; Chiba, Tsutomu

2011-01-01

Genetic abnormalities such as nucleotide alterations and chromosomal disorders that accumulate in various tumor-related genes have an important role in cancer development. The precise mechanism of the acquisition of genetic aberrations, however, remains unclear. Activation-induced cytidine deaminase (AID), a nucleotide editing enzyme, is essential for the diversification of antibody production. AID is expressed only in activated B lymphocytes under physiologic conditions and induces somatic hypermutation and class switch recombination in immunoglobulin genes. Inflammation leads to aberrant AID expression in various gastrointestinal organs and increased AID expression contributes to cancer development by inducing genetic alterations in epithelial cells. Studies of how AID induces genetic disorders are expected to elucidate the mechanism of inflammation-associated carcinogenesis

Expression of human adenosine deaminase in mice reconstituted with retrovirus-transduced hematopoietic stem cells

International Nuclear Information System (INIS)

Wilson, J.M.; Danos, O.; Grossman, M.; Raulet, D.H.; Mulligan, R.C.

1990-01-01

Recombinant retroviruses encoding human adenosine deaminase have been used to infect murine hematopoietic stem cells. In bone marrow transplant recipients reconstituted with the genetically modified cells, human ADA was detected in peripheral blood mononuclear cells of the recipients for at least 6 months after transplantation. In animals analyzed in detail 4 months after transplantation, human ADA and proviral sequences were detected in all hematopoietic lineages; in several cases, human ADA activity exceeded the endogenous activity. These studies demonstrate the feasibility of introducing a functional human ADA gene into hematopoietic stem cells and obtaining expression in multiple hematopoietic lineages long after transplantation. This approach should be helpful in designing effective gene therapies for severe combined immunodeficiency syndromes in humans

The crystal structure of the bifunctional deaminase/reductase RibD of the riboflavin biosynthetic pathway in Escherichia coli: implications for the reductive mechanism.

Science.gov (United States)

Stenmark, Pål; Moche, Martin; Gurmu, Daniel; Nordlund, Pär

2007-10-12

We have determined the crystal structure of the bi-functional deaminase/reductase enzyme from Escherichia coli (EcRibD) that catalyzes two consecutive reactions during riboflavin biosynthesis. The polypeptide chain of EcRibD is folded into two domains where the 3D structure of the N-terminal domain (1-145) is similar to cytosine deaminase and the C-terminal domain (146-367) is similar to dihydrofolate reductase. We showed that EcRibD is dimeric and compared our structure to tetrameric RibG, an ortholog from Bacillus subtilis (BsRibG). We have also determined the structure of EcRibD in two binary complexes with the oxidized cofactor (NADP(+)) and with the substrate analogue ribose-5-phosphate (RP5) and superposed these two in order to mimic the ternary complex. Based on this superposition we propose that the invariant Asp200 initiates the reductive reaction by abstracting a proton from the bound substrate and that the pro-R proton from C4 of the cofactor is transferred to C1 of the substrate. A highly flexible loop is found in the reductase active site (159-173) that appears to control cofactor and substrate binding to the reductase active site and was therefore compared to the corresponding Met20 loop of E. coli dihydrofolate reductase (EcDHFR). Lys152, identified by comparing substrate analogue (RP5) coordination in the reductase active site of EcRibD with the homologous reductase from Methanocaldococcus jannaschii (MjaRED), is invariant among bacterial RibD enzymes and could contribute to the various pathways taken during riboflavin biosynthesis in bacteria and yeast.

DNA (Cytosine-C5) Methyltransferase Inhibition by Oligodeoxyribonucleotides Containing 2-(1H)-Pyrimidinone (Zebularine Aglycon) at the Enzymatic Target Site

OpenAIRE

van Bemmel, Dana M.; Brank, Adam S.; Eritja, Ramon; Marquez, Victor E.; Christman, Judith K.

2009-01-01

Aberrant cytosine methylation in promoter regions leads to gene silencing associated with cancer progression. A number of DNA methyltransferase inhibitors are known to reactivate silenced genes; including 5-azacytidine and 2-(1H)-pyrimidinone riboside (zebularine). Zebularine is a more stable, less cytotoxic inhibitor compared to 5-azacytidine. To determine the mechanistic basis for this difference, we carried out a detailed comparisons of the interaction between purified DNA methyltransferas...

A putative antiviral role of plant cytidine deaminases [version 2; referees: 2 approved

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Susana Martín

2017-06-01

Full Text Available Background: A mechanism of innate antiviral immunity operating against viruses infecting mammalian cells has been described during the last decade.  Host cytidine deaminases (e.g., APOBEC3 proteins edit viral genomes, giving rise to hypermutated nonfunctional viruses; consequently, viral fitness is reduced through lethal mutagenesis.  By contrast, sub-lethal hypermutagenesis may contribute to virus evolvability by increasing population diversity.  To prevent genome editing, some viruses have evolved proteins that mediate APOBEC3 degradation.  The model plant Arabidopsis thaliana genome encodes nine cytidine deaminases (AtCDAs, raising the question of whether deamination is an antiviral mechanism in plants as well. Methods: Here we tested the effects of expression of AtCDAs on the pararetrovirus Cauliflower mosaic virus (CaMV. Two different experiments were carried out. First, we transiently overexpressed each one of the nine A. thaliana AtCDA genes in Nicotiana bigelovii plants infected with CaMV, and characterized the resulting mutational spectra, comparing them with those generated under normal conditions.  Secondly, we created A. thaliana transgenic plants expressing an artificial microRNA designed to knock-out the expression of up to six AtCDA genes.  This and control plants were then infected with CaMV.  Virus accumulation and mutational spectra where characterized in both types of plants. Results:  We have shown that the A. thaliana AtCDA1 gene product exerts a mutagenic activity, significantly increasing the number of G to A mutations in vivo, with a concomitant reduction in the amount of CaMV genomes accumulated.  Furthermore, the magnitude of this mutagenic effect on CaMV accumulation is positively correlated with the level of AtCDA1 mRNA expression in the plant. Conclusions: Our results suggest that deamination of viral genomes may also work as an antiviral mechanism in plants.

The Expression and Regulation of the Cell Adhesion Molecule CD44 in Human Breast Cancer

National Research Council Canada - National Science Library

Ge, Lisheng

1997-01-01

... alternative splicing signals of CD44 variant exons as control elements in CEPT. In our colon cancer metastasis to liver model, we developed dual modulation vectors to increase tissue-specific expression of cytosine deaminase (CD...

[Isolation, identification and characterization of ACC deaminase-containing endophytic bacteria from halophyte Suaeda salsa].

Science.gov (United States)

Teng, Songshan; Liu, Yanping; Zhao, Lei

2010-11-01

We Isolated and characterized 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing endophytic bacteria from halophyte Suaeda salsa to understand the interactions between endophytes and halophyte. ACC deaminase-containing endophytic bacteria were isolated from root, stalk and leaf of Suaeda salsa and were identified based on morphological, physiological-biochemical properties, API and 16S rRNA sequence analysis. Isolates were evaluated for their ACC deaminase, antifungal, protease activity, siderophores and phytohormones, such as indole-3-acetic acid, gibberellic acid and abscisic acid production, as well as atmospheric nitrogen fixation and phosphate solubilization. Four ACC deaminase-containing endophytic bacteria strains named as LP11, SS12, TW1 and TW2 were isolated and identified as Pseudomonas oryzihabitans, Pseudomonas sp., Pantoea agglomerans and Pseudomonas putida respectively. All the strains possessed the phosphate-solubilizing ability and could produce siderophores and phytohormones more or less. None of them could fix atmospheric nitrogen or produce protease. Only strain SS12 showed antagonism against two phytopathogenic fungi viz Fusarium oxysporum f. sp. conglutinans and F. oxysporum f. sp. cucumerinum. ACC deaminase-containing endophytic bacteria of Pseudomonas sp. and Pantoea sp. isolated from halophyte Suaeda salsa have abundant biological characteristics related to plant growth promotion, stress homeostasis regulation and biocontrol activity.

Accurate CpG and non-CpG cytosine methylation analysis by high-throughput locus-specific pyrosequencing in plants.

Science.gov (United States)

How-Kit, Alexandre; Daunay, Antoine; Mazaleyrat, Nicolas; Busato, Florence; Daviaud, Christian; Teyssier, Emeline; Deleuze, Jean-François; Gallusci, Philippe; Tost, Jörg

2015-07-01

Pyrosequencing permits accurate quantification of DNA methylation of specific regions where the proportions of the C/T polymorphism induced by sodium bisulfite treatment of DNA reflects the DNA methylation level. The commercially available high-throughput locus-specific pyrosequencing instruments allow for the simultaneous analysis of 96 samples, but restrict the DNA methylation analysis to CpG dinucleotide sites, which can be limiting in many biological systems. In contrast to mammals where DNA methylation occurs nearly exclusively on CpG dinucleotides, plants genomes harbor DNA methylation also in other sequence contexts including CHG and CHH motives, which cannot be evaluated by these pyrosequencing instruments due to software limitations. Here, we present a complete pipeline for accurate CpG and non-CpG cytosine methylation analysis at single base-resolution using high-throughput locus-specific pyrosequencing. The devised approach includes the design and validation of PCR amplification on bisulfite-treated DNA and pyrosequencing assays as well as the quantification of the methylation level at every cytosine from the raw peak intensities of the Pyrograms by two newly developed Visual Basic Applications. Our method presents accurate and reproducible results as exemplified by the cytosine methylation analysis of the promoter regions of two Tomato genes (NOR and CNR) encoding transcription regulators of fruit ripening during different stages of fruit development. Our results confirmed a significant and temporally coordinated loss of DNA methylation on specific cytosines during the early stages of fruit development in both promoters as previously shown by WGBS. The manuscript describes thus the first high-throughput locus-specific DNA methylation analysis in plants using pyrosequencing.

Methylation-sensitive amplified polymorphism-based genome-wide analysis of cytosine methylation profiles in Nicotiana tabacum cultivars.

Science.gov (United States)

Jiao, J; Wu, J; Lv, Z; Sun, C; Gao, L; Yan, X; Cui, L; Tang, Z; Yan, B; Jia, Y

2015-11-26

This study aimed to investigate cytosine methylation profiles in different tobacco (Nicotiana tabacum) cultivars grown in China. Methylation-sensitive amplified polymorphism was used to analyze genome-wide global methylation profiles in four tobacco cultivars (Yunyan 85, NC89, K326, and Yunyan 87). Amplicons with methylated C motifs were cloned by reamplified polymerase chain reaction, sequenced, and analyzed. The results show that geographical location had a greater effect on methylation patterns in the tobacco genome than did sampling time. Analysis of the CG dinucleotide distribution in methylation-sensitive polymorphic restriction fragments suggested that a CpG dinucleotide cluster-enriched area is a possible site of cytosine methylation in the tobacco genome. The sequence alignments of the Nia1 gene (that encodes nitrate reductase) in Yunyan 87 in different regions indicate that a C-T transition might be responsible for the tobacco phenotype. T-C nucleotide replacement might also be responsible for the tobacco phenotype and may be influenced by geographical location.

Hypoxia-targeted suicidal gene therapy system enhances antitumor effects of radiotherapy

International Nuclear Information System (INIS)

Liu Junye; Guo Yao; Guo Guozhen

2006-01-01

Objective: To explore the effects of hypoxia-targeted suicidal gene therapy system combined with radiotherapy on pancreatic cancer. Methods: The recombinant adenovirus Ad-5HRE/hCMVmp-BCD was constructed by DNA recombinant technique. Western blot was used to detect hypoxia-induced expression of bacterial cytosine deaminase (BCD). Cell growth inhibition assay was used to determine the sensitivity of human pancreatic cancer cells MIA-PACA2 to 5-fluorocytosine (5-FC). Tumor xenograft growth delay assays was used to evaluate the effects of Ad-5HRE/hCMVmp-BCD/5-FC combined with radiotherapy on pancreatic cancer. Results: Western blot analysis demonstrated that hypoxia-induced BCD protein expression was achieved in MIA-PACA2 cells infected with Ad-5HRE/hCMVmp-BCD. With hypoxia treatment, the sensitivity of MIA-PACA2 cells infected with Ad-5HRE/hCMVmp-BCD to 5-FC significantly increased. Administration of either Ad-5HRE/hCMVmp-BCD/5-FC or radiotherapy could inhibit the growth of MIA-PACA2 xenografts in nude mice. Moreover, combination of Ad-5HRE/hCMVmp-BCD/5-FC could significantly enhance suppressing effects of radiotherapy on MIA-PACA2 xenografts. Conclusion: Hypoxia-targeted suicidal gene therapy system Ad-5HRE/hCMVmp-BCD/5-FC could enhance antitumor effects of radiotherapy on pancreatic cancer and can be used as a powerful adjunct to conventional radiotherapy. (authors)

Hydrolytic cleavage of N-6-substituted adenine derivatives by eukaryotic adenine and adenosine deaminases

Czech Academy of Sciences Publication Activity Database

Pospíšilová, H.; Šebela, M.; Novák, Ondřej; Frébort, I.

2008-01-01

Roč. 28, č. 6 (2008), s. 335-347 ISSN 0144-8463 R&D Projects: GA ČR(CZ) GA522/06/0022 Institutional research plan: CEZ:AV0Z50380511 Keywords : adenine deaminase * adenosine deaminase (ADA) * aminohydrolase Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.525, year: 2008

Inducing salt tolerance in maize through ACC-deaminase biotechnology (abstract)

International Nuclear Information System (INIS)

Shahroona, B.; Arshad, M.; Zahir, Z.A.

2005-01-01

Ethylene is one of the five established classes of phytohormones. Its involvement in evoking physiological responses in plants exposed to any kind of environmental stresses (such as salinity, drought and metal toxicity stresses) is well established, thus it has also been designated as 'stress' hormone. It is generally believed that stress induces accelerated synthesis of ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), which subsequently results in the out burst of ethylene production and plant responds to this higher level of ethylene. Thus any check on this accelerated ethylene production in plants exposed to salinity stress could help in minimizing the negative impact of this stress and plants might survive better. There are some soil bacteria which carry ACC-deaminase enzyme and their presence on root surface results in lowering the accelerated production of ethylene. Trials were conducted under axenic condition to study the effect of inoculation with ACC-deaminase containing rhizobacteria to ameliorate the effect of salinity on seedling growth. Maize seedlings were exposed to different salinity levels and results indicated that inoculation with ACC-deaminase containing rhizobacteria significantly increased root elongation, shoot length, fresh and dry weight of seedlings at all the salinity levels. (author)

Hypoxia targeted bifunctional suicide gene expression enhances radiotherapy in vitro and in vivo

International Nuclear Information System (INIS)

Sun, Xiaorong; Xing, Ligang; Deng, Xuelong; Hsiao, Hung Tsung; Manami, Akiko; Koutcher, Jason A.; Clifton Ling, C.; Li, Gloria C.

2012-01-01

Purpose: To investigate whether hypoxia targeted bifunctional suicide gene expression-cytosine deaminase (CD) and uracil phosphoribosyltransferase (UPRT) with 5-FC treatments can enhance radiotherapy. Materials and methods: Stable transfectants of R3327-AT cells were established which express a triple-fusion-gene: CD, UPRT and monomoric DsRed (mDsRed) controlled by a hypoxia inducible promoter. Hypoxia-induced expression/function of CDUPRTmDsRed was verified by western blot, flow cytometry, fluorescent microscopy, and cytotoxicity assay of 5-FU and 5-FC. Tumor-bearing mice were treated with 5-FC and local radiation. Tumor volume was monitored and compared with those treated with 5-FC or radiation alone. In addition, the CDUPRTmDsRed distribution in hypoxic regions of tumor sections was visualized with fluorescent microscopy. Results: Hypoxic induction of CDUPRTmDsRed protein correlated with increased sensitivity to 5-FC and 5-FU. Significant radiosensitization effects were detected after 5-FC treatments under hypoxic conditions. In the tumor xenografts, the distribution of CDUPRTmDsRed expression visualized with fluorescence microscopy was co-localized with the hypoxia marker pimonidazole positive staining cells. Furthermore, administration of 5-FC to mice in combination with local irradiation resulted in significant tumor regression, as in comparison with 5-FC or radiation treatments alone. Conclusions: Our data suggest that the hypoxia-inducible CDUPRT/5-FC gene therapy strategy has the ability to specifically target hypoxic cancer cells and significantly improve the tumor control in combination with radiotherapy.

Adenosine-deaminase (ADA activity in Psoriasis (A Preliminary Study

Directory of Open Access Journals (Sweden)

S D Chaudhry

1988-01-01

Full Text Available Study of adenosine-deaminase activity ′in 23 patients hav-mg psoriasis compared with an equal number of healthy controls revealed significantly high ADA-activity in the psotiatic patients.

Contributory role of adenosine deaminase in metabolic syndrome ...

African Journals Online (AJOL)

Adenosine deaminase (ADA) is an enzyme of purine metabolism commonly associated with severe combined immunodeficiency disease and believed to modulate bioactivity of insulin. Its contributory role in patients with metabolic syndrome (having features such as obesity, insulin resistance, fasting hyperglycaemia, lipid ...

Effect of suicidal gene combined with irradiation on esophageal carcinoma cell line

International Nuclear Information System (INIS)

Pan Jianji; Wang Jiezhong; Zheng Tianrong; Zheng Qiuhong

2005-01-01

Objective: As generally known that non-cytotoxic pro-drag can be transformed into cytotoxic drug by suicide gene, this work is to investigate the effect of Coli cytosine deaminase/5-fluorocytosine suicide gene (CD/5-FC) used alone or combined with irradiation in esophageal carcinoma cell line(EC). Methods: CD gene was amplified from Coli DNA genome library with PCR technique, with the eukaryotic vector pcDNA3.1-CD then constructed. ECl09 cells were transfected with pcDNA3.1-CD by liposome method. The cytotoxic effect, bystander effect and radiosensitization effect of CD/5-FC in ECl09 was analyzed. Results: The transfection of CD gene into ECl09 and its transcription was confirmed by RT-PCR method. In vitro, 5-FC showed significantly cytotoxic effect on the EPC cell transfected with CD gene. After adding 5-FC , the survival rate of cultured cell containing 5 % transfect CD gene cell was 41.8 % ± 14.2% while that in the control group was 94.6 ± 4.3 %, (t=3.14, P < 0.05). The survival rate of cultured cell containing 10% transfected CD gene cell was 37.8 ± 4.4% compared to 95.6% ± 5.4% in the control group, (t=9.75, P<0.01). CD/5-FC showed significant radiosen-sitization effect, the survival fraction of CD transfected cell was much lower in 5-FC combined with irradiation, when compared with 5-FC alone and radiotherapy alone group together, (F=11.50, P < 0.01 ). When it was compared with 5-FC alone group and irradiation alone group separately, the difference was also significant( F=4.11, P < 0.05 and F10.53, P < 0.01, respectively). Conclusions: Suicide gene CD/5-FC shows conspicuous by-stander effect and radiosensitization effect. (authors)

Patterns of cytosine methylation in an elite rice hybrid and its parental lines, detected by a methylation-sensitive amplification polymorphism technique.

Science.gov (United States)

Xiong, L Z; Xu, C G; Saghai Maroof, M A; Zhang, Q

1999-04-01

DNA methylation is known to play an important role in the regulation of gene expression in eukaryotes. In this study, we assessed the extent and pattern of cytosine methylation in the rice genome, using the technique of methylation-sensitive amplified polymorphism (MSAP), which is a modification of the amplified fragment length polymorphism (AFLP) method that makes use of the differential sensitivity of a pair of isoschizomers to cytosine methylation. The tissues assayed included seedlings and flag leaves of an elite rice hybrid, Shanyou 63, and the parental lines Zhenshan 97 and Minghui 63. In all, 1076 fragments, each representing a recognition site cleaved by either or both of the isoschizomers, were amplified using 16 pairs of selective primers. A total of 195 sites were found to be methylated at cytosines in one or both parents, and the two parents showed approximately the same overall degree of methylation (16.3%), as revealed by the incidence of differential digestion by the isoschizomers. Four classes of patterns were identified in a comparative assay of cytosine methylation in the parents and hybrid; increased methylation was detected in the hybrid compared to the parents at some of the recognition sites, while decreased methylation in the hybrid was detected at other sites. A small proportion of the sites was found to be differentially methylated in seedlings and flag leaves; DNA from young seedlings was methylated to a greater extent than that from flag leaves. Almost all of the methylation patterns detected by MSAP could be confirmed by Southern analysis using the isolated amplified fragments as probes. The results clearly demonstrate that the MSAP technique is highly efficient for large-scale detection of cytosine methylation in the rice genome. We believe that the technique can be adapted for use in other plant species.

XRCC1 suppresses somatic hypermutation and promotes alternative nonhomologous end joining in Igh genes.

Science.gov (United States)

Saribasak, Huseyin; Maul, Robert W; Cao, Zheng; McClure, Rhonda L; Yang, William; McNeill, Daniel R; Wilson, David M; Gearhart, Patricia J

2011-10-24

Activation-induced deaminase (AID) deaminates cytosine to uracil in immunoglobulin genes. Uracils in DNA can be recognized by uracil DNA glycosylase and abasic endonuclease to produce single-strand breaks. The breaks are repaired either faithfully by DNA base excision repair (BER) or mutagenically to produce somatic hypermutation (SHM) and class switch recombination (CSR). To unravel the interplay between repair and mutagenesis, we decreased the level of x-ray cross-complementing 1 (XRCC1), a scaffold protein involved in BER. Mice heterozygous for XRCC1 showed a significant increase in the frequencies of SHM in Igh variable regions in Peyer's patch cells, and of double-strand breaks in the switch regions during CSR. Although the frequency of CSR was normal in Xrcc1(+/-) splenic B cells, the length of microhomology at the switch junctions decreased, suggesting that XRCC1 also participates in alternative nonhomologous end joining. Furthermore, Xrcc1(+/-) B cells had reduced Igh/c-myc translocations during CSR, supporting a role for XRCC1 in microhomology-mediated joining. Our results imply that AID-induced single-strand breaks in Igh variable and switch regions become substrates simultaneously for BER and mutagenesis pathways.

One adenosine deaminase allele in a patient with severe combined immunodeficiency contains a point mutation abolishing enzyme activity.

OpenAIRE

Valerio, D; Dekker, B M; Duyvesteyn, M G; van der Voorn, L; Berkvens, T M; van Ormondt, H; van der Eb, A J

1986-01-01

We have cloned and sequenced an adenosine deaminase (ADA) gene from a patient with severe combined immunodeficiency (SCID) caused by inherited ADA deficiency. Two point mutations were found, resulting in amino acid substitutions at positions 80 (Lys to Arg) and 304 (Leu to Arg) of the protein. Hybridization experiments with synthetic oligonucleotide probes showed that the determined mutations are present in both DNA and RNA from the ADA-SCID patient. In addition, wild-type sequences could be ...

Genetic Variations in the Human Cannabinoid Receptor Gene Are Associated with Happiness

Science.gov (United States)

Matsunaga, Masahiro; Isowa, Tokiko; Yamakawa, Kaori; Fukuyama, Seisuke; Shinoda, Jun; Yamada, Jitsuhiro; Ohira, Hideki

2014-01-01

Happiness has been viewed as a temporary emotional state (e.g., pleasure) and a relatively stable state of being happy (subjective happiness level). As previous studies demonstrated that individuals with high subjective happiness level rated their current affective states more positively when they experience positive events, these two aspects of happiness are interrelated. According to a recent neuroimaging study, the cytosine to thymine single-nucleotide polymorphism of the human cannabinoid receptor 1 gene is associated with sensitivity to positive emotional stimuli. Thus, we hypothesized that our genetic traits, such as the human cannabinoid receptor 1 genotypes, are closely related to the two aspects of happiness. In Experiment 1, 198 healthy volunteers were used to compare the subjective happiness level between cytosine allele carriers and thymine-thymine carriers of the human cannabinoid receptor 1 gene. In Experiment 2, we used positron emission tomography with 20 healthy participants to compare the brain responses to positive emotional stimuli of cytosine allele carriers to that of thymine-thymine carriers. Compared to thymine-thymine carriers, cytosine allele carriers have a higher subjective happiness level. Regression analysis indicated that the cytosine allele is significantly associated with subjective happiness level. The positive mood after watching a positive film was significantly higher for the cytosine allele carriers compared to the thymine-thymine carriers. Positive emotion-related brain region such as the medial prefrontal cortex was significantly activated when the cytosine allele carriers watched the positive film compared to the thymine-thymine carriers. Thus, the human cannabinoid receptor 1 genotypes are closely related to two aspects of happiness. Compared to thymine-thymine carriers, the cytosine allele carriers of the human cannabinoid receptor 1 gene, who are sensitive to positive emotional stimuli, exhibited greater magnitude

Genetic variations in the human cannabinoid receptor gene are associated with happiness.

Directory of Open Access Journals (Sweden)

Masahiro Matsunaga

Full Text Available Happiness has been viewed as a temporary emotional state (e.g., pleasure and a relatively stable state of being happy (subjective happiness level. As previous studies demonstrated that individuals with high subjective happiness level rated their current affective states more positively when they experience positive events, these two aspects of happiness are interrelated. According to a recent neuroimaging study, the cytosine to thymine single-nucleotide polymorphism of the human cannabinoid receptor 1 gene is associated with sensitivity to positive emotional stimuli. Thus, we hypothesized that our genetic traits, such as the human cannabinoid receptor 1 genotypes, are closely related to the two aspects of happiness. In Experiment 1, 198 healthy volunteers were used to compare the subjective happiness level between cytosine allele carriers and thymine-thymine carriers of the human cannabinoid receptor 1 gene. In Experiment 2, we used positron emission tomography with 20 healthy participants to compare the brain responses to positive emotional stimuli of cytosine allele carriers to that of thymine-thymine carriers. Compared to thymine-thymine carriers, cytosine allele carriers have a higher subjective happiness level. Regression analysis indicated that the cytosine allele is significantly associated with subjective happiness level. The positive mood after watching a positive film was significantly higher for the cytosine allele carriers compared to the thymine-thymine carriers. Positive emotion-related brain region such as the medial prefrontal cortex was significantly activated when the cytosine allele carriers watched the positive film compared to the thymine-thymine carriers. Thus, the human cannabinoid receptor 1 genotypes are closely related to two aspects of happiness. Compared to thymine-thymine carriers, the cytosine allele carriers of the human cannabinoid receptor 1 gene, who are sensitive to positive emotional stimuli, exhibited greater

Genetic variations in the human cannabinoid receptor gene are associated with happiness.

Science.gov (United States)

Matsunaga, Masahiro; Isowa, Tokiko; Yamakawa, Kaori; Fukuyama, Seisuke; Shinoda, Jun; Yamada, Jitsuhiro; Ohira, Hideki

2014-01-01

Happiness has been viewed as a temporary emotional state (e.g., pleasure) and a relatively stable state of being happy (subjective happiness level). As previous studies demonstrated that individuals with high subjective happiness level rated their current affective states more positively when they experience positive events, these two aspects of happiness are interrelated. According to a recent neuroimaging study, the cytosine to thymine single-nucleotide polymorphism of the human cannabinoid receptor 1 gene is associated with sensitivity to positive emotional stimuli. Thus, we hypothesized that our genetic traits, such as the human cannabinoid receptor 1 genotypes, are closely related to the two aspects of happiness. In Experiment 1, 198 healthy volunteers were used to compare the subjective happiness level between cytosine allele carriers and thymine-thymine carriers of the human cannabinoid receptor 1 gene. In Experiment 2, we used positron emission tomography with 20 healthy participants to compare the brain responses to positive emotional stimuli of cytosine allele carriers to that of thymine-thymine carriers. Compared to thymine-thymine carriers, cytosine allele carriers have a higher subjective happiness level. Regression analysis indicated that the cytosine allele is significantly associated with subjective happiness level. The positive mood after watching a positive film was significantly higher for the cytosine allele carriers compared to the thymine-thymine carriers. Positive emotion-related brain region such as the medial prefrontal cortex was significantly activated when the cytosine allele carriers watched the positive film compared to the thymine-thymine carriers. Thus, the human cannabinoid receptor 1 genotypes are closely related to two aspects of happiness. Compared to thymine-thymine carriers, the cytosine allele carriers of the human cannabinoid receptor 1 gene, who are sensitive to positive emotional stimuli, exhibited greater magnitude

The combination of suicide gene therapy and radiation enhances the killing of nasopharyngeal carcinoma xenographs

International Nuclear Information System (INIS)

Xia Jiahui; Xia Kun; Feng Yong

2004-01-01

Nasopharyngeal carcinoma (NPC) is very common in Southern China and Southeast Asian countries. To explore a novel and more effective approach to NPC therapy, a combined strategy of suicide genes and radiation was designed in this study. Five suicide gene expression cassettes, yeast cytosine deaminase (CD), yeast CD/uracil phosphoribosyl-transferase (UPRT), and yeast CDglyTK gene controlled by CMV, and Egr-1 and a synthetic CMV-enhanced Egr-1 promoter (CE) were constructed in an expression vector p11MS. The expression of suicide genes in NPC CNE-2 cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. The cytotoxicity of suicide gene therapy and radiation were analyzed by MTT assay. An animal study in which yeast CD/UPRT-expressing CNE-2 tumors in nude mice were treated with 5-fluorocytosine (5-FC) and radiation was also developed. Our results revealed that p11MSCEyCD/UPRT and p11MSCEyCDglyTK are superior over three other constructs in the killing of NPC cells in vitro. We combined suicide gene-expressing tumors, 5-FC treatment, and radiation in vivo and found that the tumors greatly regressed, some disappeared completely in 3 nude mice in the yCD/UPRT group, and a significant difference of tumor volumes was observed between this group and the other four groups (p<0.05). Our results indicated that suicide gene therapy and radiation have a synergic effect on NPC therapy, and the combined strategy of radiogene therapy is of great potential as a substitute for the traditional method, radiation alone, in NPC therapies. (author)

Plasma Adenosine Deaminase Enzyme Reduces with Treatment of ...

African Journals Online (AJOL)

olayemitoyin

Plasma Adenosine Deaminase Enzyme Reduces with Treatment of Pulmonary Tuberculosis in Nigerian Patients: Indication for. Diagnosis and Treatment Monitoring. Ige O.a, Edem V.F.b and Arinola O.G.b,*. aDepartment of Medicine, University of Ibadan, Ibadan, Nigeria b Department of Chemical Pathology,. University of ...

Contributory role of adenosine deaminase in metabolic syndrome

African Journals Online (AJOL)

olayemitoyin

Cytokine balance was also changed in diet induced obese mice (Mito and Hiyosin, 2002). Although Mito et al (2000) ... immunity in man (Sadasivudu et al, 1982) adenosine deaminase modulates cell growth (Lelieuve et al, .... Colgiuri, S. (2002) The Carnivore Connection- evolution aspect of insulin resistance. Eur. J. Clin.

The genetics of feto-placental development: A study of acid phosphatase locus 1 and adenosine deaminase polymorphisms in a consecutive series of newborn infants

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Bergamaschi Antonio

2008-09-01

Full Text Available Abstract Background Acid phosphatase locus 1 and adenosine deaminase locus 1 polymorphisms show cooperative effects on glucose metabolism and immunological functions. The recent observation of cooperation between the two systems on susceptibility to repeated spontaneous miscarriage prompted us to search for possible interactional effects between these genes and the correlation between birth weight and placental weight. Deviation from a balanced development of the feto-placental unit has been found to be associated with perinatal morbidity and mortality and with cardiovascular diseases in adulthood. Methods We examined 400 consecutive newborns from the Caucasian population of Rome. Birth weight, placental weight, and gestational length were registered. Acid phosphatase locus 1 and adenosine deaminase locus 1 phenotypes were determined by starch gel electrophoresis and correlation analysis was performed by SPSS programs. Informed verbal consent to participate in the study was obtained from the mothers. Results Highly significant differences in birth weight-placental weight correlations were observed among acid phosphatase locus 1 phenotypes (p = 0.005. The correlation between birth weight and placental weight was markedly elevated in subjects carrying acid phosphatase locus 1 phenotypes with medium-low F isoform concentration (A, CA and CB phenotypes compared to those carrying acid phosphatase locus 1 phenotypes with medium-high F isoform concentration (BA and B phenotypes (p = 0.002. Environmental and developmental variables were found to exert a significant effect on birth weight-placental weight correlation in subjects with medium-high F isoform concentrations, but only a marginal effect was observed in those with medium-low F isoform concentrations. The correlation between birth weight and placental weight is higher among carriers of the adenosine deaminase locus 1 allele*2, which is associated with low activity, than in homozygous adenosine

Cytosine methylation dysregulation in neonates following intrauterine growth restriction.

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Francine Einstein

2010-01-01

Full Text Available Perturbations of the intrauterine environment can affect fetal development during critical periods of plasticity, and can increase susceptibility to a number of age-related diseases (e.g., type 2 diabetes mellitus; T2DM, manifesting as late as decades later. We hypothesized that this biological memory is mediated by permanent alterations of the epigenome in stem cell populations, and focused our studies specifically on DNA methylation in CD34+ hematopoietic stem and progenitor cells from cord blood from neonates with intrauterine growth restriction (IUGR and control subjects.Our epigenomic assays utilized a two-stage design involving genome-wide discovery followed by quantitative, single-locus validation. We found that changes in cytosine methylation occur in response to IUGR of moderate degree and involving a restricted number of loci. We also identify specific loci that are targeted for dysregulation of DNA methylation, in particular the hepatocyte nuclear factor 4alpha (HNF4A gene, a well-known diabetes candidate gene not previously associated with growth restriction in utero, and other loci encoding HNF4A-interacting proteins.Our results give insights into the potential contribution of epigenomic dysregulation in mediating the long-term consequences of IUGR, and demonstrate the value of this approach to studies of the fetal origin of adult disease.

A novel fluorescent probe (dtpa-bis(cytosine)) for detection of Eu(III) in rare earth metal ions

Science.gov (United States)

Yang, Fan; Ren, Peipei; Liu, Guanhong; Song, Youtao; Bu, Naishun; Wang, Jun

2018-03-01

In this paper, a novel fluorescent probe, dtpa-bis(cytosine), was designed and synthesized for detecting europium (Eu3 +) ion. Upon addition of Eu3 + ions into the dtpa-bis(cytosine) solution, the fluorescence intensity can strongly be enhanced. Conversely, adding other rare earth metal ions, such as Y3 +, Ce3 +, Pr3 +, Nd3 +, Sm3 +, Gd3 +, Tb3 +, Dy3 +, Ho3 +, Er3 +, Yb3 + and Lu3 +, into dtpa-bis(cytosine) solution, the fluorescence intensity is decreased slightly. Some parameters affecting the fluorescence intensity of dtpa-bis(cytosine) solution in the presence of Eu3 + ions were investigated, including solution pH value, Eu3 + ion concentration and interfering substances. The detection mechanism of Eu3 + ion using dtpa-bis(cytosine) as fluorescent probe was proposed. Under optimum conditions, the fluorescence emission intensities of EuIII-dtpa-bis(cytosine) at 375 nm in the concentration range of 0.50 × 10- 5 mol • L- 1-5.00 × 10- 5 mol • L- 1 of Eu3 + ion display a better linear relationship. The limit of detection (LOD) was determined as 8.65 × 10- 7 mol • L- 1 and the corresponding correlation coefficient (R2) of the linear equation is 0.9807. It is wished that the proposed method could be applied for sensitively and selectively detecting Eu3 + ion.

Overproduction, Purification and Characterization of Adenylate Deaminase from Aspergillus oryzae.

Science.gov (United States)

Li, Shubo; Qian, Yi; Liang, Yunlong; Chen, Xinkuan; Zhao, Mouming; Guo, Yuan; Pang, Zongwen

2016-12-01

Adenylate deaminase (AMPD, EC 3.5.4.6) is an aminohydrolase that widely used in the food and medicine industries. In this study, the gene encoding Aspergillus oryzae AMPD was cloned and expressed in Escherichia coli. Induction with 0.75 mM isopropyl β-D-l-thiogalactopyranoside resulted in an enzyme activity of 1773.9 U/mL. Recombinant AMPD was purified to electrophoretic homogeneity using nickel affinity chromatography, and its molecular weight was calculated as 78.6 kDa. Purified AMPD exhibited maximal activity at 35 °C, pH 6.0 and 30 mM K + , with apparent K m and V max values of 2.7 × 10 -4  M and 77.5 μmol/mg/min under these conditions. HPLC revealed that recombinant AMPD could effectively catalyse the synthesis of inosine-5'-monophosphate (IMP) with minimal by-products, indicating high specificity and suggesting that it could prove useful for IMP production.

Base Flip in DNA Studied by Molecular Dynamics Simulationsof Differently-Oxidized Forms of Methyl-Cytosine

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Mahdi Bagherpoor Helabad

2014-07-01

Full Text Available Distortions in the DNA sequence, such as damage or mispairs, are specifically recognized and processed by DNA repair enzymes. Many repair proteins and, in particular, glycosylases flip the target base out of the DNA helix into the enzyme’s active site. Our molecular dynamics simulations of DNA with intact and damaged (oxidized methyl-cytosine show that the probability of being flipped is similar for damaged and intact methyl-cytosine. However, the accessibility of the different 5-methyl groups allows direct discrimination of the oxidized forms. Hydrogen-bonded patterns that vary between methyl-cytosine forms carrying a carbonyl oxygen atom are likely to be detected by the repair enzymes and may thus help target site recognition.

Adenosine deaminase activity of erythrocytes in hyperuricemia

International Nuclear Information System (INIS)

Krueger, W.; Richter, V.; Beenken, O.; Weinhold, D.; Hirschberg, K.; Rotzsch, W.; Akademie der Wissenschaften der DDR, Leipzig. Zentralinstitut fuer Isotopen- und Strahlenforschung)

1982-01-01

Erythrocytic adenosine deaminase (ADA) activity was determined in 55 patients with primary hyperuricemia and in 37 healthy control persons. Unlike the controls, the ADA activity in the patient group showed a two-peak response. Hyperuricemia patients with high ADA activity also exhibited increased uric acid excretion and elevated 15 N incorporation into uric acid. High activity values of erythrocytic ADA can be interpreted as an uric acid overproduction, giving hints for a therapeutic plan. (author)

Adaptive evolution of threonine deaminase in plant defense against insect herbivores

Energy Technology Data Exchange (ETDEWEB)

Gonzales-Vigil, Eliana; Bianchetti, Christopher M.; Phillips, Jr., George N.; Howe, Gregg A. (MSU); (UW)

2011-11-07

Gene duplication is a major source of plant chemical diversity that mediates plant-herbivore interactions. There is little direct evidence, however, that novel chemical traits arising from gene duplication reduce herbivory. Higher plants use threonine deaminase (TD) to catalyze the dehydration of threonine (Thr) to {alpha}-ketobutyrate and ammonia as the committed step in the biosynthesis of isoleucine (Ile). Cultivated tomato and related Solanum species contain a duplicated TD paralog (TD2) that is coexpressed with a suite of genes involved in herbivore resistance. Analysis of TD2-deficient tomato lines showed that TD2 has a defensive function related to Thr catabolism in the gut of lepidopteran herbivores. During herbivory, the regulatory domain of TD2 is removed by proteolysis to generate a truncated protein (pTD2) that efficiently degrades Thr without being inhibited by Ile. We show that this proteolytic activation step occurs in the gut of lepidopteran but not coleopteran herbivores, and is catalyzed by a chymotrypsin-like protease of insect origin. Analysis of purified recombinant enzymes showed that TD2 is remarkably more resistant to proteolysis and high temperature than the ancestral TD1 isoform. The crystal structure of pTD2 provided evidence that electrostatic interactions constitute a stabilizing feature associated with adaptation of TD2 to the extreme environment of the lepidopteran gut. These findings demonstrate a role for gene duplication in the evolution of a plant defense that targets and co-opts herbivore digestive physiology.

The emerging role of adenosine deaminases in insects

Czech Academy of Sciences Publication Activity Database

Doleželová, Eva; Žurovec, Michal; Doležal, T.; Šimek, Petr; Bryant, P. J.

2005-01-01

Roč. 35, č. 5 (2005), s. 381-389 ISSN 0965-1748 R&D Projects: GA ČR(CZ) GA204/04/1205; GA AV ČR(CZ) IAA5007107 Grant - others:United States National Science Foundation(US) 440860-21565 Institutional research plan: CEZ:AV0Z50070508 Keywords : adenosine deaminase * ADA * growth factor Subject RIV: ED - Physiology Impact factor: 2.733, year: 2005

Cytosine Methylation Dysregulation in Neonates Following Intrauterine Growth Restriction

Science.gov (United States)

Bhagat, Tushar D.; Fazzari, Melissa J.; Verma, Amit; Barzilai, Nir; Greally, John M.

2010-01-01

Background Perturbations of the intrauterine environment can affect fetal development during critical periods of plasticity, and can increase susceptibility to a number of age-related diseases (e.g., type 2 diabetes mellitus; T2DM), manifesting as late as decades later. We hypothesized that this biological memory is mediated by permanent alterations of the epigenome in stem cell populations, and focused our studies specifically on DNA methylation in CD34+ hematopoietic stem and progenitor cells from cord blood from neonates with intrauterine growth restriction (IUGR) and control subjects. Methods and Findings Our epigenomic assays utilized a two-stage design involving genome-wide discovery followed by quantitative, single-locus validation. We found that changes in cytosine methylation occur in response to IUGR of moderate degree and involving a restricted number of loci. We also identify specific loci that are targeted for dysregulation of DNA methylation, in particular the hepatocyte nuclear factor 4α (HNF4A) gene, a well-known diabetes candidate gene not previously associated with growth restriction in utero, and other loci encoding HNF4A-interacting proteins. Conclusions Our results give insights into the potential contribution of epigenomic dysregulation in mediating the long-term consequences of IUGR, and demonstrate the value of this approach to studies of the fetal origin of adult disease. PMID:20126273

Evidence that steroid 5alpha-reductase isozyme genes are differentially methylated in human lymphocytes.

Science.gov (United States)

Rodríguez-Dorantes, M; Lizano-Soberón, M; Camacho-Arroyo, I; Calzada-León, R; Morimoto, S; Téllez-Ascencio, N; Cerbón, M A

2002-03-01

The synthesis of dihydrotestosterone (DHT) is catalyzed by steroid 5alpha-reductase isozymes 1 and 2, and this function determines the development of the male phenotype during embriogenesis and the growth of androgen sensitive tissues during puberty. The aim of this study was to determine the cytosine methylation status of 5alpha-reductase isozymes types 1 and 2 genes in normal and in 5alpha-reductase deficient men. Genomic DNA was obtained from lymphocytes of both normal subjects and patients with primary 5alpha-reductase deficiency due to point mutations in 5alpha-reductase 2 gene. Southern blot analysis of 5alpha-reductase types 1 and 2 genes from DNA samples digested with HpaII presented a different cytosine methylation pattern compared to that observed with its isoschizomer MspI, indicating that both genes are methylated in CCGG sequences. The analysis of 5alpha-reductase 1 gene from DNA samples digested with Sau3AI and its isoschizomer MboI which recognize methylation in GATC sequences showed an identical methylation pattern. In contrast, 5alpha-reductase 2 gene digested with Sau3AI presented a different methylation pattern to that of the samples digested with MboI, indicating that steroid 5alpha-reductase 2 gene possess methylated cytosines in GATC sequences. Analysis of exon 4 of 5alpha-reductase 2 gene after metabisulfite PCR showed that normal and deficient subjects present a different methylation pattern, being more methylated in patients with 5alpha-reductase 2 mutated gene. The overall results suggest that 5alpha-reductase genes 1 and 2 are differentially methylated in lymphocytes from normal and 5alpha-reductase deficient patients. Moreover, the extensive cytosine methylation pattern observed in exon 4 of 5alpha-reductase 2 gene in deficient patients, points out to an increased rate of mutations in this gene.

Metal-mediated deamination of cytosine: experiment and DFT calculations

Czech Academy of Sciences Publication Activity Database

Šponer, Judit E.; Sanz Miguel, P. J.; Rodríguez-Santiago, L.; Erxleben, A.; Krumm, M.; Sodupe, M.; Šponer, Jiří; Lippert, B.

2004-01-01

Roč. 43, č. 40 (2004), s. 5396-5399 ISSN 1433-7851 R&D Projects: GA MŠk LN00A016 Institutional research plan: CEZ:AV0Z5004920 Keywords : cytosine * deamination * density functional calculations Subject RIV: BO - Biophysics Impact factor: 9.161, year: 2004

Elastic electron scattering from the DNA bases: cytosine and thymine

International Nuclear Information System (INIS)

Colyer, C J; Bellm, S M; Lohmanny, B; Blanco, F; Garcia, G

2012-01-01

Relative elastic differential cross sections for elastic scattering from cytosine and thymine have been measured using the crossed beam method. The experimental data are compared with theoretical cross sections calculated by the screen corrected additivity rule method.

Cytosine methylation alteration in natural populations of Leymus chinensis induced by multiple abiotic stresses.

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Yingjie Yu

Full Text Available BACKGROUND: Human activity has a profound effect on the global environment and caused frequent occurrence of climatic fluctuations. To survive, plants need to adapt to the changing environmental conditions through altering their morphological and physiological traits. One known mechanism for phenotypic innovation to be achieved is environment-induced rapid yet inheritable epigenetic changes. Therefore, the use of molecular techniques to address the epigenetic mechanisms underpinning stress adaptation in plants is an important and challenging topic in biological research. In this study, we investigated the impact of warming, nitrogen (N addition, and warming+nitrogen (N addition stresses on the cytosine methylation status of Leymus chinensis Tzvel. at the population level by using the amplified fragment length polymorphism (AFLP, methylation-sensitive amplified polymorphism (MSAP and retrotransposon based sequence-specific amplification polymorphism (SSAP techniques. METHODOLOGY/PRINCIPAL FINDINGS: Our results showed that, although the percentages of cytosine methylation changes in SSAP are significantly higher than those in MSAP, all the treatment groups showed similar alteration patterns of hypermethylation and hypomethylation. It meant that the abiotic stresses have induced the alterations in cytosine methylation patterns, and the levels of cytosine methylation changes around the transposable element are higher than the other genomic regions. In addition, the identification and analysis of differentially methylated loci (DML indicated that the abiotic stresses have also caused targeted methylation changes at specific loci and these DML might have contributed to the capability of plants in adaptation to the abiotic stresses. CONCLUSIONS/SIGNIFICANCE: Our results demonstrated that abiotic stresses related to global warming and nitrogen deposition readily evoke alterations of cytosine methylation, and which may provide a molecular basis for rapid

Cytosine Methylation Alteration in Natural Populations of Leymus chinensis Induced by Multiple Abiotic Stresses

Science.gov (United States)

Yu, Yingjie; Yang, Xuejiao; Wang, Huaying; Shi, Fengxue; Liu, Ying; Liu, Jushan; Li, Linfeng; Wang, Deli; Liu, Bao

2013-01-01

Background Human activity has a profound effect on the global environment and caused frequent occurrence of climatic fluctuations. To survive, plants need to adapt to the changing environmental conditions through altering their morphological and physiological traits. One known mechanism for phenotypic innovation to be achieved is environment-induced rapid yet inheritable epigenetic changes. Therefore, the use of molecular techniques to address the epigenetic mechanisms underpinning stress adaptation in plants is an important and challenging topic in biological research. In this study, we investigated the impact of warming, nitrogen (N) addition, and warming+nitrogen (N) addition stresses on the cytosine methylation status of Leymus chinensis Tzvel. at the population level by using the amplified fragment length polymorphism (AFLP), methylation-sensitive amplified polymorphism (MSAP) and retrotransposon based sequence-specific amplification polymorphism (SSAP) techniques. Methodology/Principal Findings Our results showed that, although the percentages of cytosine methylation changes in SSAP are significantly higher than those in MSAP, all the treatment groups showed similar alteration patterns of hypermethylation and hypomethylation. It meant that the abiotic stresses have induced the alterations in cytosine methylation patterns, and the levels of cytosine methylation changes around the transposable element are higher than the other genomic regions. In addition, the identification and analysis of differentially methylated loci (DML) indicated that the abiotic stresses have also caused targeted methylation changes at specific loci and these DML might have contributed to the capability of plants in adaptation to the abiotic stresses. Conclusions/Significance Our results demonstrated that abiotic stresses related to global warming and nitrogen deposition readily evoke alterations of cytosine methylation, and which may provide a molecular basis for rapid adaptation by

Pleural effusion adenosine deaminase: a candidate biomarker to discriminate between Gram-negative and Gram-positive bacterial infections of the pleural space

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Ruolin Li

2016-05-01

Full Text Available OBJECTIVES: Delay in the treatment of pleural infection may contribute to its high mortality. In this retrospective study, we aimed to evaluate the diagnostic accuracy of pleural adenosine deaminase in discrimination between Gram-negative and Gram-positive bacterial infections of the pleural space prior to selecting antibiotics. METHODS: A total of 76 patients were enrolled and grouped into subgroups according to Gram staining: 1 patients with Gram-negative bacterial infections, aged 53.2±18.6 years old, of whom 44.7% had empyemas and 2 patients with Gram-positive bacterial infections, aged 53.5±21.5 years old, of whom 63.1% had empyemas. The pleural effusion was sampled by thoracocentesis and then sent for adenosine deaminase testing, biochemical testing and microbiological culture. The Mann-Whitney U test was used to examine the differences in adenosine deaminase levels between the groups. Correlations between adenosine deaminase and specified variables were also quantified using Spearman’s correlation coefficient. Moreover, receiver operator characteristic analysis was performed to evaluate the diagnostic accuracy of pleural effusion adenosine deaminase. RESULTS: Mean pleural adenosine deaminase levels differed significantly between Gram-negative and Gram-positive bacterial infections of the pleural space (191.8±32.1 U/L vs 81.0±16.9 U/L, p<0.01. The area under the receiver operator characteristic curve was 0.689 (95% confidence interval: 0.570, 0.792, p<0.01 at the cutoff value of 86 U/L. Additionally, pleural adenosine deaminase had a sensitivity of 63.2% (46.0-78.2%; a specificity of 73.7% (56.9-86.6%; positive and negative likelihood ratios of 2.18 and 0.50, respectively; and positive and negative predictive values of 70.6% and 66.7%, respectively. CONCLUSIONS: Pleural effusion adenosine deaminase is a helpful alternative biomarker for early and quick discrimination of Gram-negative from Gram-positive bacterial infections of the

Prodrug encapsulated albumin nanoparticles as an alternative approach to manifest anti-proliferative effects of suicide gene therapy

International Nuclear Information System (INIS)

Tirkey, Bulbul; Bhushan, Bharat; Uday Kumar, S.; Gopinath, P.

2017-01-01

Conventional anticancer agents are associated with limited therapeutic efficacy and substantial nonspecific cytotoxicity. Thus, there is an imminent need for an alternative approach that can specifically annihilate the cancer cells with minimal side effects. Among such alternative approaches, CD::UPRT (cytosine deaminase uracil phosphoribosyl transferase) suicide gene therapy has tremendous potential due to its high efficacy. Prodrug 5-Fluorocytosine (5-FC) used in combination with CD::UPRT suicide gene suffers from limited solubility which subsequently leads to decline in therapeutic efficacy. In order to overcome this, 5-FC encapsulated bovine serum albumin nanoparticles (BSA-5-FC NPs) were prepared in this work by desolvation method. Physico-chemical characterizations studies revealed amorphous nature of BSA-5-FC NPs with uniform spherical morphology. Apart from increase in solubility, encapsulated 5-FC followed slow and sustained release profile. Suicide gene expressing stable clone of L-132 cells were adapted for investigating therapeutic potential of BSA-5-FC NPs. These nanoparticles were readily taken up by the cells in a concentration dependent manner and subsequently manifested apoptosis, which was further confirmed by morphological examination and gene expression analysis. These findings clearly illustrate that CD::UPRT suicide gene therapy can be efficiently utilized in combination with this nanosystem for improved suicide gene therapy and tumor eradication. - Highlights: • In this work, BSA-5-FC NPs has been prepared to achieve its sustained release and also facilitate its uptake by cells. • A protein based system has been realized for the first time to deliver prodrug for cancer therapy. • Physico-chemical characterizations further validate the formation of spherical, monodispersed and stable nanoparticles. • The therapeutic efficacy of BSA-5-FC NPs has been validated against CD::UPRT expressing stable cells.

Prodrug encapsulated albumin nanoparticles as an alternative approach to manifest anti-proliferative effects of suicide gene therapy

Energy Technology Data Exchange (ETDEWEB)

Tirkey, Bulbul [Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Bhushan, Bharat; Uday Kumar, S. [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Gopinath, P., E-mail: pgopifnt@iitr.ernet.in [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India)

2017-04-01

Conventional anticancer agents are associated with limited therapeutic efficacy and substantial nonspecific cytotoxicity. Thus, there is an imminent need for an alternative approach that can specifically annihilate the cancer cells with minimal side effects. Among such alternative approaches, CD::UPRT (cytosine deaminase uracil phosphoribosyl transferase) suicide gene therapy has tremendous potential due to its high efficacy. Prodrug 5-Fluorocytosine (5-FC) used in combination with CD::UPRT suicide gene suffers from limited solubility which subsequently leads to decline in therapeutic efficacy. In order to overcome this, 5-FC encapsulated bovine serum albumin nanoparticles (BSA-5-FC NPs) were prepared in this work by desolvation method. Physico-chemical characterizations studies revealed amorphous nature of BSA-5-FC NPs with uniform spherical morphology. Apart from increase in solubility, encapsulated 5-FC followed slow and sustained release profile. Suicide gene expressing stable clone of L-132 cells were adapted for investigating therapeutic potential of BSA-5-FC NPs. These nanoparticles were readily taken up by the cells in a concentration dependent manner and subsequently manifested apoptosis, which was further confirmed by morphological examination and gene expression analysis. These findings clearly illustrate that CD::UPRT suicide gene therapy can be efficiently utilized in combination with this nanosystem for improved suicide gene therapy and tumor eradication. - Highlights: • In this work, BSA-5-FC NPs has been prepared to achieve its sustained release and also facilitate its uptake by cells. • A protein based system has been realized for the first time to deliver prodrug for cancer therapy. • Physico-chemical characterizations further validate the formation of spherical, monodispersed and stable nanoparticles. • The therapeutic efficacy of BSA-5-FC NPs has been validated against CD::UPRT expressing stable cells.

Optimising the utility of pleural fluid adenosine deaminase for the diagnosis of adult tuberculous pleural effusion in Hong Kong.

Science.gov (United States)

Chang, K C; Chan, M C; Leung, W M; Kong, F Y; Mak, C M; Chen, S Pl; Yu, W C

2018-02-01

Pleural fluid adenosine deaminase level can be applied to rapidly detect tuberculous pleural effusion. We aimed to establish a local diagnostic cut-off value for pleural fluid adenosine deaminase to identify patients with tuberculous pleural effusion, and optimise its utility. We retrospectively reviewed the medical records of consecutive adults with pleural fluid adenosine deaminase level measured by the Diazyme commercial kit (Diazyme Laboratories, San Diego [CA], United States) during 1 January to 31 December 2011 in a cluster of public hospitals in Hong Kong. We considered its level alongside early (within 2 weeks) findings in pleural fluid and pleural biopsy, with and without applying Light's criteria in multiple scenarios. For each scenario, we used the receiver operating characteristic curve to identify a diagnostic cut-off value for pleural fluid adenosine deaminase, and estimated its positive and negative predictive values. A total of 860 medical records were reviewed. Pleural effusion was caused by congestive heart failure, chronic renal failure, or hypoalbuminaemia caused by liver or kidney diseases in 246 (28.6%) patients, malignancy in 198 (23.0%), non-tuberculous infection in 168 (19.5%), tuberculous pleural effusion in 157 (18.3%), and miscellaneous causes in 91 (10.6%). All those with tuberculous pleural effusion had a pleural fluid adenosine deaminase level of ≤100 U/L. When analysis was restricted to 689 patients with pleural fluid adenosine deaminase level of ≤100 U/L and early negative findings for malignancy and non-tuberculous infection in pleural fluid, the positive predictive value was significantly increased and the negative predictive value non-significantly reduced. Using this approach, neither additionally restricting analysis to exudates by Light's criteria nor adding closed pleural biopsy would further enhance predictive values. As such, the diagnostic cut-off value for pleural fluid adenosine deaminase is 26.5 U/L, with a

Hyperbilirubinemia and rapid fatal hepatic failure in severe combined immunodeficiency caused by adenosine deaminase deficiency (ADA-SCID).

Science.gov (United States)

Kühl, J S; Schwarz, K; Münch, A; Schmugge, M; Pekrun, A; Meisel, C; Wahn, V; Ebell, W; von Bernuth, H

2011-03-01

Adenosin deaminase (ADA) deficiency is the cause for Severe Combined Immunodeficiency (SCID) in about 15% of patients with SCID, often presenting as T (-)B (-)NK (-)SCID. Treatment options for ADA-SCID are enzyme replacement, bone marrow transplantation or gene therapy. We here describe the first patient with ADA-SCID and fatal hepatic failure despite bone marrow transplantation from a 10/10 HLA identical related donor. As patients with ADA-SCID may be at yet underestimated increased risk for rapid hepatic failure we speculate whether hepatitis in ADA-SCID should lead to the immediate treatment with enzyme replacement by pegylated ADA. © Georg Thieme Verlag KG Stuttgart · New York.

Growth inhibition of human breast cancer cells and down-regulation of ODC1 and ADA genes by Nepeta binaloudensis

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Akbar Safipour Afshar

Full Text Available ABSTRACT Nepeta binaloudensis Jamzad, Lamiaceae, is a rare medicinal plant endemic to Iran. In spite of many studies about the chemical constituents and antibacterial effects of this species, no report has been provided about its cytotoxic and anticancer activities. In this study we have evaluated the effects of EtOH 70%, hexane and aqueous extracts of N. binaloudensis on the cell proliferation and n-hexane extract on the expression of adenosine deaminase and ornithine decarboxylase 1 genes in breast cancer cell lines (MCF-7, MDA-MB-231 compared to non-cancer line (MCF-10A. The cell lines were subjected to increasing doses of the extracts ranging from 10 to 320 µg/ml. Cell viability was quantified by MTS assay. Expression of adenosine deaminase and ornithine decarboxylase 1 genes was analyzed by real time PCR. N. binaloudensis inhibited the growth of malignant cells in a time and dose-dependent manner. Among extracts of N. binaloudensis, the hexane extract was found to be more toxic compared to other extracts. Results showed a marked decrease in the expression of ornithine decarboxylase 1 and adenosine deaminase genes in cancer cell lines. At 60 µg/ml concentration of N. binaloudensis hexane extract ornithine decarboxylase 1 and adenosine deaminase mRNA expression were reduced 4.9 fold and 3.5 fold in MCF-7 cell line and 3.6 fold and 2.6 fold in MDA-MB-231 cell line compared to control, respectively. The result of our study highlights the potential influences of N. binaloudensis hexane extract on ornithine decarboxylase 1 and adenosine deaminase genes expression in breast cancer cells and its relation to inhibition of cancer cell growth.

Diagnostic significance of adenosine deaminase in pleural tuberculosis

International Nuclear Information System (INIS)

Khurshid, R.; Shore, N.; Saleem, M.; Zameer, N.

2009-01-01

Tuberculosis (TB) is a major cause of pleural effusion, which in TB usually has lymphocytic and exudative characteristics. Analysis of adenosine deaminase (ADA) activity is a very useful diagnostic approach to achieve a more rapid and precise diagnosis in cases of Pleural TB (pTB). Fifty male and fifty female patients presenting with tuberculosis pleural effusion was included in the study. The patients were taken from the medical ward of Sir Ganga Ram Hospital between September 2001 and September 2002. Activity of Adenosine Deaminase (ADA) was estimated by the technique of Sodium dodecyl sulphate electrophoresis (SDS-EF) using 10% polyacrylamide gel. Mean age of males was 45.72+-19.22 years and of female was 43.74+-16.09 years. Mean protein level was 3.39+-0.24 g/dl in males, and it was 3.02+-0.26 g/dl in females. Mean specific gravity both in males and females was 1.020+-0.01. The results show an increased level of enzyme ADA in patients as compared to normal subjects. Estimation of ADA activity may provide basis for rapid and efficient diagnosis of pleural TB in different clinical settings. However study should be extended to larger number of patients to reach a better conclusion. (author)

Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.)

International Nuclear Information System (INIS)

Chivot, J.J.; Depernet, D.; Caen, J.

1970-01-01

We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 μM adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [fr

Double suicide genes selectively kill human umbilical vein endothelial cells

Directory of Open Access Journals (Sweden)

Liu Lunxu

2011-02-01

Full Text Available Abstract Background To construct a recombinant adenovirus containing CDglyTK double suicide genes and evaluate the killing effect of the double suicide genes driven by kinase domain insert containing receptor (KDR promoter on human umbilical vein endothelial cells. Methods Human KDR promoter, Escherichia coli (E. coli cytosine deaminase (CD gene and the herpes simplex virus-thymidine kinase (TK gene were cloned using polymerase chain reaction (PCR. Plasmid pKDR-CDglyTK was constructed with the KDR promoter and CDglyTK genes. A recombinant adenoviral plasmid AdKDR-CDglyTK was then constructed and transfected into 293 packaging cells to grow and harvest adenoviruses. KDR-expressing human umbilical vein endothelial cells (ECV304 and KDR-negative liver cancer cell line (HepG2 were infected with the recombinant adenoviruses at different multiplicity of infection (MOI. The infection rate was measured by green fluorescent protein (GFP expression. The infected cells were cultured in culture media containing different concentrations of prodrugs ganciclovir (GCV and/or 5-fluorocytosine (5-FC. The killing effects were measured using two different methods, i.e. annexin V-FITC staining and terminal transferase-mediated dUTP nick end-labeling (TUNEL staining. Results Recombinant adenoviruses AdKDR-CDglyTK were successfully constructed and they infected ECV304 and HepG2 cells efficiently. The infection rate was dependent on MOI of recombinant adenoviruses. ECV304 cells infected with AdKDR-CDglyTK were highly sensitive to GCV and 5-FC. The cell survival rate was dependent on both the concentration of the prodrugs and the MOI of recombinant adenoviruses. In contrast, there were no killing effects in the HepG2 cells. The combination of two prodrugs was much more effective in killing ECV304 cells than GCV or 5-FC alone. The growth of transgenic ECV304 cells was suppressed in the presence of prodrugs. Conclusion AdKDR-CDglyTK/double prodrog system may be a useful

The role of cytosine methylation on charge transport through a DNA strand

Energy Technology Data Exchange (ETDEWEB)

Qi, Jianqing, E-mail: jqqi@uw.edu; Anantram, M. P., E-mail: anantmp@uw.edu [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195-2500 (United States); Govind, Niranjan, E-mail: niri.govind@pnnl.gov [William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

2015-09-07

Cytosine methylation has been found to play a crucial role in various biological processes, including a number of human diseases. The detection of this small modification remains challenging. In this work, we computationally explore the possibility of detecting methylated DNA strands through direct electrical conductance measurements. Using density functional theory and the Landauer-Büttiker method, we study the electronic properties and charge transport through an eight base-pair methylated DNA strand and its native counterpart. We first analyze the effect of cytosine methylation on the tight-binding parameters of two DNA strands and then model the transmission of the electrons and conductance through the strands both with and without decoherence. We find that the main difference of the tight-binding parameters between the native DNA and the methylated DNA lies in the on-site energies of (methylated) cytosine bases. The intra- and inter-strand hopping integrals between two nearest neighboring guanine base and (methylated) cytosine base also change with the addition of the methyl groups. Our calculations show that in the phase-coherent limit, the transmission of the methylated strand is close to the native strand when the energy is nearby the highest occupied molecular orbital level and larger than the native strand by 5 times in the bandgap. The trend in transmission also holds in the presence of the decoherence with the same rate. The lower conductance for the methylated strand in the experiment is suggested to be caused by the more stable structure due to the introduction of the methyl groups. We also study the role of the exchange-correlation functional and the effect of contact coupling by choosing coupling strengths ranging from weak to strong coupling limit.

AID to overcome the limitations of genomic information by introducing somatic DNA alterations.

Science.gov (United States)

Honjo, Tasuku; Muramatsu, Masamichi; Nagaoka, Hitoshi; Kinoshita, Kazuo; Shinkura, Reiko

2006-05-01

The immune system has adopted somatic DNA alterations to overcome the limitations of the genomic information. Activation induced cytidine deaminase (AID) is an essential enzyme to regulate class switch recombination (CSR), somatic hypermutation (SHM) and gene conversion (GC) of the immunoglobulin gene. AID is known to be required for DNA cleavage of S regions in CSR and V regions in SHM. However, its molecular mechanism is a focus of extensive debate. RNA editing hypothesis postulates that AID edits yet unknown mRNA, to generate specific endonucleases for CSR and SHM. By contrast, DNA deamination hypothesis assumes that AID deaminates cytosine in DNA, followed by DNA cleavage by base excision repair enzymes. We summarize the basic knowledge for molecular mechanisms for CSR and SHM and then discuss the importance of AID not only in the immune regulation but also in the genome instability.

Polysomnographic and neurometabolic features may mark preclinical autosomal dominant cerebellar ataxia, deafness, and narcolepsy due to a mutation in the DNA (cytosine-5-)-methyltransferase gene, DNMT1.

Science.gov (United States)

Moghadam, Keivan Kaveh; Pizza, Fabio; Tonon, Caterina; Lodi, Raffaele; Carelli, Valerio; Poli, Francesca; Franceschini, Christian; Barboni, Piero; Seri, Marco; Ferrari, Simona; La Morgia, Chiara; Testa, Claudia; Cornelio, Ferdinando; Liguori, Rocco; Winkelmann, Juliane; Lin, Ling; Mignot, Emmanuel; Plazzi, Giuseppe

2014-05-01

We aimed to report the clinical picture of two asymptomatic daughters of a patient with autosomal dominant cerebellar ataxia, deafness, and narcolepsy (ADCA-DN) due to a mutation in the DNA (cytosine-5-)-methyltransferase gene, DNMT1. Clinical assessment based on history, neurologic examination, sleep recordings, neurophysiologic neuroimaging, and genetic tests was performed. History and neurologic examination in both subjects were unremarkable. Genetic analysis disclosed in both the paternally-inherited heterozygous point mutation in the DNMT1 gene. Sleep recordings found sleep-onset rapid eye movement periods (SOREMPs) and proton magnetic resonance spectroscopy (MRS) revealed increased cerebellar myoinositol (mI) in both subjects. Auditory and ophthalmologic investigations as well as structural brain magnetic resonance imaging (MRI) scans revealed no abnormalities. The two asymptomatic carriers of the heterozygous DNMT1 mutation for ADCA-DN, a late-onset neurodegenerative disease, presented with SOREMPs associated with an increase of mI in the brain, a marker of glial cell activity and density characteristic of early stages of neurodegenerative diseases. Therefore, SOREMPs may precede the clinical picture of ADCA-DN as an early polysomnographic marker of central nervous system involvement detected by MRS. Copyright © 2014 Elsevier B.V. All rights reserved.

Structure Determination of an Ag-I-Mediated Cytosine-Cytosine Base Pair within DNA Duplex in Solution with H-1/N-15/Ag-109 NMR Spectroscopy

Czech Academy of Sciences Publication Activity Database

Dairaku, T.; Furuita, K.; Sato, H.; Šebera, Jakub; Nakashima, K.; Kondo, J.; Yamanaka, D.; Kondo, Y.; Okamoto, I.; Ono, A.; Sychrovský, Vladimír; Kojima, C.; Tanaka, Y.

2016-01-01

Roč. 22, č. 37 (2016), s. 13028-13031 ISSN 0947-6539 R&D Projects: GA ČR GA13-27676S Institutional support: RVO:61388963 Keywords : NMR * Ag * cytosine * DFT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.317, year: 2016

Spectroscopic evidence for a porphobilinogen deaminase-tetrapyrrole complex that is an intermediate in the biosynthesis of uroporphyrinogen III

International Nuclear Information System (INIS)

Rose, S.; Frydman, R.B.; de los Santos, C.; Sburlati, A.; Valasinas, A.; Frydman, B.

1988-01-01

Incubation of porphobilinogen (PBG) with PBG deaminase from Rhodopseudomonas sphaeroides in carbonate buffer to total PBG consumption resulted in low yields of uroporphyrinogen I(uro'gen I). In the reaction mixture a pyrrylmethane accumulated, which at longer incubation periods was transformed into uro'gen I. The accumulated pyrrylmethane gave an Ehrlich reaction which was different from that of a 2-(aminomethyl)dipyrrylmethane or 2-(aminomethyl)tripyrrane. It resembled that of a bilane but was different from that of a 2-(hydroxymethyl)bilane. The 13 C NMR spectra of incubations carried out with [11- 13 C]PBG indicated that the pyrrylmethane was a tetrapyrrole with methylene resonances at 22.35-22.50 ppm. It was loosely bound to the deaminase, and when separated from the enzyme by gel filtration or gel electrophoresis, it immediately cyclized to uro'gen I. No enzyme-bound methylene could be detected by its chemical shift, suggesting that its line width must be very broad. When uro'gen III-cosynthase was added to the deaminase-tetrapyrrole complex, uro'gen III was formed at the expense of the latter in about 75% yield. A protonated uro'gen I structure for this intermediate was ruled out by incubations using [2,11- 13 C]PBG. Uro'gen III formation from 2-(hydroxymethyl)bilane (HMB) and from the deaminase-tetrapyrrole intermediate was compared by using deaminase-cosynthase and cosynthase from several sources. It was found that while the HMB inhibited uro'gen III formation at higher concentrations and longer incubation times, uro'gen III formation from the complex did not decrease with time

N3 and O2 Protonated Conformers of the Cytosine Mononucleotides Coexist in the Gas Phase

Science.gov (United States)

Wu, R. R.; Hamlow, L. A.; He, C. C.; Nei, Y.-w.; Berden, G.; Oomens, J.; Rodgers, M. T.

2017-08-01

The gas-phase conformations of the protonated forms of the DNA and RNA cytosine mononucleotides, [pdCyd+H]+ and [pCyd+H]+, are examined by infrared multiple photon dissociation (IRMPD) action spectroscopy over the IR fingerprint and hydrogen-stretching regions complemented by electronic structure calculations. The low-energy conformations of [pdCyd+H]+ and [pCyd+H]+ and their relative stabilities are computed at the B3LYP/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) and MP2(full)/6-311+G(2d,2p)//B3LYP/6-311+G(d,p) levels of theory. Comparisons of the measured IRMPD action spectra and B3LYP/6-311+G(d,p) linear IR spectra computed for the low-energy conformers allow the conformers present in the experiments to be determined. Similar to that found in previous IRMPD action spectroscopy studies of the protonated forms of the cytosine nucleosides, [dCyd+H]+ and [Cyd+H]+, both N3 and O2 protonated cytosine mononucleotides exhibiting an anti orientation of cytosine are found to coexist in the experimental population. The 2'-hydroxyl substituent does not significantly influence the most stable conformations of [pCyd+H]+ versus those of [pdCyd+H]+, as the IRMPD spectral profiles of [pdCyd+H]+ and [pCyd+H]+ are similar. However, the presence of the 2'-hydroxyl substituent does influence the relative intensities of the measured IRMPD bands. Comparisons to IRMPD spectroscopy studies of the deprotonated forms of the cytosine mononucleotides, [pdCyd-H]- and [pCyd-H]-, provide insight into the effects of protonation versus deprotonation on the conformational features of the nucleobase and sugar moieties. Likewise, comparisons to results of IRMPD spectroscopy studies of the protonated cytosine nucleosides provide insight into the influence of the phosphate moiety on structure. Comparison with previous ion mobility results shows the superiority of IRMPD spectroscopy for distinguishing various protonation sites.

Novel strong tissue specific promoter for gene expression in human germ cells

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Kuzmin Denis

2010-08-01

Full Text Available Abstract Background Tissue specific promoters may be utilized for a variety of applications, including programmed gene expression in cell types, tissues and organs of interest, for developing different cell culture models or for use in gene therapy. We report a novel, tissue-specific promoter that was identified and engineered from the native upstream regulatory region of the human gene NDUFV1 containing an endogenous retroviral sequence. Results Among seven established human cell lines and five primary cultures, this modified NDUFV1 upstream sequence (mNUS was active only in human undifferentiated germ-derived cells (lines Tera-1 and EP2102, where it demonstrated high promoter activity (~twice greater than that of the SV40 early promoter, and comparable to the routinely used cytomegaloviral promoter. To investigate the potential applicability of the mNUS promoter for biotechnological needs, a construct carrying a recombinant cytosine deaminase (RCD suicide gene under the control of mNUS was tested in cell lines of different tissue origin. High cytotoxic effect of RCD with a cell-death rate ~60% was observed only in germ-derived cells (Tera-1, whereas no effect was seen in a somatic, kidney-derived control cell line (HEK293. In further experiments, we tested mNUS-driven expression of a hyperactive Sleeping Beauty transposase (SB100X. The mNUS-SB100X construct mediated stable transgene insertions exclusively in germ-derived cells, thereby providing further evidence of tissue-specificity of the mNUS promoter. Conclusions We conclude that mNUS may be used as an efficient promoter for tissue-specific gene expression in human germ-derived cells in many applications. Our data also suggest that the 91 bp-long sequence located exactly upstream NDUFV1 transcriptional start site plays a crucial role in the activity of this gene promoter in vitro in the majority of tested cell types (10/12, and an important role - in the rest two cell lines.

An Escherichia coli strain deficient for both exonuclease 5 and deoxycytidine triphosphate deaminase shows enhanced sensitivity to ionizing radiation

International Nuclear Information System (INIS)

Estevenon, A.M.; Kooistra, J.; Sicard, N.

1995-01-01

An Escherichia coli mutant lacking deoxycytidine triphosphate deaminase (Dcd) activity and an unknown function encoded by a gene designated ior exhibits sensitivity to ionizing radiation whereas dcd mutants themselves are not sensitive. A DNA fragment from an E. coli genomic library that restores the wild type level of UV and gamma ray resistance to this mutant has been cloned in the multicopy vector pBR322. Comparison of its restriction map with the physical map of the E. coli chromosome revealed complete identity to the recBD genes. ior affects ATP-dependent exonuclease activity, suggesting that it is an allele of recB. This mutation alone does not confer sensitivity to UV and gamma radiation, indicating that lack of Dcd activity is also required for expression of radiation sensitivity

IRMPD Action Spectroscopy of Alkali Metal Cation-Cytosine Complexes: Effects of Alkali Metal Cation Size on Gas Phase Conformation

NARCIS (Netherlands)

Yang, B.; Wu, R.R.; Polfer, N.C.; Berden, G.; Oomens, J.; Rodgers, M.T.

2013-01-01

The gas-phase structures of alkali metal cation-cytosine complexes generated by electrospray ionization are probed via infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical calculations. IRMPD action spectra of five alkali metal cation-cytosine complexes exhibit both

Genomic DNA sequence and cytosine methylation changes of adult rice leaves after seeds space flight

Science.gov (United States)

Shi, Jinming

In this study, cytosine methylation on CCGG site and genomic DNA sequence changes of adult leaves of rice after seeds space flight were detected by methylation-sensitive amplification polymorphism (MSAP) and Amplified fragment length polymorphism (AFLP) technique respectively. Rice seeds were planted in the trial field after 4 days space flight on the shenzhou-6 Spaceship of China. Adult leaves of space-treated rice including 8 plants chosen randomly and 2 plants with phenotypic mutation were used for AFLP and MSAP analysis. Polymorphism of both DNA sequence and cytosine methylation were detected. For MSAP analysis, the average polymorphic frequency of the on-ground controls, space-treated plants and mutants are 1.3%, 3.1% and 11% respectively. For AFLP analysis, the average polymorphic frequencies are 1.4%, 2.9%and 8%respectively. Total 27 and 22 polymorphic fragments were cloned sequenced from MSAP and AFLP analysis respectively. Nine of the 27 fragments from MSAP analysis show homology to coding sequence. For the 22 polymorphic fragments from AFLP analysis, no one shows homology to mRNA sequence and eight fragments show homology to repeat region or retrotransposon sequence. These results suggest that although both genomic DNA sequence and cytosine methylation status can be effected by space flight, the genomic region homology to the fragments from genome DNA and cytosine methylation analysis were different.

A colorimetric assay of 1-aminocyclopropane-1-carboxylate (ACC) based on ninhydrin reaction for rapid screening of bacteria containing ACC deaminase.

Science.gov (United States)

Li, Z; Chang, S; Lin, L; Li, Y; An, Q

2011-08-01

1-Aminocyclopropane-1-carboxylate (ACC) deaminase activity is an efficient marker for bacteria to promote plant growth by lowering ethylene levels in plants. We aim to develop a method for rapidly screening bacteria containing ACC deaminase, based on a colorimetric ninhydrin assay of ACC. A reliable colorimetric ninhydrin assay was developed to quantify ACC using heat-resistant polypropylene chimney-top 96-well PCR plates, having the wells evenly heated in boiling water, preventing accidental contamination from boiling water and limiting evaporation. With this method to measure bacterial consumption of ACC, 44 ACC-utilizing bacterial isolates were rapidly screened out from 311 bacterial isolates that were able to grow on minimal media containing ACC as the sole nitrogen source. The 44 ACC-utilizing bacterial isolates showed ACC deaminase activities and belonged to the genus Burkholderia, Pseudomonas or Herbaspirillum. Determination of bacterial ACC consumption by the PCR-plate ninhydrin-ACC assay is a rapid and efficient method for screening bacteria containing ACC deaminase from a large number of bacterial isolates. The PCR-plate ninhydrin-ACC assay extends the utility of the ninhydrin reaction and enables a rapid screening of bacteria containing ACC deaminase from large numbers of bacterial isolates. © 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

ACC deaminase and IAA producing growth promoting bacteria from the rhizosphere soil of tropical rice plants.

Science.gov (United States)

Bal, Himadri Bhusan; Das, Subhasis; Dangar, Tushar K; Adhya, Tapan K

2013-12-01

Beneficial plant-associated bacteria play a key role in supporting and/or promoting plant growth and health. Plant growth promoting bacteria present in the rhizosphere of crop plants can directly affect plant metabolism or modulate phytohormone production or degradation. We isolated 355 bacteria from the rhizosphere of rice plants grown in the farmers' fields in the coastal rice field soil from five different locations of the Ganjam district of Odisha, India. Six bacteria producing both ACC deaminase (ranging from 603.94 to 1350.02 nmol α-ketobutyrate mg(-1)  h(-1) ) and indole acetic acid (IAA; ranging from 10.54 to 37.65 μM ml(-1) ) in pure cultures were further identified using polyphasic taxonomy including BIOLOG((R)) , FAME analysis and the 16S rRNA gene sequencing. Phylogenetic analyses of the isolates resulted into five major clusters to include members of the genera Bacillus, Microbacterium, Methylophaga, Agromyces, and Paenibacillus. Seed inoculation of rice (cv. Naveen) by the six individual PGPR isolates had a considerable impact on different growth parameters including root elongation that was positively correlated with ACC deaminase activity and IAA production. The cultures also had other plant growth attributes including ammonia production and at least two isolates produced siderophores. Study indicates that presence of diverse rhizobacteria with effective growth-promoting traits, in the rice rhizosphere, may be exploited for a sustainable crop management under field conditions. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Activation-induced deoxycytidine deaminase (AID) co-transcriptional scanning at single-molecule resolution

Science.gov (United States)

Senavirathne, Gayan; Bertram, Jeffrey G.; Jaszczur, Malgorzata; Chaurasiya, Kathy R.; Pham, Phuong; Mak, Chi H.; Goodman, Myron F.; Rueda, David

2015-12-01

Activation-induced deoxycytidine deaminase (AID) generates antibody diversity in B cells by initiating somatic hypermutation (SHM) and class-switch recombination (CSR) during transcription of immunoglobulin variable (IgV) and switch region (IgS) DNA. Using single-molecule FRET, we show that AID binds to transcribed dsDNA and translocates unidirectionally in concert with RNA polymerase (RNAP) on moving transcription bubbles, while increasing the fraction of stalled bubbles. AID scans randomly when constrained in an 8 nt model bubble. When unconstrained on single-stranded (ss) DNA, AID moves in random bidirectional short slides/hops over the entire molecule while remaining bound for ~5 min. Our analysis distinguishes dynamic scanning from static ssDNA creasing. That AID alone can track along with RNAP during transcription and scan within stalled transcription bubbles suggests a mechanism by which AID can initiate SHM and CSR when properly regulated, yet when unregulated can access non-Ig genes and cause cancer.

Mutations in the gene for methylenetetrahydrofolate reductase, homocysteine levels, and vitamin status in women with a history of preeclampsia

NARCIS (Netherlands)

Lachmeijer, AMA; Arngrimsson, R; Bastiaans, EJ; Pals, G; ten Kate, LP; de Vries, JIP; Kostense, PJ; Aarnoudse, JG; Dekker, GA

OBJECTIVE: This study was undertaken to assess frequencies of the methylenetetrahydrofolate reductase gene mutations cytosine-to-thymine substitution at base 677 (C677T) and adenine-to-cytosine substitution at base 1298 (A1298C) and their interactions with homocysteine and vitamin levels among Dutch

Gene Therapy in Cardiac Arrhythmias

OpenAIRE

Praveen, S.V; Francis, Johnson; Venugopal, K

2006-01-01

Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within the left bundle branch can provide stable heart rates. Genetic modification of the AV...

Transgenerational epigenetics: Inheritance of global cytosine methylation and methylation-related epigenetic markers in the shrub Lavandula latifolia.

Science.gov (United States)

Herrera, Carlos M; Alonso, Conchita; Medrano, Mónica; Pérez, Ricardo; Bazaga, Pilar

2018-04-01

The ecological and evolutionary significance of natural epigenetic variation (i.e., not based on DNA sequence variants) variation will depend critically on whether epigenetic states are transmitted from parents to offspring, but little is known on epigenetic inheritance in nonmodel plants. We present a quantitative analysis of transgenerational transmission of global DNA cytosine methylation (= proportion of all genomic cytosines that are methylated) and individual epigenetic markers (= methylation status of anonymous MSAP markers) in the shrub Lavandula latifolia. Methods based on parent-offspring correlations and parental variance component estimation were applied to epigenetic features of field-growing plants ('maternal parents') and greenhouse-grown progenies. Transmission of genetic markers (AFLP) was also assessed for reference. Maternal parents differed significantly in global DNA cytosine methylation (range = 21.7-36.7%). Greenhouse-grown maternal families differed significantly in global methylation, and their differences were significantly related to maternal origin. Methylation-sensitive amplified polymorphism (MSAP) markers exhibited significant transgenerational transmission, as denoted by significant maternal variance component of marker scores in greenhouse families and significant mother-offspring correlations of marker scores. Although transmission-related measurements for global methylation and MSAP markers were quantitatively lower than those for AFLP markers taken as reference, this study has revealed extensive transgenerational transmission of genome-wide global cytosine methylation and anonymous epigenetic markers in L. latifolia. Similarity of results for global cytosine methylation and epigenetic markers lends robustness to this conclusion, and stresses the value of considering both types of information in epigenetic studies of nonmodel plants. © 2018 Botanical Society of America.

Glucose metabolism during fasting is altered in experimental porphobilinogen deaminase deficiency.

Science.gov (United States)

Collantes, María; Serrano-Mendioroz, Irantzu; Benito, Marina; Molinet-Dronda, Francisco; Delgado, Mercedes; Vinaixa, María; Sampedro, Ana; Enríquez de Salamanca, Rafael; Prieto, Elena; Pozo, Miguel A; Peñuelas, Iván; Corrales, Fernando J; Barajas, Miguel; Fontanellas, Antonio

2016-04-01

Porphobilinogen deaminase (PBGD) haploinsufficiency (acute intermittent porphyria, AIP) is characterized by neurovisceral attacks when hepatic heme synthesis is activated by endogenous or environmental factors including fasting. While the molecular mechanisms underlying the nutritional regulation of hepatic heme synthesis have been described, glucose homeostasis during fasting is poorly understood in porphyria. Our study aimed to analyse glucose homeostasis and hepatic carbohydrate metabolism during fasting in PBGD-deficient mice. To determine the contribution of hepatic PBGD deficiency to carbohydrate metabolism, AIP mice injected with a PBGD-liver gene delivery vector were included. After a 14 h fasting period, serum and liver metabolomics analyses showed that wild-type mice stimulated hepatic glycogen degradation to maintain glucose homeostasis while AIP livers activated gluconeogenesis and ketogenesis due to their inability to use stored glycogen. The serum of fasted AIP mice showed increased concentrations of insulin and reduced glucagon levels. Specific over-expression of the PBGD protein in the liver tended to normalize circulating insulin and glucagon levels, stimulated hepatic glycogen catabolism and blocked ketone body production. Reduced glucose uptake was observed in the primary somatosensorial brain cortex of fasted AIP mice, which could be reversed by PBGD-liver gene delivery. In conclusion, AIP mice showed a different response to fasting as measured by altered carbohydrate metabolism in the liver and modified glucose consumption in the brain cortex. Glucose homeostasis in fasted AIP mice was efficiently normalized after restoration of PBGD gene expression in the liver. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cytosine arabinoside enhancement of gamma irradiation induced mutations in human T-lymphocytes

International Nuclear Information System (INIS)

O'Neill, J.P.; Sullivan, L.M.; Hunter, T.C.; Nicklas, J.A.

1991-01-01

The frequency of 6-thioguanine resistant (TGr) mutants induced in human G0 phase T-lymphocytes by 200 cGy of gamma irradiation is greatly enhanced by incubation with cytosine arabinoside (ara-C) after irradiation. The mutant frequency increased with increasing incubation time in ara-C for up to 2 hr. This mutation induction required a phenotypic expression time of 5-8 days mass culture growth, similar to that found with mutants induced by 300 cGy of irradiation alone. Southern blot analysis of 40 isolated mutant clones revealed 8 independent mutations by T-cell receptor (TCR) gene rearrangement patterns. Four of these eight showed hprt gene structural alterations (0.50). An alternative method to allow phenotypic expression was developed to minimize the isolation of hprt/TCR sibling mutants. The use of in situ expression in the microtiter dish wells resulted in the isolation of 17 independent mutations in 19 mutant clones. Ten of these 17 mutations showed hprt structural alterations (0.59). The high fraction of mutations involving structural alterations detected by Southern blot analysis is consistent with the known induction of chromosome aberrations by irradiation plus ara-C treatment. We propose that both the increase in Mf and the increase in the incidence of hprt gene structural alterations are due to the accumulation of strand breaks in repairing regions of DNA under these conditions of ara-C induced inhibition of repair. We further propose that upon release of the ara-C inhibition, these repairing regions can interact to yield both gene mutations and chromosome aberrations

Excision of deaminated cytosine from the vertebrate genome: role of the SMUG1 uracil–DNA glycosylase

Science.gov (United States)

Nilsen, Hilde; Haushalter, Karl A.; Robins, Peter; Barnes, Deborah E.; Verdine, Gregory L.; Lindahl, Tomas

2001-01-01

Gene-targeted mice deficient in the evolutionarily conserved uracil–DNA glycosylase encoded by the UNG gene surprisingly lack the mutator phenotype characteristic of bacterial and yeast ung– mutants. A complementary uracil–DNA glycosylase activity detected in ung–/– murine cells and tissues may be responsible for the repair of deaminated cytosine residues in vivo. Here, specific neutralizing antibodies were used to identify the SMUG1 enzyme as the major uracil–DNA glycosylase in UNG-deficient mice. SMUG1 is present at similar levels in cell nuclei of non-proliferating and proliferating tissues, indicating a replication- independent role in DNA repair. The SMUG1 enzyme is found in vertebrates and insects, whereas it is absent in nematodes, plants and fungi. We propose a model in which SMUG1 has evolved in higher eukaryotes as an anti-mutator distinct from the UNG enzyme, the latter being largely localized to replication foci in mammalian cells to counteract de novo dUMP incorporation into DNA. PMID:11483530

Three-dimensional tumor spheroids for in vitro analysis of bacteria as gene delivery vectors in tumor therapy.

Science.gov (United States)

Osswald, Annika; Sun, Zhongke; Grimm, Verena; Ampem, Grace; Riegel, Karin; Westendorf, Astrid M; Sommergruber, Wolfgang; Otte, Kerstin; Dürre, Peter; Riedel, Christian U

2015-12-12

Several studies in animal models demonstrated that obligate and facultative anaerobic bacteria of the genera Bifidobacterium, Salmonella, or Clostridium specifically colonize solid tumors. Consequently, these and other bacteria are discussed as live vectors to deliver therapeutic genes to inhibit tumor growth. Therapeutic approaches for cancer treatment using anaerobic bacteria have been investigated in different mouse models. In the present study, solid three-dimensional (3D) multicellular tumor spheroids (MCTS) of the colorectal adenocarcinoma cell line HT-29 were generated and tested for their potential to study prodrug-converting enzyme therapies using bacterial vectors in vitro. HT-29 MCTS resembled solid tumors displaying all relevant features with an outer zone of proliferating cells and hypoxic and apoptotic regions in the core. Upon incubation with HT-29 MCTS, Bifidobacterium bifidum S17 and Salmonella typhimurium YB1 selectively localized, survived and replicated in hypoxic areas inside MCTS. Furthermore, spores of the obligate anaerobe Clostridium sporogenes germinated in these hypoxic areas. To further evaluate the potential of MCTS to investigate therapeutic approaches using bacteria as gene delivery vectors, recombinant bifidobacteria expressing prodrug-converting enzymes were used. Expression of a secreted cytosine deaminase in combination with 5-fluorocytosine had no effect on growth of MCTS due to an intrinsic resistance of HT-29 cells to 5-fluorouracil, i.e. the converted drug. However, a combination of the prodrug CB1954 and a strain expressing a secreted chromate reductase effectively inhibited MCTS growth. Collectively, the presented results indicate that MCTS are a suitable and reliable model to investigate live bacteria as gene delivery vectors for cancer therapy in vitro.

[Triplet expansion cytosine-guanine-guanine: Three cases of OMIM syndrome in the same family].

Science.gov (United States)

González-Pérez, Jesús; Izquierdo-Álvarez, Silvia; Fuertes-Rodrigo, Cristina; Monge-Galindo, Lorena; Peña-Segura, José Luis; López-Pisón, Francisco Javier

2016-04-01

The dynamic increase in the number of triplet repeats of cytosine-guanine-guanine (CGG) in the FMR1 gene mutation is responsible for three OMIM syndromes with a distinct clinical phenotype: Fragile X syndrome (FXS) and two pathologies in adult carriers of the premutation (55-200 CGG repeats): Primary ovarian insufficiency (FXPOI) and tremor-ataxia syndrome (FXTAS) associated with FXS. CGG mutation dynamics of the FMR1 gene were studied in DNA samples from peripheral blood from the index case and other relatives of first, second and third degree by TP-PCR, and the percentage methylation. Diagnosis of FXS was confirmed in three patients (21.4%), eight patients (57.1%) were confirmed in the premutation range transmitters, one male patient with full mutation/permutation mosaicism (7.1%) and two patients (14.3%) with normal study. Of the eight permutated patients, three had FXPOI and one male patient had FXTAS. Our study suggests the importance of making an early diagnosis of SXF in order to carry out a family study and genetic counselling, which allow the identification of new cases or premutated patients with FMR1 gene- associated syndromes (FXTAS, FXPOI). Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

RNA-mediated epigenetic heredity requires the cytosine methyltransferase Dnmt2.

Directory of Open Access Journals (Sweden)

Jafar Kiani

2013-05-01

Full Text Available RNA-mediated transmission of phenotypes is an important way to explain non-Mendelian heredity. We have previously shown that small non-coding RNAs can induce hereditary epigenetic variations in mice and act as the transgenerational signalling molecules. Two prominent examples for these paramutations include the epigenetic modulation of the Kit gene, resulting in altered fur coloration, and the modulation of the Sox9 gene, resulting in an overgrowth phenotype. We now report that expression of the Dnmt2 RNA methyltransferase is required for the establishment and hereditary maintenance of both paramutations. Our data show that the Kit paramutant phenotype was not transmitted to the progeny of Dnmt2(-/- mice and that the Sox9 paramutation was also not established in Dnmt2(-/- embryos. Similarly, RNA from Dnmt2-negative Kit heterozygotes did not induce the paramutant phenotype when microinjected into Dnmt2-deficient fertilized eggs and microinjection of the miR-124 microRNA failed to induce the characteristic giant phenotype. In agreement with an RNA-mediated mechanism of inheritance, no change was observed in the DNA methylation profiles of the Kit locus between the wild-type and paramutant mice. RNA bisulfite sequencing confirmed Dnmt2-dependent tRNA methylation in mouse sperm and also indicated Dnmt2-dependent cytosine methylation in Kit RNA in paramutant embryos. Together, these findings uncover a novel function of Dnmt2 in RNA-mediated epigenetic heredity.

Information Thermodynamics of Cytosine DNA Methylation.

Directory of Open Access Journals (Sweden)

Robersy Sanchez

Full Text Available Cytosine DNA methylation (CDM is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background ("noise" induced by thermal fluctuations. Here, we propose a novel statistical and information thermodynamic description of the CDM changes to address the last question. The physical basis of our statistical mechanical model was evaluated in two respects: 1 the adherence to Landauer's principle, according to which molecular machines must dissipate a minimum energy ε = kBT ln2 at each logic operation, where kB is the Boltzmann constant, and T is the absolute temperature and 2 whether or not the binary stretch of methylation marks on the DNA molecule comprise a language of sorts, properly constrained by thermodynamic principles. The study was performed for genome-wide methylation data from 152 ecotypes and 40 trans-generational variations of Arabidopsis thaliana and 93 human tissues. The DNA persistence length, a basic mechanical property altered by CDM, was estimated with values from 39 to 66.9 nm. Classical methylome analysis can be retrieved by applying information thermodynamic modelling, which is able to discriminate signal from noise. Our finding suggests that the CDM signal comprises a language scheme properly constrained by molecular thermodynamic principles, which is part of an epigenomic communication system that obeys the same thermodynamic

[Isolation and identification of hydrogen-oxidizing bacteria producing 1-aminocyclopropane-1-carboxylate deaminase and the determination of enzymatic activity].

Science.gov (United States)

Fu, Bo; Wang, Weiwei; Tang, Ming; Chen, Xingdu

2009-03-01

We used Medicago sativa rhizosphere in Shaanxi province of China to isolate and identify hydrogen-oxidizing bacteria that produced ACC (1-aminocyclopropane-1-carboxylate) deaminase, and then studied the mechanism why they can promote the growth of plants. Hydrogen-oxidizing bacteria were isolated by gas-cycle incubation system. We studied the morphological character, physiological characteristics, 16S rDNA sequence analysis and built the phylogenic tree. Thin layer chromatography was used to isolate the strain that produced ACC deaminase. Ninhydrin reaction was used to test the enzyme activity. In total 37 strains were isolated, 8 of which could oxidize H2 strongly and grow chemolithoautotrophically. We initially identified them as hydrogen-oxidizing bacteria. Only strain WMQ-7 produced ACC deaminase among these 8 strains. Morphological and physiological characteristics analysis showed that strain WMQ-7 was essentially consistent with Pseudomonas putida. The 16S rDNA sequence analysis (GenBank accession number EU807744) suggested that strain WMQ-7 was clustered together with Pseudomonas putida in phylogenetic tree, with the sequence identity of 99%. Based on all these results, strain WMQ-7 was identified as Pseudomonas putida. The enzyme activity of strain WMQ-7 was 0.671 U/microg. A strain producing ACC deaminase was identified and tested.

Enzymatic conformational fluctuations along the reaction coordinate of cytidine deaminase

OpenAIRE

Noonan, Ryan C.; Carter, Charles W.; Bagdassarian, Carey K.

2002-01-01

Analysis of the crystal structures for cytidine deaminase complexed with substrate analog 3-deazacytidine, transition-state analog zebularine 3,4-hydrate, and product uridine establishes significant changes in the magnitude of atomic-scale fluctuations along the (approximate) reaction coordinate of this enzyme. Differences in fluctuations between the substrate analog complex, transition-state analog complex, and product complex are monitored via changes in corresponding crystallographic tempe...

Electron Attachment to the Gas Phase DNA Bases Cytosine and Thymine

Czech Academy of Sciences Publication Activity Database

Denifl, S.; Ptasiňska, S.; Probst, M.; Hrušák, Jan; Scheier, P.; Märk, T. D.

2004-01-01

Roč. 108, č. 31 (2004), s. 6562-6569 ISSN 1089-5639 R&D Projects: GA ČR GA203/02/0737 Institutional research plan: CEZ:AV0Z4040901 Keywords : gas-phase * cytosine * thymine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.639, year: 2004

Adenosine deaminase complexing protein (ADCP): a transformation sensitive protein with potentials of a cancer marker.

Science.gov (United States)

Herbschleb-Voogt, E; Ten Kate, J; Meera Khan, P

1983-01-01

Several observations by independent investigators in the past have indicated that adenosine deaminase complexing protein (ADCP), present in considerable quantities in certain human tissues, was absent or decreased in the cancers originated from them. During the present study, electrophoretic analysis of adenosine deaminase (ADA) isozymes and radioimmunoassay for ADCP in the primary fibroblasts and the transformed as well as certain tumor derived cell lines have demonstrated that ADCP present in large quantities in the primary cells was absent or nearly absent in the transformed or tumor-derived cell lines. Though the mechanisms involved are not yet clear, the above observations indicate that ADCP has the potentials of a useful marker in the studies on transformed cells and cancer tissues.

A halotolerant Enterobacter sp. displaying ACC deaminase activity promotes rice seedling growth under salt stress.

Science.gov (United States)

Sarkar, Anumita; Ghosh, Pallab Kumar; Pramanik, Krishnendu; Mitra, Soumik; Soren, Tithi; Pandey, Sanjeev; Mondal, Monohar Hossain; Maiti, Tushar Kanti

2018-01-01

Agricultural productivity is proven to be hampered by the synthesis of reactive oxygen species (ROS) and production of stress-induced ethylene under salinity stress. One-aminocyclopropane-1-carboxylic acid (ACC) is the direct precursor of ethylene synthesized by plants. Bacteria possessing ACC deaminase activity can use ACC as a nitrogen source preventing ethylene production. Several salt-tolerant bacterial strains displaying ACC deaminase activity were isolated from rice fields, and their plant growth-promoting (PGP) properties were determined. Among them, strain P23, identified as an Enterobacter sp. based on phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry data and the 16S rDNA sequence, was selected as the best-performing isolate for several PGP traits, including phosphate solubilization, IAA production, siderophore production, HCN production, etc. Enterobacter sp. P23 was shown to promote rice seedling growth under salt stress, and this effect was correlated with a decrease in antioxidant enzymes and stress-induced ethylene. Isolation of an acdS mutant strain enabled concluding that the reduction in stress-induced ethylene content after inoculation of strain P23 was linked to ACC deaminase activity. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Anticancer effects of the engineered stem cells transduced with therapeutic genes via a selective tumor tropism caused by vascular endothelial growth factor toward HeLa cervical cancer cells.

Science.gov (United States)

Kim, Hye-Sun; Yi, Bo-Rim; Hwang, Kyung-A; Kim, Seung U; Choi, Kyung-Chul

2013-10-01

The aim of the present study was to investigate the therapeutic efficacy of genetically engineered stem cells (GESTECs) expressing bacterial cytosine deaminase (CD) and/or human interferon-beta (IFN-β) gene against HeLa cervical cancer and the migration factors of the GESTECs toward the cancer cells. Anticancer effect of GESTECs was examined in a co-culture with HeLa cells using MTT assay to measure cell viability. A transwell migration assay was performed so as to assess the migration capability of the stem cells to cervical cancer cells. Next, several chemoattractant ligands and their receptors related to a selective migration of the stem cells toward HeLa cells were determined by real-time PCR. The cell viability of HeLa cells was decreased in response to 5-fluorocytosine (5-FC), a prodrug, indicating that 5-fluorouracil (5-FU), a toxic metabolite, was converted from 5-FC by CD gene and it caused the cell death in a co-culture system. When IFN-β was additionally expressed with CD gene by these GESTECs, the anticancer activity was significantly increased. In the migration assay, the GESTECs selectively migrated to HeLa cervical cancer cells. As results of real-time PCR, chemoattractant ligands such as MCP-1, SCF, and VEGF were expressed in HeLa cells, and several receptors such as uPAR, VEGFR2, and c-kit were produced by the GESTECs. These GESTECs transduced with CD gene and IFN-β may provide a potential of a novel gene therapy for anticervical cancer treatments via their selective tumor tropism derived from VEGF and VEGFR2 expressions between HeLa cells and the GESTECs.

The AID-induced DNA damage response in chromatin

DEFF Research Database (Denmark)

Daniel, Jeremy A; Nussenzweig, André

2013-01-01

Chemical modifications to the DNA and histone protein components of chromatin can modulate gene expression and genome stability. Understanding the physiological impact of changes in chromatin structure remains an important question in biology. As one example, in order to generate antibody diversity...... with somatic hypermutation and class switch recombination, chromatin must be made accessible for activation-induced cytidine deaminase (AID)-mediated deamination of cytosines in DNA. These lesions are recognized and removed by various DNA repair pathways but, if not handled properly, can lead to formation...... of oncogenic chromosomal translocations. In this review, we focus the discussion on how chromatin-modifying activities and -binding proteins contribute to the native chromatin environment in which AID-induced DNA damage is targeted and repaired. Outstanding questions remain regarding the direct roles...

Adenosine deaminase organic effect in normal and abnormal cerebrospinal fluid

International Nuclear Information System (INIS)

Hamad, A.M.; Samarai, M.A.

2007-01-01

To study the effect of the organic substances on adenosine deaminase (ADA) activity in normal and abnormal cerebrospinal fluid (CSF). Various concentrations of 2-mercaptopurine, Ame-tycine, Adenosine analogues (Guanine, Thymine) and ATP were tested to see their effect on ADA activity in normal and abnormal CSF. ADA activity in normal and abnormal CSF was remarkably decreased with the increasing of concentrations of substances tested. These effects may have important therapeutic implications. (author)

APOBEC3 cytidine deaminases in double-strand DNA break repair and cancer promotion.

Science.gov (United States)

Nowarski, Roni; Kotler, Moshe

2013-06-15

High frequency of cytidine to thymidine conversions was identified in the genome of several types of cancer cells. In breast cancer cells, these mutations are clustered in long DNA regions associated with single-strand DNA (ssDNA), double-strand DNA breaks (DSB), and genomic rearrangements. The observed mutational pattern resembles the deamination signature of cytidine to uridine carried out by members of the APOBEC3 family of cellular deaminases. Consistently, APOBEC3B (A3B) was recently identified as the mutational source in breast cancer cells. A3G is another member of the cytidine deaminases family predominantly expressed in lymphoma cells, where it is involved in mutational DSB repair following ionizing radiation treatments. This activity provides us with a new paradigm for cancer cell survival and tumor promotion and a mechanistic link between ssDNA, DSBs, and clustered mutations. Cancer Res; 73(12); 3494-8. ©2013 AACR. ©2013 AACR.

The Effect of Acute Exercise upon Adenosin Deaminase Oxidant and Antioxidant Activity

Science.gov (United States)

Kafkas, M. Emin; Karabulut, Aysun Bay; Sahin, Armagan; Otlu, Onder; Savas, Seyfi; Aytac, Aylin

2012-01-01

The purpose of this study was to determine the changes of MDA, glutation (GSH), Adenozine deaminase (ADA) and superoxidase dismutaze (SOD) levels with exercise training in obese middle-aged women (body mass index, MMI [greater than or equal to] 30.0). Twelve obese middle-aged women participated in this study. The descriptive statistics of some of…

Autoimmune dysregulation and purine metabolism in adenosine deaminase (ADA-deficiency

Directory of Open Access Journals (Sweden)

Aisha Vanessa Sauer

2012-08-01

Full Text Available Genetic defects in the adenosine deaminase (ADA gene are among the most common causes for severe combined immunodeficiency (SCID. ADA-SCID patients suffer from lymphopenia, severely impaired cellular and humoral immunity, failure to thrive and recurrent infections. Currently available therapeutic options for this otherwise fatal disorder include bone marrow transplantation (BMT, enzyme replacement therapy with bovine ADA (PEG-ADA or hematopoietic stem cell gene therapy (HSC-GT. Although varying degrees of immune reconstitution can be achieved by these treatments, breakdown of tolerance is a major concern in ADA-SCID. Immune dysregulation such as autoimmune hypothyroidism, diabetes mellitus, hemolytic anemia, and immune thrombocytopenia are frequently observed in milder forms of the disease. However, several reports document similar complications also in patients on long-term PEG-ADA and after BMT or GT treatment.A skewed repertoire and decreased immune functions have been implicated in autoimmunity observed in certain B-cell and/or T-cell immunodeficiencies, but it remains unclear to what extent specific mechanisms of tolerance are affected in ADA deficiency. Herein we provide an overview about ADA-SCID and the autoimmune manifestations reported in these patients before and after treatment. We also assess the value of the ADA-deficient mouse model as a useful tool to study both immune and metabolic disease mechanisms. With focus on regulatory T and B cells we discuss the lymphocyte subpopulations particularly prone to contribute to the loss of self-tolerance and onset of autoimmunity in ADA deficiency. Moreover we address which aspects of immune dysregulation are specifically related to alterations in purine metabolism caused by the lack of ADA and the subsequent accumulation of metabolites with immunomodulatory properties.

A novel missense mutation of gene in a Chinese family leading to ...

Indian Academy of Sciences (India)

SHUAI-MEI LIU

2017-12-18

Dec 18, 2017 ... Identification of RNA-specific adenosine deaminase 1 (ADAR1) gene results in DSH. ... In this study, we found that a 28 year-old male patient harbouring a deleterious ... tion system contained 14.75 µL double-distilled water,.

Hydration properties of natural and synthetic DNA sequences with methylated adenine or cytosine bases in the R.DpnI target and BDNF promoter studied by molecular dynamics simulations

Science.gov (United States)

Shanak, Siba; Helms, Volkhard

2014-12-01

Adenine and cytosine methylation are two important epigenetic modifications of DNA sequences at the levels of the genome and transcriptome. To characterize the differential roles of methylating adenine or cytosine with respect to their hydration properties, we performed conventional MD simulations and free energy perturbation calculations for two particular DNA sequences, namely the brain-derived neurotrophic factor (BDNF) promoter and the R.DpnI-bound DNA that are known to undergo methylation of C5-methyl cytosine and N6-methyl adenine, respectively. We found that a single methylated cytosine has a clearly favorable hydration free energy over cytosine since the attached methyl group has a slightly polar character. In contrast, capping the strongly polar N6 of adenine with a methyl group gives a slightly unfavorable contribution to its free energy of solvation. Performing the same demethylation in the context of a DNA double-strand gave quite similar results for the more solvent-accessible cytosine but much more unfavorable results for the rather buried adenine. Interestingly, the same demethylation reactions are far more unfavorable when performed in the context of the opposite (BDNF or R.DpnI target) sequence. This suggests a natural preference for methylation in a specific sequence context. In addition, free energy calculations for demethylating adenine or cytosine in the context of B-DNA vs. Z-DNA suggest that the conformational B-Z transition of DNA transition is rather a property of cytosine methylated sequences but is not preferable for the adenine-methylated sequences investigated here.

Targeted and genome-scale methylomics reveals gene body signatures in human cell lines

Science.gov (United States)

Ball, Madeleine Price; Li, Jin Billy; Gao, Yuan; Lee, Je-Hyuk; LeProust, Emily; Park, In-Hyun; Xie, Bin; Daley, George Q.; Church, George M.

2012-01-01

Cytosine methylation, an epigenetic modification of DNA, is a target of growing interest for developing high throughput profiling technologies. Here we introduce two new, complementary techniques for cytosine methylation profiling utilizing next generation sequencing technology: bisulfite padlock probes (BSPPs) and methyl sensitive cut counting (MSCC). In the first method, we designed a set of ~10,000 BSPPs distributed over the ENCODE pilot project regions to take advantage of existing expression and chromatin immunoprecipitation data. We observed a pattern of low promoter methylation coupled with high gene body methylation in highly expressed genes. Using the second method, MSCC, we gathered genome-scale data for 1.4 million HpaII sites and confirmed that gene body methylation in highly expressed genes is a consistent phenomenon over the entire genome. Our observations highlight the usefulness of techniques which are not inherently or intentionally biased in favor of only profiling particular subsets like CpG islands or promoter regions. PMID:19329998

Formulation, quality control and shelf life of the experimental cytostatic drug cyclopentenyl cytosine

NARCIS (Netherlands)

Schimmel, Kirsten; Guchelaar, Henk-Jan; van Kan, Erik

2006-01-01

This paper describes the formulation and quality control of an aqueous sterilized formulation of the experimental cytostatic drug cyclopentenyl cytosine (CPEC) to be used in Phase I/II clinical trials. The raw drug substance was extensively tested. A High Pressure Liquid Chromotography (HPLC) method

Ecto- and cytosolic 5'-nucleotidases in normal and AMP deaminase-deficient human skeletal muscle

DEFF Research Database (Denmark)

Hanisch, Frank; Hellsten, Ylva; Zierz, Stephan

2006-01-01

homogenate 5'-nucleotidase and ectoN, or in cN-I expression on Western blots. No correlation for age, fibre type distribution and AMPD1 genotype was found for whole homogenate nucleotidase, total cN and cN-I using multiple linear regression analysis. There was no gender-specific difference in the activities...... with a homozygous C34T mutation, cN-I might be a more important pathway for AMP removal. We determined activities of AMP deaminase, cN-I, total cytosolic 5'-nucleotidase (total cN), ecto-5'-nucleotidase (ectoN) and whole homogenate 5'-nucleotidase activity in skeletal muscle biopsies from patients with different...... AMPD1 genotypes [homozygotes for C34T mutation (TT); heterozygotes for C34T mutation (CT); and homozygotes for wild type (CC): diseased controls CC; and normal controls CC]. AMP deaminase activity showed genotype-dependent differences. Total cN activity in normal controls accounted for 57...

Cytosine methylation is a conserved epigenetic feature found throughout the phylum Platyhelminthes

Science.gov (United States)

2013-01-01

Background The phylum Platyhelminthes (flatworms) contains an important group of bilaterian organisms responsible for many debilitating and chronic infectious diseases of human and animal populations inhabiting the planet today. In addition to their biomedical and veterinary relevance, some platyhelminths are also frequently used models for understanding tissue regeneration and stem cell biology. Therefore, the molecular (genetic and epigenetic) characteristics that underlie trophic specialism, pathogenicity or developmental maturation are likely to be pivotal in our continued studies of this important metazoan group. Indeed, in contrast to earlier studies that failed to detect evidence of cytosine or adenine methylation in parasitic flatworm taxa, our laboratory has recently defined a critical role for cytosine methylation in Schistosoma mansoni oviposition, egg maturation and ovarian development. Thus, in order to identify whether this epigenetic modification features in other platyhelminth species or is a novelty of S. mansoni, we conducted a study simultaneously surveying for DNA methylation machinery components and DNA methylation marks throughout the phylum using both parasitic and non-parasitic representatives. Results Firstly, using both S. mansoni DNA methyltransferase 2 (SmDNMT2) and methyl-CpG binding domain protein (SmMBD) as query sequences, we illustrate that essential DNA methylation machinery components are well conserved throughout the phylum. Secondly, using both molecular (methylation specific amplification polymorphism, MSAP) and immunological (enzyme-linked immunoabsorbent assay, ELISA) methodologies, we demonstrate that representative species (Echinococcus multilocularis, Protopolystoma xenopodis, Schistosoma haematobium, Schistosoma japonicum, Fasciola hepatica and Polycelis nigra) within all four platyhelminth classes (Cestoda, Monogenea, Trematoda and ‘Turbellaria’) contain methylated cytosines within their genome compartments

The catalase activity of diiron adenine deaminase

Energy Technology Data Exchange (ETDEWEB)

Kamat S. S.; Swaminathan S.; Holmes-Hampton, G. P.; Bagaria, A.; Kumaran, D.; Tichy, S. E.; Gheyi, T.; Zheng, X.; Bain, K.; Groshong, C.; Emtage, S.; Sauder, J. M.; Burley, S. K.; Lindahl, P. A.; Raushel, F. M.

2011-12-01

Adenine deaminase (ADE) from the amidohydrolase superfamily (AHS) of enzymes catalyzes the conversion of adenine to hypoxanthine and ammonia. Enzyme isolated from Escherichia coli was largely inactive toward the deamination of adenine. Molecular weight determinations by mass spectrometry provided evidence that multiple histidine and methionine residues were oxygenated. When iron was sequestered with a metal chelator and the growth medium supplemented with Mn{sup 2+} before induction, the post-translational modifications disappeared. Enzyme expressed and purified under these conditions was substantially more active for adenine deamination. Apo-enzyme was prepared and reconstituted with two equivalents of FeSO{sub 4}. Inductively coupled plasma mass spectrometry and Moessbauer spectroscopy demonstrated that this protein contained two high-spin ferrous ions per monomer of ADE. In addition to the adenine deaminase activity, [Fe{sup II}/Fe{sup II}]-ADE catalyzed the conversion of H{sub 2}O{sub 2} to O{sub 2} and H{sub 2}O. The values of k{sub cat} and k{sub cat}/K{sub m} for the catalase activity are 200 s{sup -1} and 2.4 x 10{sup 4} M{sup -1} s{sup -1}, respectively. [Fe{sup II}/Fe{sup II}]-ADE underwent more than 100 turnovers with H{sub 2}O{sub 2} before the enzyme was inactivated due to oxygenation of histidine residues critical for metal binding. The iron in the inactive enzyme was high-spin ferric with g{sub ave} = 4.3 EPR signal and no evidence of anti-ferromagnetic spin-coupling. A model is proposed for the disproportionation of H{sub 2}O{sub 2} by [Fe{sup II}/Fe{sup II}]-ADE that involves the cycling of the binuclear metal center between the di-ferric and di-ferrous oxidation states. Oxygenation of active site residues occurs via release of hydroxyl radicals. These findings represent the first report of redox reaction catalysis by any member of the AHS.

Cytosine Arabinoside Influx and Nucleoside Transport Sites in Acute Leukemia

OpenAIRE

Wiley, J. S.; Jones, S. P.; Sawyer, W. H.; Paterson, A. R. P.

1982-01-01

Although cytosine arabinoside (araC) can induce a remission in a majority of patients presenting with acute myeloblastic leukemia (AML), a minority fail to respond and moreover the drug has less effect in acute lymphoblastic leukemia (ALL). The carrier-mediated influx of araC into purified blasts from patients with AML, ALL, and acute undifferentiated leukemia (AUL) has been compared to that of normal lymphocytes and polymorphs. Blasts showed a larger mediated influx of araC than mature cells...

A Novel Regulator of Activation-Induced Cytidine Deaminase/APOBECs in Immunity and Cancer: Schrödinger’s CATalytic Pocket

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Mani Larijani

2017-04-01

Full Text Available Activation-induced cytidine deaminase (AID and its relative APOBEC3 cytidine deaminases boost immune response by mutating immune or viral genes. Because of their genome-mutating activities, AID/APOBECs are also drivers of tumorigenesis. Due to highly charged surfaces, extensive non-specific protein–protein/nucleic acid interactions, formation of polydisperse oligomers, and general insolubility, structure elucidation of these proteins by X-ray crystallography and NMR has been challenging. Hence, almost all available AID/APOBEC structures are of mutated and/or truncated versions. In 2015, we reported a functional structure for AID using a combined computational–biochemical approach. In so doing, we described a new regulatory mechanism that is a first for human DNA/RNA-editing enzymes. This mechanism involves dynamic closure of the catalytic pocket. Subsequent X-ray and NMR studies confirmed our discovery by showing that other APOBEC3s also close their catalytic pockets. Here, we highlight catalytic pocket closure as an emerging and important regulatory mechanism of AID/APOBEC3s. We focus on three sub-topics: first, we propose that variable pocket closure rates across AID/APOBEC3s underlie differential activity in immunity and cancer and review supporting evidence. Second, we discuss dynamic pocket closure as an ever-present internal regulator, in contrast to other proposed regulatory mechanisms that involve extrinsic binding partners. Third, we compare the merits of classical approaches of X-ray and NMR, with that of emerging computational–biochemical approaches, for structural elucidation specifically for AID/APOBEC3s.

Epigenetic variation, inheritance, and parent-of-origin effects of cytosine methylation in maize (Zea mays).

Science.gov (United States)

Lauria, Massimiliano; Piccinini, Sara; Pirona, Raul; Lund, Gertrud; Viotti, Angelo; Motto, Mario

2014-03-01

Pure epigenetic variation, or epigenetic variation that is independent of genetic context, may provide a mechanism for phenotypic variation in the absence of DNA mutations. To estimate the extent of pure epigenetic variation within and across generations and to identify the DNA regions targeted, a group of eight plants derived from a highly inbred line of maize (Zea mays) was analyzed by the methylation-sensitive amplified polymorphism (MSAP) technique. We found that cytosine methylation (mC) differences among individuals accounted for up to 7.4% of CCGG sites investigated by MSAP. Of the differentially methylated fragments (DMFs) identified in the S0 generation, ∼12% were meiotically inherited for at least six generations. We show that meiotically heritable mC variation was consistently generated for an average of 0.5% CCGG sites per generation and that it largely occurred somatically. We provide evidence that mC variation can be established and inherited in a parent-of-origin manner, given that the paternal lineage is more prone to both forward and reverse mC changes. The molecular characterization of selected DMFs revealed that the variation was largely determined by CG methylation changes that map within gene regions. The expression analysis of genes overlapping with DMFs did not reveal an obvious correlation between mC variation and transcription, reinforcing the idea that the primary function of gene-body methylation is not to control gene expression. Because this study focuses on epigenetic variation in field-grown plants, the data presented herein pertain to spontaneous epigenetic changes of the maize genome in a natural context.

Biophysical and molecular docking insight into the interaction of cytosine β-D arabinofuranoside with human serum albumin

International Nuclear Information System (INIS)

Alam, Parvez; Chaturvedi, Sumit Kumar; Anwar, Tamanna; Siddiqi, Mohammad Khursheed; Ajmal, Mohd Rehan; Badr, Gamal; Mahmoud, Mohamed H.; Hasan Khan, Rizwan

2015-01-01

Interaction of pharmacologically important anticancer drug cytosine β-D arabinofuranoside with human serum albumin (HSA) at physiological pH 7.4 has been studied by utilizing various spectroscopic and molecular docking strategies. Fluorescence results revealed that cytosine β-D arabinofuranoside interacts with HSA through static quenching mechanism with binding affinity of 2.4×10 3 M −1 . The average binding distance between drug and Trp 214 of HSA was found to be 2.23 nm on the basis of the theory of Förster's energy transfer. Synchronous fluorescence data indicated that interaction of drug with HSA changed the microenvironment around the tryptophan residue. UV–visible spectroscopy and circular dichroism results deciphered the complex formation and conformational alterations in the HSA respectively. Dynamic light scattering was utilized to understand the topology of protein in absence and presence of drug. Thermodynamic parameters obtained from isothermal titration calorimetry (ΔH=−26.01 kJ mol −1 and TΔS=6.5 kJ mol −1 ) suggested the involvement of van der Waal interaction and hydrogen bonding. Molecular docking and displacement study with site specific markers suggested that cytosine β-D arabinofuranoside binds to subdomain IB of HSA which is also known as the hemin binding site. This study will be helpful to understand the binding mechanism of cytosine β-D arabinofuranoside with HSA and associated alterations. - Highlights: • Comprehensive insight into the interaction of CBDA with HSA. • The interaction process is spontaneous and exothermic. • The main governing forces for stabilizing HSA–CBDA complex are van der Waal interaction and hydrogen bonding. • CBDA binds at subdomain IB on HSA

Involvement of a cytosine side chain in proton transfer in the rate-determining step of ribozyme self-cleavage

Science.gov (United States)

Shih, I-hung; Been, Michael D.

2001-01-01

Ribozymes of hepatitis delta virus have been proposed to use an active-site cytosine as an acid-base catalyst in the self-cleavage reaction. In this study, we have examined the role of cytosine in more detail with the antigenomic ribozyme. Evidence that proton transfer in the rate-determining step involved cytosine 76 (C76) was obtained from examining cleavage activity of the wild-type and imidazole buffer-rescued C76-deleted (C76Δ) ribozymes in D2O and H2O. In both reactions, a similar kinetic isotope effect and shift in the apparent pKa indicate that the buffer is functionally substituting for the side chain in proton transfer. Proton inventory of the wild-type reaction supported a mechanism of a single proton transfer at the transition state. This proton transfer step was further characterized by exogenous base rescue of a C76Δ mutant with cytosine and imidazole analogues. For the imidazole analogues that rescued activity, the apparent pKa of the rescue reaction, measured under kcat/KM conditions, correlated with the pKa of the base. From these data a Brønsted coefficient (β) of 0.51 was determined for the base-rescued reaction of C76Δ. This value is consistent with that expected for proton transfer in the transition state. Together, these data provide strong support for a mechanism where an RNA side chain participates directly in general acid or general base catalysis of the wild-type ribozyme to facilitate RNA cleavage. PMID:11171978

Cytosine deletion at AP2-box region of HSP70 promoter and its ...

Indian Academy of Sciences (India)

Cytosine deletion at AP2-box region of HSP70 promoter and its influence on semen quality traits in crossbred bulls ... Laboratory, ICAR-Central Institute for Research on Cattle, Meerut 250 001, India; School of Atmospheric Stress Management, ICAR-National Institute of Abiotic Stress Management, Baramati 413 115, India ...

Base damage within single-strand DNA underlies in vivo hypermutability induced by a ubiquitous environmental agent.

Directory of Open Access Journals (Sweden)

Kin Chan

Full Text Available Chromosomal DNA must be in single-strand form for important transactions such as replication, transcription, and recombination to occur. The single-strand DNA (ssDNA is more prone to damage than double-strand DNA (dsDNA, due to greater exposure of chemically reactive moieties in the nitrogenous bases. Thus, there can be agents that damage regions of ssDNA in vivo while being inert toward dsDNA. To assess the potential hazard posed by such agents, we devised an ssDNA-specific mutagenesis reporter system in budding yeast. The reporter strains bear the cdc13-1 temperature-sensitive mutation, such that shifting to 37°C results in telomere uncapping and ensuing 5' to 3' enzymatic resection. This exposes the reporter region, containing three closely-spaced reporter genes, as a long 3' ssDNA overhang. We validated the ability of the system to detect mutagenic damage within ssDNA by expressing a modified human single-strand specific cytosine deaminase, APOBEC3G. APOBEC3G induced a high density of substitutions at cytosines in the ssDNA overhang strand, resulting in frequent, simultaneous inactivation of two reporter genes. We then examined the mutagenicity of sulfites, a class of reactive sulfur oxides to which humans are exposed frequently via respiration and food intake. Sulfites, at a concentration similar to that found in some foods, induced a high density of mutations, almost always as substitutions at cytosines in the ssDNA overhang strand, resulting in simultaneous inactivation of at least two reporter genes. Furthermore, sulfites formed a long-lived adducted 2'-deoxyuracil intermediate in DNA that was resistant to excision by uracil-DNA N-glycosylase. This intermediate was bypassed by error-prone translesion DNA synthesis, frequently involving Pol ζ, during repair synthesis. Our results suggest that sulfite-induced lesions in DNA can be particularly deleterious, since cells might not possess the means to repair or bypass such lesions

Regulation of adenosine deaminase (ADA) on induced mouse experimental autoimmune uveitis (EAU) ?

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Liang, Dongchun; Zuo, Aijun; Zhao, Ronglan; Shao, Hui; Kaplan, Henry J.; Sun, Deming

2016-01-01

Adenosine is an important regulator of the immune response and adenosine deaminase (ADA) inhibits this regulatory effect by converting adenosine into functionally inactive molecules. Studies have shown that adenosine receptor (AR) agonists can be either anti- or pro-inflammatory. Clarification of the mechanisms that cause these opposing effects should provide a better guide for therapeutic intervention. In this study, we investigated the effect of ADA on the development of experimental autoim...

Crystallization and preliminary X-ray characterization of the tetrapyrrole-biosynthetic enzyme porphobilinogen deaminase from Bacillus megaterium

International Nuclear Information System (INIS)

Azim, N.; Deery, E.; Warren, M. J.; Erskine, P.; Cooper, J. B.; Wood, S. P.; Akhtar, M.

2013-01-01

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step in the biosynthesis of tetrapyrroles in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. PBGD from B. megaterium was expressed and the enzyme was crystallized in a form which diffracts synchrotron radiation to high resolution. The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor which is covalently linked by a thioether bridge to an invariant cysteine residue. Expression in Escherichia coli of a His-tagged form of Bacillus megaterium PBGD permitted the crystallization and preliminary X-ray analysis of the enzyme from this species at high resolution

Restriction of Equine Infectious Anemia Virus by Equine APOBEC3 Cytidine Deaminases ▿ †

Science.gov (United States)

Zielonka, Jörg; Bravo, Ignacio G.; Marino, Daniela; Conrad, Elea; Perković, Mario; Battenberg, Marion; Cichutek, Klaus; Münk, Carsten

2009-01-01

The mammalian APOBEC3 (A3) proteins comprise a multigene family of cytidine deaminases that act as potent inhibitors of retroviruses and retrotransposons. The A3 locus on the chromosome 28 of the horse genome contains multiple A3 genes: two copies of A3Z1, five copies of A3Z2, and a single copy of A3Z3, indicating a complex evolution of multiple gene duplications. We have cloned and analyzed for expression the different equine A3 genes and examined as well the subcellular distribution of the corresponding proteins. Additionally, we have tested the functional antiretroviral activity of the equine and of several of the human and nonprimate A3 proteins against the Equine infectious anemia virus (EIAV), the Simian immunodeficiency virus (SIV), and the Adeno-associated virus type 2 (AAV-2). Hematopoietic cells of horses express at least five different A3s: A3Z1b, A3Z2a-Z2b, A3Z2c-Z2d, A3Z2e, and A3Z3, whereas circulating macrophages, the natural target of EIAV, express only part of the A3 repertoire. The five A3Z2 tandem copies arose after three consecutive, recent duplication events in the horse lineage, after the split between Equidae and Carnivora. The duplicated genes show different antiviral activities against different viruses: equine A3Z3 and A3Z2c-Z2d are potent inhibitors of EIAV while equine A3Z1b, A3Z2a-Z2b, A3Z2e showed only weak anti-EIAV activity. Equine A3Z1b and A3Z3 restricted AAV and all equine A3s, except A3Z1b, inhibited SIV. We hypothesize that the horse A3 genes are undergoing a process of subfunctionalization in their respective viral specificities, which might provide the evolutionary advantage for keeping five copies of the original gene. PMID:19458006

Radio-chromatographic determination of plasmatic adenosine deaminase (A.D.); Determination radiochromatographique de l'adenosine deaminase (A.D.)

Energy Technology Data Exchange (ETDEWEB)

Chivot, J J; Depernet, D; Caen, J [Commissariat a l' Energie Atomique, Bruyeres-le-Chatel (France). Centre d' Etudes

1970-07-01

We were able, by using a radio-chromatographic method, to measure an adenosine deaminase activity in normal human heparinized platelet-poor plasma, which can degrade 0.016 {mu}M adenosine. This activity suppressed by heating 56 C for 30 minutes is inhibited by high concentrations of urea and is proportional to the amount of plasma, source of enzyme, in the systems. (authors) [French] Nous avons pu, en utilisant une methode radiochromatographique, mesurer une activite adenosine deaminasique dans le plasma humain pauvre en plaquettes heparine qui peut degrader 0,016 {mu}M d'adenosine. Cette activite qui est supprimee par chauffage a 56 degres pendant 30 minutes, est reduite par conservation a -20 C pendant une semaine, est inhibee par d'importantes concentrations d'uree et ne l'est pas, ni par le dipyridamol, ni par le pHMB. Cette activite est proportionnelle a la quantite de plasma, source d'enzyme, mise dans les differents systemes reactifs. (auteur)

An N-Glycosidase from Escherichia coli That Releases Free Uracil from DNA Containing Deaminated Cytosine Residues

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Lindahl, Tomas

1974-01-01

An enzyme that liberates uracil from single-stranded and double-stranded DNA containing deaminated cytosine residues and from deoxycytidylate-deoxyuridylate copolymers in the absence of Mg++ has been purified 30-fold from cell extracts of E. coli. The enzyme does not release uracil from deoxyuridine, dUMP, uridine, or RNA, nor does it liberate the normally occurring pyrimidine bases, cytosine and thymine, from DNA. The enzymatic cleavage of N-glycosidic bonds in DNA occurs without concomitant cleavage of phosphodiester bonds, resulting in the formation of free uracil and DNA strands of unaltered chain length that contain apyrimidinic sites as reaction products. The enzyme may be active in DNA repair, converting deaminated dCMP residues to an easily repairable form. PMID:4610583

Biological function of activation-induced cytidine deaminase (AID

Directory of Open Access Journals (Sweden)

Ritu Kumar

2014-10-01

Full Text Available Activation-induced Cytidine Deaminase (AID is an essential regulator of B cell diversification, but its full range of action has until recently been an enigma. Based on homology, it was originally proposed to be an RNA-editing enzyme, but so far, no RNA substrates are known. Rather, it functions by deaminating cytidine, and in this manner, coupled with base-excision repair or mismatch repair machinery, it is a natural mutator. This allows it to play a central role in adaptive immunity, whereby it initiates the processes of class switch recombination and somatic hypermutation to help generate a diverse and high-affinity repertoire of immunoglobulin isotypes. More recently, it has been appreciated that methylated cytidine, already known as a key epigenetic mark on DNA controlling gene expression, can also be a target for AID modification. Coupled with repair machinery, this can facilitate the active removal of methylated DNA. This activity can impact the process of cellular reprogramming, including transition of a somatic cell to pluripotency, which requires major reshuffling of epigenetic memory. Thus, seemingly disparate roles for AID in controlling immune diversity and epigenetic memory have a common mechanistic basis. However, the very activity that is so useful for B cell diversity and cellular reprogramming is dangerous for the integrity of the genome. Thus, AID expression and activity is tightly regulated, and deregulation is associated with diseases including cancer. Here, we review the range of AID functions with a focus on its mechanisms of action and regulation. Major questions remain to be answered concerning how and when AID is targeted to specific loci and how this impacts development and disease.

Biophysical and molecular docking insight into the interaction of cytosine β-D arabinofuranoside with human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Alam, Parvez; Chaturvedi, Sumit Kumar [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India); Anwar, Tamanna [Center of Bioinformatics Research and Technology, Aligarh 202002 (India); Siddiqi, Mohammad Khursheed; Ajmal, Mohd Rehan [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India); Badr, Gamal [Laboratory of Immunology & Molecular Physiology, Zoology Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Mahmoud, Mohamed H. [Food Science and Nutrition Department, National Research Center, Dokki, Cairo (Egypt); Deanship of Scientific Research, King Saud University, Riyadh (Saudi Arabia); Hasan Khan, Rizwan, E-mail: rizwanhkhan@hotmail.com [Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, UP (India)

2015-08-15

Interaction of pharmacologically important anticancer drug cytosine β-D arabinofuranoside with human serum albumin (HSA) at physiological pH 7.4 has been studied by utilizing various spectroscopic and molecular docking strategies. Fluorescence results revealed that cytosine β-D arabinofuranoside interacts with HSA through static quenching mechanism with binding affinity of 2.4×10{sup 3} M{sup −1}. The average binding distance between drug and Trp{sup 214} of HSA was found to be 2.23 nm on the basis of the theory of Förster's energy transfer. Synchronous fluorescence data indicated that interaction of drug with HSA changed the microenvironment around the tryptophan residue. UV–visible spectroscopy and circular dichroism results deciphered the complex formation and conformational alterations in the HSA respectively. Dynamic light scattering was utilized to understand the topology of protein in absence and presence of drug. Thermodynamic parameters obtained from isothermal titration calorimetry (ΔH=−26.01 kJ mol{sup −1} and TΔS=6.5 kJ mol{sup −1}) suggested the involvement of van der Waal interaction and hydrogen bonding. Molecular docking and displacement study with site specific markers suggested that cytosine β-D arabinofuranoside binds to subdomain IB of HSA which is also known as the hemin binding site. This study will be helpful to understand the binding mechanism of cytosine β-D arabinofuranoside with HSA and associated alterations. - Highlights: • Comprehensive insight into the interaction of CBDA with HSA. • The interaction process is spontaneous and exothermic. • The main governing forces for stabilizing HSA–CBDA complex are van der Waal interaction and hydrogen bonding. • CBDA binds at subdomain IB on HSA.

Pleural Fluid Adenosine Deaminase (ADA) Predicts Survival in Patients with Malignant Pleural Effusion.

Science.gov (United States)

Terra, Ricardo Mingarini; Antonangelo, Leila; Mariani, Alessandro Wasum; de Oliveira, Ricardo Lopes Moraes; Teixeira, Lisete Ribeiro; Pego-Fernandes, Paulo Manuel

2016-08-01

Systemic and local inflammations have been described as relevant prognostic factors in patients with cancer. However, parameters that stand for immune activity in the pleural space have not been tested as predictors of survival in patients with malignant pleural effusion. The objective of this study was to evaluate pleural lymphocytes and Adenosine Deaminase (ADA) as predictors of survival in patients with recurrent malignant pleural effusion. Retrospective cohort study includes patients who underwent pleurodesis for malignant pleural effusion in a tertiary center. Pleural fluid protein concentration, lactate dehydrogenase, glucose, oncotic cytology, cell count, and ADA were collected before pleurodesis and analyzed. Survival analysis was performed considering pleurodesis as time origin, and death as the event. Backwards stepwise Cox regression was used to find predictors of survival. 156 patients (out of 196 potentially eligible) were included in this study. Most were female (72 %) and breast cancer was the most common underlying malignancy (53 %). Pleural fluid ADA level was stratified as low (Pleural fluid cell count and lymphocytes number and percentage did not correlate with survival. Pleural fluid Adenosine Deaminase levels (pleural effusion who undergo pleurodesis.

Elastic electron scattering from the DNA bases cytosine and thymine

International Nuclear Information System (INIS)

Colyer, C. J.; Bellm, S. M.; Lohmann, B.; Blanco, F.; Garcia, G.

2011-01-01

Cross-section data for electron scattering from biologically relevant molecules are important for the modeling of energy deposition in living tissue. Relative elastic differential cross sections have been measured for cytosine and thymine using the crossed-beam method. These measurements have been performed for six discrete electron energies between 60 and 500 eV and for detection angles between 15 deg. and 130 deg. Calculations have been performed via the screen-corrected additivity rule method and are in good agreement with the present experiment.

Electron attachment to the guanine-cytosine nucleic acid base pair and the effects of monohydration and proton transfer.

Science.gov (United States)

Gupta, Ashutosh; Jaeger, Heather M; Compaan, Katherine R; Schaefer, Henry F

2012-05-17

The guanine-cytosine (GC) radical anion and its interaction with a single water molecule is studied using ab initio and density functional methods. Z-averaged second-order perturbation theory (ZAPT2) was applied to GC radical anion for the first time. Predicted spin densities show that the radical character is localized on cytosine. The Watson-Crick monohydrated GC anion is compared to neutral GC·H2O, as well as to the proton-transferred analogue on the basis of structural and energetic properties. In all three systems, local minima are identified that correspond to water positioned in the major and minor grooves of macromolecular DNA. On the anionic surface, two novel structures have water positioned above or below the GC plane. On the neutral and anionic surfaces, the global minimum can be described as water interacting with the minor groove. These structures are predicted to have hydration energies of 9.7 and 11.8 kcal mol(-1), respectively. Upon interbase proton-transfer (PT), the anionic global minimum has water positioned in the major groove, and the hydration energy increases to 13.4 kcal mol(-1). PT GC·H2O(•-) has distonic character; the radical character resides on cytosine, while the negative charge is localized on guanine. The effects of proton transfer are further investigated through the computed adiabatic electron affinities (AEA) of GC and monohydrated GC, and the vertical detachment energies (VDE) of the corresponding anions. Monohydration increases the AEAs and VDEs by only 0.1 eV, while proton-transfer increases the VDEs substantially (0.8 eV). The molecular charge distribution of monohydrated guanine-cytosine radical anion depends heavily on interbase proton transfer.

Diversification of the Primary Antibody Repertoire by AID-Mediated Gene Conversion.

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Lanning, Dennis K; Knight, Katherine L

2015-01-01

Gene conversion, mediated by activation-induced cytidine deaminase (AID), has been found to contribute to generation of the primary antibody repertoire in several vertebrate species. Generation of the primary antibody repertoire by gene conversion of immunoglobulin (Ig) genes occurs primarily in gut-associated lymphoid tissues (GALT) and is best described in chicken and rabbit. Here, we discuss current knowledge of the mechanism of gene conversion as well as the contribution of the microbiota in promoting gene conversion of Ig genes. Finally, we propose that the antibody diversification strategy used in GALT species, such as chicken and rabbit, is conserved in a subset of human and mouse B cells.

Mutations in the human adenosine deaminase gene that affect protein structure and RNA splicing

International Nuclear Information System (INIS)

Akeson, A.L.; Wiginton, D.A.; States, C.J.; Perme, C.M.; Dusing, M.R.; Hutton, J.J.

1987-01-01

Adenosine deaminase deficiency is one cause of the genetic disease severe combined immunodeficiency. To identify mutations responsible for ADA deficiency, the authors synthesized cDNAs to ADA mRNAs from two cell lines, GM2756 and GM2825A, derived from ADA-deficient immunodeficient patients. Sequence analysis of GM2756 cDNA clones revealed a different point mutation in each allele that causes amino acid changes of alanine to valine and arginine to histidine. One allele of GM2825A also has a point mutation that causes an alanine to valine substitution. The other allele of GM2825A was found to produce an mRNA in which exon 4 had been spliced out but had no other detrimental mutations. S1 nuclease mapping of GM2825A mRNA showed equal abundance of the full-length ADA mRNA and the ADA mRNA that was missing exon 4. Several of the ADA cDNA clones extended 5' of the major initiation start site, indicating multiple start sites for ADA transcription. The point mutations in GM2756 and GM2825A and the absence of exon 4 in GM2825A appear to be directly responsible for the ADA deficiency. Comparison of a number of normal and mutant ADA cDNA sequences showed a number of changes in the third base of codons. These change do not affect the amino acid sequence. Analyses of ADA cDNAs from different cell lines detected aberrant RNA species that either included intron 7 or excluded exon 7. Their presence is a result of aberrant splicing of pre-mRNAs and is not related to mutations that cause ADA deficiency

Restoration of adenosine deaminase-deficient human thymocyte development in vitro by inhibition of deoxynucleoside kinases.

Science.gov (United States)

Joachims, Michelle L; Marble, Patrick A; Laurent, Aletha B; Pastuszko, Peter; Paliotta, Marco; Blackburn, Michael R; Thompson, Linda F

2008-12-01

Mutations in the gene encoding adenosine deaminase (ADA), a purine salvage enzyme, lead to immunodeficiency in humans. Although ADA deficiency has been analyzed in cell culture and murine models, information is lacking concerning its impact on the development of human thymocytes. We have used chimeric human/mouse fetal thymic organ culture to study ADA-deficient human thymocyte development in an "in vivo-like" environment where toxic metabolites accumulate in situ. Inhibition of ADA during human thymocyte development resulted in a severe reduction in cellular expansion as well as impaired differentiation, largely affecting mature thymocyte populations. Thymocyte differentiation was not blocked at a discrete stage; rather, the paucity of mature thymocytes was due to the induction of apoptosis as evidenced by activation of caspases and was accompanied by the accumulation of intracellular dATP. Inhibition of adenosine kinase and deoxycytidine kinase prevented the accumulation of dATP and restored thymocyte differentiation and proliferation. Our work reveals that multiple deoxynucleoside kinases are involved in the phosphorylation of deoxyadenosine when ADA is absent, and suggests an alternate therapeutic strategy for treatment of ADA-deficient patients.

Huntingtin gene repeat size variations affect risk of lifetime depression

DEFF Research Database (Denmark)

Gardiner, Sarah L.; van Belzen, Martine J.; Boogaard, Merel W.

2017-01-01

Huntington disease (HD) is a severe neuropsychiatric disorder caused by a cytosine-adenine-guanine (CAG) repeat expansion in the HTT gene. Although HD is frequently complicated by depression, it is still unknown to what extent common HTT CAG repeat size variations in the normal range could affect...

Diagnostic Value of Serum Adenosine Deaminase (ADA) Level for Pulmonary Tuberculosis.

Science.gov (United States)

Salmanzadeh, Shokrollah; Tavakkol, Heshmatollah; Bavieh, Khalid; Alavi, Seyed Mohammad

2015-03-01

Diagnosis of tuberculosis (TB) is not always easy, thus employing methods with a short duration and acceptable sensitivity and specificity is necessary to diagnose TB. The aim of this study was to investigate the diagnostic value of serum adenosine deaminase (ADA) level for diagnosis of pulmonary tuberculosis. A total of 160 sex and age-matched subjects were included in this study, and were divided to four groups; forty patients with pulmonary tuberculosis (PTB) diagnosed based on the national TB program (NTP), forty patients with non-tuberculosis bacterial pneumonia, forty patients with lung cancer and forty people who were healthy in every respect. Serum adenosine deaminase activity in patients of each group was measured by the Giusti and Galanti calorimetry method using a commercial kit (Diazyme, USA). The ANOVA analysis was used to compare groups for quantitative variables. Mean serum ADA level in the PTB group was clearly higher than the mean serum ADA in the other three groups. Mean serum ADA was 26 IU/L in PTB patients, 19.48 IU/L in patients with pneumonia, 15.8 IU/L in patients with lung cancer, and 10.7 IU/L in the control group (P ADA in patients with PTB sensitivity and specificity was defined as 35% and 91%, respectively. Serum ADA activity with high specificity percentage may be a useful alternative test in restricted resource areas to rule out diagnosis of PTB. However, serum ADA activity is not a useful tool for TB diagnosis.

Nanoswitches based on DNA base pairs: why adenine-thymine is less suitable than guanine-cytosine

NARCIS (Netherlands)

Fonseca Guerra, C.; van der Wijst, T.; Bickelhaupt, F.M.

2006-01-01

Substituted Watson-Crick guanine-cytosine (GC) base pairs were recently shown to yield robust three-state nanoswitches. Here, we address the question: Can such supramolecular switches also be based on Watson-Crick adenine-thymine (AT) base pairs? We have theoretically analyzed AT pairs in which

Epigenetic editing using programmable zinc ginger proteins : inherited silencing of endogenous gene expression by targeted DNA methylation

NARCIS (Netherlands)

Stolzenburg, Sabine

2014-01-01

Cancer development is not only the result of genetic mutations but also stems from modifications in the epigenetic code leading to an aberrant expression of genes relevant for cancer. The most studied epigenetic mark is DNA methylation of cytosines in the promoters of genes, which is associated with

Threonine deaminase from extremely halophilic bacteria - Cooperative substrate kinetics and salt dependence.

Science.gov (United States)

Lieberman, M. M.; Lanyi, J. K.

1972-01-01

The effect of salt on the activity, stability, and allosteric properties of catabolic threonine deaminase from Halobacterium cutirubrum was studied. The enzyme exhibits sigmoidal kinetics with the substrate, threonine. The Hill slope is 1.55 at pH 10. The enzyme is activated by ADP at low substrate concentrations. In the presence of this effector, sigmoidal kinetics are no longer observed. At pH 10, in the absence of ADP, enzyme activity increases with increasing NaCl concentration from 0 to 4 M.

Cyclopentenyl cytosine induces apoptosis and increases cytarabine-induced apoptosis in a T-lymphoblastic leukemic cell-line

NARCIS (Netherlands)

Verschuur, A. C.; Brinkman, J.; van Gennip, A. H.; Leen, R.; Vet, R. J.; Evers, L. M.; Voûte, P. A.; van Kuilenburg, A. B.

2001-01-01

Cyclopentenyl cytosine (CPEC) is a nucleoside-analogue that decreases the concentrations of cytidine triphosphate (CTP) and deoxycytidine triphosphate (dCTP) in leukemic cells by inhibiting the enzyme CTP synthetase, resulting in a decreased synthesis of RNA and DNA. Low concentrations of dCTP

Hypermethylation of E-Cadherin and Estrogen Receptor-a Gene Promoter and Its Association with Clinicopathological Features of Breast Cancer in Iranian Patients

Directory of Open Access Journals (Sweden)

Mozhgan Rasti

2009-06-01

Full Text Available Background: Aberrant methylation of cytosine-guanine dinucleotideislands leads to inactivation of tumor suppressorgenes in breast cancer. Tumor suppressor genes are unmethylatedin normal tissue and often become hypermethylatedduring tumor formation, leading to gene silencing. We investigatedthe association between E-cadherin (CDH1 and estrogenreceptor-α (ESRα gene promoter methylation andmajor clinical and pathological features of breast cancer inIranian women.Methods: DNA was extracted from 67 primary breast tumorsand gene promoter methylation was analyzed by methylationspecificpolymerase chain reaction method.Results: Fifty percent of the samples showed aberrant methylationin at least one of the two tested loci. We detectedCDH1 hypermethylation in 41% of invasive tumors and receptor-α gene hypermethylation in 18% of invasive tumorsamples. We found no association between CDH1 and receptor-α gene hypermethylation (P=0.45. There was a correlationbetween hypermethylation of CDH1 locus and tumorsize ≥5 cm (P=0.019.Conclusion: Our data suggest that the malignant progressionof human ductal and lobular breast carcinoma in Iranianwomen involves a heterogeneous pattern of cytosine-guaninedinucleotide island hypermethylation of the CDH1 gene.

Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase from Streptococcus pyogenes

Energy Technology Data Exchange (ETDEWEB)

Ku, Min-Je [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Won-Ho [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Biotechnology and Genetic Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Nam, Ki-hyun; Rhee, Kyeong-hee [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Ki-Seog [Biotechnology and Genetic Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Kim, Eunice EunKyung [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Yu, Myung-Hee [Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Hwang, Kwang Yeon, E-mail: hwangky@kist.re.kr [Biomedical Research Center, Life Science Division, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Functional Proteomics Center, Korea Institute of Science and Technology, 39-1 Hawolgok-dong, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

2005-04-01

The tRNA-specific adenosine deaminase from the pathogenic bacteria S. pyogenes has been overexpressed and crystallized. The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn{sup 2+} ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 Å using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 Å using synchrotron radiation. The crystal belongs to the tetragonal space group P4{sub 2}2{sub 1}2, with unit-cell parameters a = b = 81.042, c = 81.270 Å. The asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (V{sub M}) of 3.3 Å{sup 3} Da{sup −1} and a solvent content of 62.7%.

Simultaneous determination of cytosine arabinoside, daunorubicin and etoposide in human plasma

DEFF Research Database (Denmark)

Krogh-Madsen, Mikkel; Hansen, Steen Honoré; Honoré, Per Hartvig

2010-01-01

A method for simultaneous bioanalysis of the three cytotoxic drugs cytosine arabinoside, daunorubicin and etoposide in human plasma was developed and validated. A HPLC method with ultra-violet and fluorescence detection, preceded by mixed-mode cation-exchange solid phase extraction sample....... The overall precision (% relative standard deviation) was within 0.2-13.5% and the recovery ranged between 86.1% and 110.1% for the three drugs at all concentrations tested. Plasma samples were stable for at least two months when stored at -20 degrees C. The method was successfully applied to quantification...

Update on gene therapy of inherited immune deficiencies.

Science.gov (United States)

Engel, Barbara C; Kohn, Donald B; Podsakoff, Greg M

2003-10-01

Gene therapy has been under development as a way to correct inborn errors for many years. Recently, patients with two forms of inherited severe combined immunodeficiency (SCID), adenosine deaminase and X-linked, treated by three different clinical investigative teams, have shown significant immune reconstitution leading to protective immunity. These advances irrefutably prove the concept that hematopoietic progenitor cell gene therapy can ameliorate these diseases. However, due to proviral insertional oncogenesis, two individuals in one of the X-SCID studies developed T-cell leukemia more than two years after the gene transfer. Depending upon the results of long-term follow-up, the successes together with the side effects highlight the relative merits of this therapeutic approach.

Utility of adenosine deaminase (ADA), PCR & thoracoscopy in differentiating tuberculous & non-tuberculous pleural effusion complicating chronic kidney disease.

Science.gov (United States)

Kumar, Sravan; Agarwal, Ritesh; Bal, Amanjit; Sharma, Kusum; Singh, Navneet; Aggarwal, Ashutosh N; Verma, Indu; Rana, Satyawati V; Jha, Vivekanand

2015-03-01

Pleural effusion is a common occurrence in patients with late-stage chronic kidney disease (CKD). In developing countries, many effusions remain undiagnosed after pleural fluid analysis (PFA) and patients are empirically treated with antitubercular therapy. The aim of this study was to evaluate the role of adenosine deaminase (ADA), nucleic acid amplification tests (NAAT) and medical thoracoscopy in distinguishing tubercular and non-tubercular aetiologies in exudative pleural effusions complicating CKD. Consecutive stage 4 and 5 CKD patients with pleural effusions underwent PFA including ADA and PCR [65 kDa gene; multiplex (IS6110, protein antigen b, MPB64)]. Patients with exudative pleural effusion undiagnosed after PFA underwent medical thoracoscopy. All 107 patients underwent thoracocentesis with 45 and 62 patients diagnosed as transudative and exudative pleural effusions, respectively. Twenty six of the 62 patients underwent medical thoracoscopy. Tuberculous pleurisy was diagnosed in six while uraemic pleuritis was diagnosed in 20 subjects. The sensitivity and specificity of pleural fluid ADA, 65 kDa gene PCR, and multiplex PCR were 66.7 and 90 per cent, 100 and 50 per cent, and 100 and 100 per cent, respectively. Thoracoscopy was associated with five complications in three patients. Uraemia remains the most common cause of pleural effusion in CKD even in high TB prevalence country. Multiplex PCR and thoracoscopy are useful investigations in the diagnostic work-up of pleural effusions complicating CKD while the sensitivity and/or specificity of ADA and 65 kDa gene PCR is poor.

Characterization of 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase-Containing Pseudomonas spp. in the Rhizosphere of Salt-Stressed Canola

NARCIS (Netherlands)

Akhgar, A.; Arzanlou, M.; Bakker, Peter; Hamidpour, M.

2014-01-01

When exposed to biotic or abiotic stress conditions, plants produce ethylene from its immediate precursor 1-aminocyclopropane-1- carboxylate (ACC), leading to retarded root growth and senescence. Many plant growth-promoting rhizobacteria contain the enzyme ACC deaminase and this enzyme can cleave

Analysis of DNA Cytosine Methylation Patterns Using Methylation-Sensitive Amplification Polymorphism (MSAP).

Science.gov (United States)

Guevara, María Ángeles; de María, Nuria; Sáez-Laguna, Enrique; Vélez, María Dolores; Cervera, María Teresa; Cabezas, José Antonio

2017-01-01

Different molecular techniques have been developed to study either the global level of methylated cytosines or methylation at specific gene sequences. One of them is the methylation-sensitive amplified polymorphism technique (MSAP) which is a modification of amplified fragment length polymorphism (AFLP). It has been used to study methylation of anonymous CCGG sequences in different fungi, plants, and animal species. The main variation of this technique resides on the use of isoschizomers with different methylation sensitivity (such as HpaII and MspI) as a frequent-cutter restriction enzyme. For each sample, MSAP analysis is performed using both EcoRI/HpaII- and EcoRI/MspI-digested samples. A comparative analysis between EcoRI/HpaII and EcoRI/MspI fragment patterns allows the identification of two types of polymorphisms: (1) methylation-insensitive polymorphisms that show common EcoRI/HpaII and EcoRI/MspI patterns but are detected as polymorphic amplified fragments among samples and (2) methylation-sensitive polymorphisms which are associated with the amplified fragments that differ in their presence or absence or in their intensity between EcoRI/HpaII and EcoRI/MspI patterns. This chapter describes a detailed protocol of this technique and discusses the modifications that can be applied to adjust the technology to different species of interest.

[The influence of fasting, of a hyperprotein diet and of nicotinamide on hepatic L-threonine deaminase].

Science.gov (United States)

Aleo, M F; Casella, A; Marinello, E

1981-09-15

The induction of L-threonine deaminase, following nicotinamide injection has been studied: the effect of fasting and of hyperproteic diet have been also taken in consideration. Maximal induction is observed after 5 days hyperproteic diet, and is additional only with nicotinamide treatment. Results are interpreted assuming a different hepatic content and behavior of multiple forms of the enzyme.

Mutations in Cytosine-5 tRNA Methyltransferases Impact Mobile Element Expression and Genome Stability at Specific DNA Repeats

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Bianca Genenncher

2018-02-01

Full Text Available The maintenance of eukaryotic genome stability is ensured by the interplay of transcriptional as well as post-transcriptional mechanisms that control recombination of repeat regions and the expression and mobility of transposable elements. We report here that mutations in two (cytosine-5 RNA methyltransferases, Dnmt2 and NSun2, impact the accumulation of mobile element-derived sequences and DNA repeat integrity in Drosophila. Loss of Dnmt2 function caused moderate effects under standard conditions, while heat shock exacerbated these effects. In contrast, NSun2 function affected mobile element expression and genome integrity in a heat shock-independent fashion. Reduced tRNA stability in both RCMT mutants indicated that tRNA-dependent processes affected mobile element expression and DNA repeat stability. Importantly, further experiments indicated that complex formation with RNA could also contribute to the impact of RCMT function on gene expression control. These results thus uncover a link between tRNA modification enzymes, the expression of repeat DNA, and genomic integrity.

Planarizing cytosine: The S1 state structure, vibrations, and nonradiative dynamics of jet-cooled 5,6-trimethylenecytosine

Science.gov (United States)

Trachsel, Maria A.; Lobsiger, Simon; Schär, Tobias; Blancafort, Lluís; Leutwyler, Samuel

2017-06-01

We measure the S0 → S1 spectrum and time-resolved S1 state nonradiative dynamics of the "clamped" cytosine derivative 5,6-trimethylenecytosine (TMCyt) in a supersonic jet, using two-color resonant two-photon ionization (R2PI), UV/UV holeburning, and ns time-resolved pump/delayed ionization. The experiments are complemented with spin-component scaled second-order approximate coupled cluster (SCS-CC2), time-dependent density functional theory, and multi-state second-order perturbation-theory (MS-CASPT2) ab initio calculations. While the R2PI spectrum of cytosine breaks off ˜500 cm-1 above its 000 band, that of TMCyt extends up to +4400 cm-1 higher, with over a hundred resolved vibronic bands. Thus, clamping the cytosine C5-C6 bond allows us to explore the S1 state vibrations and S0 → S1 geometry changes in detail. The TMCyt S1 state out-of-plane vibrations ν1', ν3', and ν5' lie below 420 cm-1, and the in-plane ν11', ν12', and ν23' vibrational fundamentals appear at 450, 470, and 944 cm-1. S0 → S1 vibronic simulations based on SCS-CC2 calculations agree well with experiment if the calculated ν1', ν3', and ν5' frequencies are reduced by a factor of 2-3. MS-CASPT2 calculations predict that the ethylene-type S1 ⇝ S0 conical intersection (CI) increases from +366 cm-1 in cytosine to >6000 cm-1 in TMCyt, explaining the long lifetime and extended S0 → S1 spectrum. The lowest-energy S1 ⇝ S0 CI of TMCyt is the "amino out-of-plane" (OPX) intersection, calculated at +4190 cm-1. The experimental S1 ⇝ S0 internal conversion rate constant at the S1(v'=0 ) level is kI C=0.98 -2.2 ṡ1 08 s-1, which is ˜10 times smaller than in 1-methylcytosine and cytosine. The S1(v'=0 ) level relaxes into the T1(3π π *) state by intersystem crossing with kI S C=0.41 -1.6 ṡ1 08 s-1. The T1 state energy is measured to lie 24 580 ±560 cm-1 above the S0 state. The S1(v'=0 ) lifetime is τ =2.9 ns, resulting in an estimated fluorescence quantum yield of Φf l=24 %. Intense

First Occurrence of Plasmablastic Lymphoma in Adenosine Deaminase-Deficient Severe Combined Immunodeficiency Disease Patient and Review of the Literature

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Maddalena Migliavacca

2018-02-01

Full Text Available Adenosine deaminase-deficient severe combined immunodeficiency disease (ADA-SCID is a primary immune deficiency characterized by mutations in the ADA gene resulting in accumulation of toxic compounds affecting multiple districts. Hematopoietic stem cell transplantation (HSCT from a matched donor and hematopoietic stem cell gene therapy are the preferred options for definitive treatment. Enzyme replacement therapy (ERT is used to manage the disease in the short term, while a decreased efficacy is reported in the medium-long term. To date, eight cases of lymphomas have been described in ADA-SCID patients. Here we report the first case of plasmablastic lymphoma occurring in a young adult with ADA-SCID on long-term ERT, which turned out to be Epstein–Barr virus associated. The patient previously received infusions of genetically modified T cells. A cumulative analysis of the eight published cases of lymphoma from 1992 to date, and the case here described, reveals a high mortality (89%. The most common form is diffuse large B-cell lymphoma, which predominantly occurs in extra nodal sites. Seven cases occurred in patients on ERT and two after haploidentical HSCT. The significant incidence of immunodeficiency-associated lymphoproliferative disorders and poor survival of patients developing this complication highlight the priority in finding a prompt curative treatment for ADA-SCID.

Long-term expression of human adenosine deaminase in mice transplanted with retrovirus-infected hematopoietic stem cells

International Nuclear Information System (INIS)

Lim, B.; Apperley, J.F.; Orkin, S.H.; Williams, D.A.

1989-01-01

Long-term stable expression of foreign genetic sequences transferred into hematopoietic stem cells by using retroviral vectors constitutes a relevant model for somatic gene therapy. Such stability of expression may depend on vector design, including the presence or absence of specific sequences within the vector, in combination with the nature and efficiency of infection of the hematopoietic target cells. The authors have previously reported successful transfer of human DNA encoding adenosine deaminase (ADA) into CFU-S (colony-forming unit-spleen) stem cells using simplified recombinant retroviral vectors. Human ADA was expressed in CFU-S-derived spleen colonies at levels near to endogenous enzyme. However, because of the lack of an efficient dominant selectable marker and low recombinant viral titers, stability of long-term expression of human ADA was not examined. They report here the development of an efficient method of infection of hematopoietic stem cells (HSC) without reliance on in vitro selection. Peripheral blood samples of 100% of mice transplanted with HSC infected by this protocol exhibit expression of human ADA 30 days after transplantation. Some mice (6 of 13) continue to express human ADA in all lineages after complete hematopoietic reconstitution (4 months). The use of recombinant retroviral vectors that efficiently transfer human ADA cDNA into HSC leading to stable expression of functional ADA in reconstituted mice, provides an experimental framework for future development of approaches to somatic gene therapy

Activation-induced cytidine deaminase (AID)-dependent somatic hypermutation requires a splice isoform of the serine/arginine-rich (SR) protein SRSF1.

Science.gov (United States)

Kanehiro, Yuichi; Todo, Kagefumi; Negishi, Misaki; Fukuoka, Junji; Gan, Wenjian; Hikasa, Takuya; Kaga, Yoshiaki; Takemoto, Masayuki; Magari, Masaki; Li, Xialu; Manley, James L; Ohmori, Hitoshi; Kanayama, Naoki

2012-01-24

Somatic hypermutation (SHM) of Ig variable region (IgV) genes requires both IgV transcription and the enzyme activation-induced cytidine deaminase (AID). Identification of a cofactor responsible for the fact that IgV genes are much more sensitive to AID-induced mutagenesis than other genes is a key question in immunology. Here, we describe an essential role for a splice isoform of the prototypical serine/arginine-rich (SR) protein SRSF1, termed SRSF1-3, in AID-induced SHM in a DT40 chicken B-cell line. Unexpectedly, we found that SHM does not occur in a DT40 line lacking SRSF1-3 (DT40-ASF), although it is readily detectable in parental DT40 cells. Strikingly, overexpression of AID in DT40-ASF cells led to a large increase in nonspecific (off-target) mutations. In contrast, introduction of SRSF1-3, but not SRSF1, into these cells specifically restored SHM without increasing off-target mutations. Furthermore, we found that SRSF1-3 binds preferentially to the IgV gene and inhibits processing of the Ig transcript, providing a mechanism by which SRSF1-3 makes the IgV gene available for AID-dependent SHM. SRSF1 not only acts as an essential splicing factor but also regulates diverse aspects of mRNA metabolism and maintains genome stability. Our findings, thus, define an unexpected and important role for SRSF1, particularly for its splice variant, in enabling AID to function specifically on its natural substrate during SHM.

Asymmetric Modification of Hepatitis B Virus (HBV) Genomes by an Endogenous Cytidine Deaminase inside HBV Cores Informs a Model of Reverse Transcription.

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Nair, Smita; Zlotnick, Adam

2018-05-15

Cytidine deaminases inhibit replication of a broad range of DNA viruses by deaminating cytidines on single-stranded DNA (ssDNA) to generate uracil. While several lines of evidence have revealed hepatitis B virus (HBV) genome editing by deamination, it is still unclear which nucleic acid intermediate of HBV is modified. Hepatitis B virus has a relaxed circular double-stranded DNA (rcDNA) genome that is reverse transcribed within virus cores from a RNA template. The HBV genome also persists as covalently closed circular DNA (cccDNA) in the nucleus of an infected cell. In the present study, we found that in HBV-producing HepAD38 and HepG2.2.15 cell lines, endogenous cytidine deaminases edited 10 to 25% of HBV rcDNA genomes, asymmetrically with almost all mutations on the 5' half of the minus strand. This region corresponds to the last half of the minus strand to be protected by plus-strand synthesis. Within this half of the genome, the number of mutations peaks in the middle. Overexpressed APOBEC3A and APOBEC3G could be packaged in HBV capsids but did not change the amount or distribution of mutations. We found no deamination on pregenomic RNA (pgRNA), indicating that an intact genome is encapsidated and deaminated during or after reverse transcription. The deamination pattern suggests a model of rcDNA synthesis in which pgRNA and then newly synthesized minus-sense single-stranded DNA are protected from deaminase by interaction with the virus capsid; during plus-strand synthesis, when enough dsDNA has been synthesized to displace the remaining minus strand from the capsid surface, the single-stranded DNA becomes deaminase sensitive. IMPORTANCE Host-induced mutation of the HBV genome by APOBEC proteins may be a path to clearing the virus. We examined cytidine-to-thymidine mutations in the genomes of HBV particles grown in the presence or absence of overexpressed APOBEC proteins. We found that genomes were subjected to deamination activity during reverse transcription

Epigenetic contribution to successful polyploidizations: variation in global cytosine methylation along an extensive ploidy series in Dianthus broteri (Caryophyllaceae).

Science.gov (United States)

Alonso, Conchita; Balao, Francisco; Bazaga, Pilar; Pérez, Ricardo

2016-11-01

Polyploidization is a significant evolutionary force in plants which involves major genomic and genetic changes, frequently regulated by epigenetic factors. We explored whether natural polyploidization in Dianthus broteri complex resulted in substantial changes in global DNA cytosine methylation associated to ploidy. Global cytosine methylation was estimated by high-performance liquid chromatography (HPLC) in 12 monocytotypic populations with different ploidies (2×, 4×, 6×, 12×) broadly distributed within D. broteri distribution range. The effects of ploidy level and local variation on methylation were assessed by generalized linear mixed models (GLMMs). Dianthus broteri exhibited a higher methylation percent (˜33%) than expected by its monoploid genome size and a large variation among study populations (range: 29.3-35.3%). Global methylation tended to increase with ploidy but did not significantly differ across levels due to increased variation within the highest-order polyploidy categories. Methylation varied more among hexaploid and dodecaploid populations, despite such cytotypes showing more restricted geographic location and increased genetic relatedness than diploids and tetraploids. In this study, we demonstrate the usefulness of an HPLC method in providing precise and genome reference-free global measure of DNA cytosine methylation, suitable to advance current knowledge of the roles of this epigenetic mechanism in polyploidization processes. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Two-dimensional condensation of nucleobases: A comparative study of halogen derivatives of cytosine

Czech Academy of Sciences Publication Activity Database

Fojt, Lukáš; Vetterl, Vladimír; Doneux, T.

2009-01-01

Roč. 74, 11-12 (2009), s. 1611-1622 ISSN 0010-0765 R&D Projects: GA AV ČR(CZ) KAN200040651; GA MŠk(CZ) LC06035; GA ČR(CZ) GA202/08/1688 Grant - others:GA MŠk(CZ) 1M0528 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : hanging mercury drop electrode * cytosine * 2D condensation Subject RIV: BO - Biophysics Impact factor: 0.856, year: 2009

Inhibitory effect of gene combination in a mouse model of colon cancer with liver metastasis.

Science.gov (United States)

DU, Tong; Niu, Hongxin

2014-09-01

The aim of the present study was to establish an animal liver metastasis model with human colon cancer and investigate the inhibitory effect of the wild type (WT) p53 gene combined with thymidine kinase/ganciclovir (TK/GCV) and cytosine deaminase/5-fluorocytosine (CD/5-FC) systems on liver metastasis of colon cancer. A nude mouse liver metastasis model with human colon cancer was established via a spleen cultivation method. A total of 32 nude mice were randomly divided into four groups, each group with eight mice. Group 1 mice received splenic injections of SW480 cells (control group), while group 2 mice were injected with SW480/p53 cells in the spleen. Group 3 mice were administered splenic injections of SW480/TK-CD cells, and GCV and 5-FC were injected into the abdominal cavity. Finally, group 4 mice received splenic injections of SW480/p53 cells mixed in equal proportion with SW480/TK-CD cells, as well as GCV and 5-FC injections in the abdominal cavity. These cells described were constructed in our laboratory and other laboratories. The number of liver metastatic tumors, the liver metastasis rate, conventional pathology, electron microscopy and other indicators in the nude mice of each group were compared and observed. The nude mouse liver metastasis model with human colon cancer was successfully established; the liver metastasis rate of the control group was 100%. The results demonstrated that the rate of liver metastasis in the nude mice in each treatment group decreased, as well as the average number of liver metastatic tumors. Furthermore, the effect of the treatment group with genetic combination (group 4) was the most effective, demonstrating that WTp53 had a synergistic effect with TK/GCV and CD/5-FC. Therefore, the present study successfully established a mouse model of liver metastasis with colon cancer by injecting human colon cancer cells in the spleen. Combined gene therapy was shown to have a synergistic effect, which effectively inhibited the

Improved negative selection protocol for Plasmodium berghei in the rodent malarial model

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Orr Rachael Y

2012-03-01

Full Text Available Abstract An improved methodology is presented here for transgenic Plasmodium berghei lines that express the negative selectable marker yFCU (a bifunctional protein that combines yeast cytosine deaminase and uridyl phosphoribosyl transferase (UPRT and substitutes delivery of selection drug 5-fluorocytosine (5FC by intraperitoneal injection for administration via the drinking water of the mice. The improved methodology is shown to be as effective, less labour-intensive, reduces animal handling and animal numbers required for successful selection thereby contributing to two of the "three Rs" of animal experimentation, namely refinement and reduction.

The Impact of DNA Topology and Guide Length on Target Selection by a Cytosine-Specific Cas9.

Science.gov (United States)

Tsui, Tsz Kin Martin; Hand, Travis H; Duboy, Emily C; Li, Hong

2017-06-16

Cas9 is an RNA-guided DNA cleavage enzyme being actively developed for genome editing and gene regulation. To be cleaved by Cas9, a double stranded DNA, or the protospacer, must be complementary to the guide region, typically 20-nucleotides in length, of the Cas9-bound guide RNA, and adjacent to a short Cas9-specific element called Protospacer Adjacent Motif (PAM). Understanding the correct juxtaposition of the protospacer- and PAM-interaction with Cas9 will enable development of versatile and safe Cas9-based technology. We report identification and biochemical characterization of Cas9 from Acidothermus cellulolyticus (AceCas9). AceCas9 depends on a 5'-NNNCC-3' PAM and is more efficient in cleaving negative supercoils than relaxed DNA. Kinetic as well as in vivo activity assays reveal that AceCas9 achieves optimal activity when combined with a guide RNA containing a 24-nucleotide complementarity region. The cytosine-specific, DNA topology-sensitive, and extended guide-dependent properties of AceCas9 may be explored for specific genome editing applications.

APOBEC3G enhances lymphoma cell radioresistance by promoting cytidine deaminase-dependent DNA repair.

Science.gov (United States)

Nowarski, Roni; Wilner, Ofer I; Cheshin, Ori; Shahar, Or D; Kenig, Edan; Baraz, Leah; Britan-Rosich, Elena; Nagler, Arnon; Harris, Reuben S; Goldberg, Michal; Willner, Itamar; Kotler, Moshe

2012-07-12

APOBEC3 proteins catalyze deamination of cytidines in single-stranded DNA (ssDNA), providing innate protection against retroviral replication by inducing deleterious dC > dU hypermutation of replication intermediates. APOBEC3G expression is induced in mitogen-activated lymphocytes; however, no physiologic role related to lymphoid cell proliferation has yet to be determined. Moreover, whether APOBEC3G cytidine deaminase activity transcends to processing cellular genomic DNA is unknown. Here we show that lymphoma cells expressing high APOBEC3G levels display efficient repair of genomic DNA double-strand breaks (DSBs) induced by ionizing radiation and enhanced survival of irradiated cells. APOBEC3G transiently accumulated in the nucleus in response to ionizing radiation and was recruited to DSB repair foci. Consistent with a direct role in DSB repair, inhibition of APOBEC3G expression or deaminase activity resulted in deficient DSB repair, whereas reconstitution of APOBEC3G expression in leukemia cells enhanced DSB repair. APOBEC3G activity involved processing of DNA flanking a DSB in an integrated reporter cassette. Atomic force microscopy indicated that APOBEC3G multimers associate with ssDNA termini, triggering multimer disassembly to multiple catalytic units. These results identify APOBEC3G as a prosurvival factor in lymphoma cells, marking APOBEC3G as a potential target for sensitizing lymphoma to radiation therapy.

Isoschizomers and amplified fragment length polymorphism for the detection of specific cytosine methylation changes.

Science.gov (United States)

Ruiz-García, Leonor; Cabezas, Jose Antonio; de María, Nuria; Cervera, María-Teresa

2010-01-01

Different molecular techniques have been developed to study either the global level of methylated cytosines or methylation at specific gene sequences. One of them is a modification of the Amplified Fragment Length Polymorphism (AFLP) technique that has been used to study methylation of anonymous CCGG sequences in different fungi, plant and animal species. The main variation of this technique is based on the use of isoschizomers with different methylation sensitivity (such as HpaII and MspI) as a frequent cutter restriction enzyme. For each sample, AFLP analysis is performed using both EcoRI/HpaII and EcoRI/MspI digested samples. Comparative analysis between EcoRI/HpaII and EcoRI/MspI fragment patterns allows the identification of two types of polymorphisms: (1) "Methylation-insensitive polymorphisms" that show common EcoRI/HpaII and EcoRI/MspI patterns but are detected as polymorphic amplified fragments among samples; and (2) "Methylation-sensitive polymorphisms" that are associated with amplified fragments differing in their presence or absence or in their intensity between EcoRI/HpaII and EcoRI/MspI patterns. This chapter describes a detailed protocol of this technique and discusses modifications that can be applied to adjust the technology to different species of interest.

Assessing somatic hypermutation in Ramos B cells after overexpression or knockdown of specific genes.

Science.gov (United States)

Upton, Dana C; Unniraman, Shyam

2011-11-01

B cells start their life with low affinity antibodies generated by V(D)J recombination. However, upon detecting a pathogen, the variable (V) region of an immunoglobulin (Ig) gene is mutated approximately 100,000-fold more than the rest of the genome through somatic hypermutation (SHM), resulting in high affinity antibodies. In addition, class switch recombination (CSR) produces antibodies with different effector functions depending on the kind of immune response that is needed for a particular pathogen. Both CSR and SHM are initiated by activation-induced cytidine deaminase (AID), which deaminates cytosine residues in DNA to produce uracils. These uracils are processed by error-prone forms of repair pathways, eventually leading to mutations and recombination. Our current understanding of the molecular details of SHM and CSR come from a combination of studies in mice, primary cells, cell lines, and cell-free experiments. Mouse models remain the gold standard with genetic knockouts showing critical roles for many repair factors (e.g. Ung, Msh2, Msh6, Exo1, and polymerase η). However, not all genes are amenable for knockout studies. For example, knockouts of several double-strand break repair proteins are embryonically lethal or impair B-cell development. Moreover, sometimes the specific function of a protein in SHM or CSR may be masked by more global defects caused by the knockout. In addition, since experiments in mice can be lengthy, altering expression of individual genes in cell lines has become an increasingly popular first step to identifying and characterizing candidate genes. Ramos - a Burkitt lymphoma cell line that constitutively undergoes SHM - has been a popular cell-line model to study SHM. One advantage of Ramos cells is that they have a built-in convenient semi-quantitative measure of SHM. Wild type cells express IgM and, as they pick up mutations, some of the mutations knock out IgM expression. Therefore, assaying IgM loss by fluorescence

Automated quantum chemistry based molecular dynamics simulations of electron ionization induced fragmentations of the nucleobases Uracil, Thymine, Cytosine, and Guanine.

Science.gov (United States)

Grimme, Stefan; Bauer, Christopher Alexander

2015-01-01

The gas-phase decomposition pathways of electron ionization (EI)-induced radical cations of the nucleobases uracil, thymine, cytosine, and guanine are investigated by means of mixed quantum-classical molecular dynamics. No preconceived fragmentation channels are used in the calculations. The results compare well to a plethora of experimental and theoretical data for these important biomolecules. With our combined stochastic and dynamic approach, one can access in an unbiased way the energetically available decomposition mechanisms. Additionally, we are able to separate the EI mass spectra of different tautomers of cytosine and guanine. Our method (previously termed quantum chemistry electron ionization mass spectra) reproduces free nucleobase experimental mass spectra well and provides detailed mechanistic in-sight into high-energy unimolecular decomposition processes.

Growth hormone dose in growth hormone-deficient adults is not associated with IGF-1 gene polymorphisms

NARCIS (Netherlands)

S. Meyer (Silke); S. Schaefer (Stephan); D. Ivan (Diana); L. Stolk (Lisette); P.P. Arp (Pascal); A.G. Uitterlinden (André); P.P. Nawroth (Peter); U. Plöckinger (Ursula); G.K. Stalla (Günter); U. Tuschy (Ulrich); M.M. Weber (Matthias); W.J. Weise (Wolfgang); A. Pfützner (Andreas); P. Kann (Peter)

2009-01-01

textabstractAims: Several SNPs and a microsatellite cytosine-adenine repeat promoter polymorphisms of the IGF-1 gene have been reported to be associated with circulating IGF-1 serum concentrations. Variance in IGF-1 concentrations due to genetic variations may affect different response to growth

Methylation changes of H19 gene in sperms of X-irradiated mouse and maintenance in offspring

International Nuclear Information System (INIS)

Zhu Bin; Huang Xinghua; Chen Jindong; Lu Yachao; Chen Ying; Zhao Jingyong

2006-01-01

The nature of imprinting is just differential methylation of imprinted genes. Unlike the non-imprinted genes, the methylation pattern of imprinted genes established during the period of gametogenesis remains unchangeable after fertilization and during embryo development. It implies that gametogenesis is the key stage for methylation pattern of imprinted genes. The imprinting interfered by exogenous factors during this stage could be inherited to offspring and cause genetic effect. Now many studies have proved that ionizing irradiation could disturb DNA methylation. Here we choose BALB/c mice as a research model and X-ray as interfering source to further clarify it. We discovered that the whole-body irradiation of X-ray to male BALB/c mice could influence the methylation pattern of H 19 gene in sperms, which resulted in some cytosines of partial CpG islands in the imprinting control region could not transform to methylated cytosines. Furthermore, by copulating the interfered male mice with normal female, we analyzed the promoter methylation pattern of H 19 in offspring fetal liver and compared the same to the pattern of male parent in sperms. We found that the majority of methylation changes in offspring liver were related to the ones in their parent sperms. Our data proved that the changes of the H 19 gene methylation pattern interfered by X-ray irradiation could be transmitted and maintained in First-generation offspring

Supramolecular Switches Based on the Guanine–Cytosine (GC) Watson–Crick Pair: Effect of Neutral and Ionic Substituents

NARCIS (Netherlands)

Guerra, C.F.; van der Wijst, T.; Bickelhaupt, F.M.

2006-01-01

We have theoretically analyzed Watson–Crick guanine–cytosine (GC) base pairs in which purine-C8 and/or pyrimidine-C6 positions carry a substituent X = NH−, NH2, NH3+ (N series), O−, OH, or OH2+ (O series), using the generalized gradient approximation (GGA) of density functional theory at the

Quantitative analysis of the experimental cytotoxic drug cyclopentenyl cytosine and its metabolite in plasma with HPLC tandem mass spectrometry

NARCIS (Netherlands)

Schimmel, Kirsten; van Lenthe, Henk; Leen, Rene; Kulik, Willem; Verschuur, Arnauld; Guchelaar, Henk-Jan; van Kuilenburg, André

2008-01-01

The cytotoxic drug cyclopentenyl cytosine (CPEC) is currently being investigated in early clinical trials. Monitoring of plasma levels is required for pharmacokinetic analysis and management of toxicity. This paper describes the analysis of CPEC and cyclopentenyl uracil (CPEU) in plasma by

Selection of efficient salt-tolerant bacteria containing ACC deaminase for promotion of tomato growth under salinity stress

Directory of Open Access Journals (Sweden)

Kannika Chookietwattana* and Kedsukon Maneewan

2012-05-01

Full Text Available For successful application of plant growth promoting bacteria (PGPB in salt-affected soil, bioinoculant with salt-tolerant property is required in order to provide better survival and perform well in the field. The present study aimed to select the most efficient salt-tolerant bacterium containing 1-aminocyclopropane-1-carboxylic acid (ACC deaminase from eighty four bacterial strains and to investigate the effects of the selected bacterium on the germination and growth of tomato (Licopersicon esculentum Mill. cv. Seeda under saline conditions. The Bacillus licheniformis B2r was selected for its ability to utilize ACC as a sole nitrogen source under salinity stress. It also showed a high ACC deaminase activity at 0.6 M NaCl salinity. Tomato plants inoculated with the selected bacterium under various saline conditions (0, 30, 60, 90 and 120 mM NaCl revealed a significant increase in the germination percentage, germination index, root length, and seedling dry weight especially at salinity levels ranging from 30-90 mM NaCl. The work described in this report is an important step in developing an efficient salt-tolerant bioinoculant to facilitate plant growth in saline soil.

Gene Therapy in Cardiac Arrhythmias

Directory of Open Access Journals (Sweden)

Praveen S.V

2006-04-01

Full Text Available Gene therapy has progressed from a dream to a bedside reality in quite a few human diseases. From its first application in adenosine deaminase deficiency, through the years, its application has evolved to vascular angiogenesis and cardiac arrhythmias. Gene based biological pacemakers using viral vectors or mesenchymal cells tested in animal models hold much promise. Induction of pacemaker activity within the left bundle branch can provide stable heart rates. Genetic modification of the AV node mimicking beta blockade can be therapeutic in the management of atrial fibrillation. G protein overexpression to modify the AV node also is experimental. Modification and expression of potassium channel genes altering the delayed rectifier potassium currents may permit better management of congenital long QT syndromes. Arrhythmias in a failing heart are due to abnormal calcium cycling. Potential targets for genetic modulation include the sarcoplasmic reticulum calcium pump, calsequestrin and sodium calcium exchanger.Lastly the ethical concerns need to be addressed.

Curcumin inhibits adenosine deaminase and arginase activities in cadmium-induced renal toxicity in rat kidney

Directory of Open Access Journals (Sweden)

Ayodele Jacob Akinyemi

2017-04-01

Full Text Available In this study, the effect of enzymes involved in degradation of renal adenosine and l-arginine was investigated in rats exposed to cadmium (Cd and treated with curcumin, the principal active phytochemical in turmeric rhizome. Animals were divided into six groups (n = 6: saline/vehicle, saline/curcumin 12.5 mg/kg, saline/curcumin 25 mg/kg, Cd/vehicle, Cd/curcumin 12.5 mg/kg, and Cd/curcumin 25 mg/kg. The results of this study revealed that the activities of renal adenosine deaminase and arginase were significantly increased in Cd-treated rats when compared with the control (p < 0.05. However, co-treatment with curcumin inhibits the activities of these enzymes compared with Cd-treated rats. Furthermore, Cd intoxication increased the levels of some renal biomarkers (serum urea, creatinine, and electrolytes and malondialdehyde level with a concomitant decrease in functional sulfhydryl group and nitric oxide (NO. However, co-treatment with curcumin at 12.5 mg/kg and 25 mg/kg, respectively, increases the nonenzymatic antioxidant status and NO in the kidney, with a concomitant decrease in the levels of malondialdehyde and renal biomarkers. Therefore, our results reinforce the importance of adenosine deaminase and arginase activities in Cd poisoning conditions and suggest some possible mechanisms of action by which curcumin prevent Cd-induced renal toxicity in rats.

Preliminary study of MR diffusion weighted imaging in nude mice models of hepatic Bel7402 tumors after adenovirus-mediated cytosine diaminase-thymidine kinase gene therapy

International Nuclear Information System (INIS)

Jiang Xinqing; Chen Liang; Wu Hongzhen; Huang Jingjun; Wei Xinhua; Mo Lei; Yang Ruimeng; Xiao Xiangsheng

2012-01-01

Objective: To study the characteristics of DWI in nude mice models of hepatic Bel7402 tumors after treatment with adenovirus-mediated cytosine diaminase-thymidine kinase (Ad. CD-TK) double suicide gene therapy, and then to identify whether DWI can be used for assessing curative effect of postoperative tumors. Methods: Thirty nude mice models of hepatic Bel7402 tumors were successfully created using cell suspension method, after the tumor grew to more than 1 cm in diameter, 20 tumor models were treated by intratumoral administration of Ad. CD-TK for 3 days plus intraperitonea (i.p.) treatment with 5-Fc and GCV for the duration of the study.Then they were randomly divided into three groups during 5-Fc and GCV treatment. The remaining 10 tumor models were used as controls. MR scanning were performed in 10 th day before and after tumor implantation in all models by using EPI-SE series and SENSE technology for treatment group. Tumor volumes and ADC values were calculated pretreatment and posttreatment. Cell apoptosis were determined by using TUNEL method. Analyze the change of ADC and apoptosis index (AI) in different times, t test was used for comparison the difference of AI and ADC values respectively. Results: After 10 days,the tumor volumes of the treatment groups and controls were respectively (724.16 ±57.45) mm 3 , (754.57 ± 66.84) mm 3 , with no significant difference (t=0.488, P >0.05). The ADC values of the treatment groups were (0.98 ±0.11) × 10 -3 mm 2 /s,the ones of the control groups were (0.68 ±0.04) × 10 -3 mm 2 /s; AI of the treatment groups were (23.25 ±6.57)%, the ones of the control groups were (2.57 ± 0.58)%. There were difference in both groups (t=4.473, 5.874; P<0.01). Conclusion: DWI can be effectively to monitor the early pathological changes of hepatic Bel7402 tumors after Ad. CD-TK double suicide gene therapy, and provide experimental evidences for clinical application. (authors)

Genome-wide nucleosome map and cytosine methylation levels of an ancient human genome

DEFF Research Database (Denmark)

Pedersen, Jakob Skou; Valen, Eivind; Velazquez, Amhed Missael Vargas

2014-01-01

Epigenetic information is available from contemporary organisms, but is difficult to track back in evolutionary time. Here, we show that genome-wide epigenetic information can be gathered directly from next-generation sequence reads of DNA isolated from ancient remains. Using the genome sequence...... data generated from hair shafts of a 4000-yr-old Paleo-Eskimo belonging to the Saqqaq culture, we generate the first ancient nucleosome map coupled with a genome-wide survey of cytosine methylation levels. The validity of both nucleosome map and methylation levels were confirmed by the recovery...

Error-free versus mutagenic processing of genomic uracil--relevance to cancer.

Science.gov (United States)

Krokan, Hans E; Sætrom, Pål; Aas, Per Arne; Pettersen, Henrik Sahlin; Kavli, Bodil; Slupphaug, Geir

2014-07-01

Genomic uracil is normally processed essentially error-free by base excision repair (BER), with mismatch repair (MMR) as an apparent backup for U:G mismatches. Nuclear uracil-DNA glycosylase UNG2 is the major enzyme initiating BER of uracil of U:A pairs as well as U:G mismatches. Deficiency in UNG2 results in several-fold increases in genomic uracil in mammalian cells. Thus, the alternative uracil-removing glycosylases, SMUG1, TDG and MBD4 cannot efficiently complement UNG2-deficiency. A major function of SMUG1 is probably to remove 5-hydroxymethyluracil from DNA with general back-up for UNG2 as a minor function. TDG and MBD4 remove deamination products U or T mismatched to G in CpG/mCpG contexts, but may have equally or more important functions in development, epigenetics and gene regulation. Genomic uracil was previously thought to arise only from spontaneous cytosine deamination and incorporation of dUMP, generating U:G mismatches and U:A pairs, respectively. However, the identification of activation-induced cytidine deaminase (AID) and other APOBEC family members as DNA-cytosine deaminases has spurred renewed interest in the processing of genomic uracil. Importantly, AID triggers the adaptive immune response involving error-prone processing of U:G mismatches, but also contributes to B-cell lymphomagenesis. Furthermore, mutational signatures in a substantial fraction of other human cancers are consistent with APOBEC-induced mutagenesis, with U:G mismatches as prime suspects. Mutations can be caused by replicative polymerases copying uracil in U:G mismatches, or by translesion polymerases that insert incorrect bases opposite abasic sites after uracil-removal. In addition, kataegis, localized hypermutations in one strand in the vicinity of genomic rearrangements, requires APOBEC protein, UNG2 and translesion polymerase REV1. What mechanisms govern error-free versus error prone processing of uracil in DNA remains unclear. In conclusion, genomic uracil is an

Modification of the cerebral perfusion during a chemotherapy by arabinoside cytosine (A.R.A.C.) among patients suffering of an acute myelo-blastic leukemia (A.M.L.); Modification de la perfusion cerebrale au cours d'une chimiotherapie par cytosine arabinoside (ARAC) chez les patients atteints d'une leucemie aigue myeloblastique (LAM)

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Modzelewski, R.; Vera, P. [Universite de Medecine de Rouen, QUANT.I.F-LITIS EA4108, departement de medecine nucleaire, 76 (France); Lepretre, S.; Tilly, H. [Centre Henri-Becquerel, departement d' hematologie, 76 - Rouen (France); Martinaud, O.; Hannequin, D. [CHU de Rouen, departement de neurologie, 76 (France); Habert, M.O. [CHU de la Pitie-Salpetriere, departement de medecine nucleaire, 75 - Paris (France)

2010-07-01

Cytosine arabinoside in high doses is a major treatment in acute myelo-blastic leukemia (A.M.L.). This treatment leads to neurological complications in 3-16% of cases, but the EEG, CT or MRI are normal.This prospective study examines brain perfusion in single photon emission tomography (SPECT) for patients receiving high dose arabinoside cytosine (H.D. A.R.A.C.). The SPECT of perfusion with hexamethyl propylene amine oxime (H.M.P.A.O.) for patients suffering of A.M.L. allowed to show a reduction of perfusion at the cerebellum level, of the occipito-parietal cortex and thalami, after conventional doses of A.R.A.C., while the patients had not any neurological accidents. (N.C.)

Structure-wise discrimination of cytosine, thymine, and uracil by proteins in terms of their nonbonded interactions.

Science.gov (United States)

Usha, S; Selvaraj, S

2014-01-01

The molecular recognition and discrimination of very similar ligand moieties by proteins are important subjects in protein-ligand interaction studies. Specificity in the recognition of molecules is determined by the arrangement of protein and ligand atoms in space. The three pyrimidine bases, viz. cytosine, thymine, and uracil, are structurally similar, but the proteins that bind to them are able to discriminate them and form interactions. Since nonbonded interactions are responsible for molecular recognition processes in biological systems, our work attempts to understand some of the underlying principles of such recognition of pyrimidine molecular structures by proteins. The preferences of the amino acid residues to contact the pyrimidine bases in terms of nonbonded interactions; amino acid residue-ligand atom preferences; main chain and side chain atom contributions of amino acid residues; and solvent-accessible surface area of ligand atoms when forming complexes are analyzed. Our analysis shows that the amino acid residues, tyrosine and phenyl alanine, are highly involved in the pyrimidine interactions. Arginine prefers contacts with the cytosine base. The similarities and differences that exist between the interactions of the amino acid residues with each of the three pyrimidine base atoms in our analysis provide insights that can be exploited in designing specific inhibitors competitive to the ligands.

Methylation by a unique α-class N4-cytosine methyltransferase is required for DNA transformation of Caldicellulosiruptor bescii DSM6725.

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Daehwan Chung

Full Text Available Thermophilic microorganisms capable of using complex substrates offer special advantages for the conversion of lignocellulosic biomass to biofuels and bioproducts. Members of the gram-positive bacterial genus Caldicellulosiruptor are anaerobic thermophiles with optimum growth temperatures between 65°C and 78°C and are the most thermophilic cellulolytic organisms known. In fact, they efficiently use biomass non-pretreated as their sole carbon source and in successive rounds of application digest 70% of total switchgrass substrate. The ability to genetically manipulate these organisms is a prerequisite to engineering them for use in conversion of these complex substrates to products of interest as well as identifying gene products critical for their ability to utilize non-pretreated biomass. Here, we report the first example of DNA transformation of a member of this genus, C. bescii. We show that restriction of DNA is a major barrier to transformation (in this case apparently absolute and that methylation with an endogenous unique α-class N4-Cytosine methyltransferase is required for transformation of DNA isolated from E. coli. The use of modified DNA leads to the development of an efficient and reproducible method for DNA transformation and the combined frequencies of transformation and recombination allow marker replacement between non-replicating plasmids and chromosomal genes providing the basis for rapid and efficient methods of genetic manipulation.

G22A Polymorphism of Adenosine Deaminase and its Association with Biochemical Characteristics of Gestational Diabetes Mellitus in an Iranian Population

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Mohammad Ali Takhshid

2015-03-01

Full Text Available Adenosine deaminase (ADA is an important regulator of insulin action. The single nucleotide polymorphism (SNP G22A in the ADA gene decreases enzymatic activity of ADA. The aim of this study was to investigate the relationship between the SNP G22A and blood glycemic control, insulin resistance, and obesity of gestational diabetes mellitus (GDM patients in an Iranian population. SNP G22A was determined in women with GDM (N=70 and healthy pregnant women (control, N=70 using polymerase chain reaction-restriction fragment length polymorphism. Fasting plasma glucose (FPG, hemoglobin A1C (HbA1c, plasma insulin levels and plasma lipids were measured using commercial kits. Homeostasis model of assessment for insulin resistance (HOMA-IR was calculated. The distribution of genotypes and alleles among GDM patients was similar to that of the control group. FPG and HbA1c were significantly higher in GDM patients with GG genotype compared with GDM patients with GA+AA genotype and non-GDM patients. The frequency of GG genotype was significantly higher in obese GDM patients compared to lean GDM patients. The SNP G22A in the ADA gene was not associated with the risk of GDM in our population. GG genotype was associated with poor glycemic control and obesity in GDM patients.

Conformational change of adenosine deaminase during ligand-exchange in a crystal.

Science.gov (United States)

Kinoshita, Takayoshi; Tada, Toshiji; Nakanishi, Isao

2008-08-15

Adenosine deaminase (ADA) perpetuates chronic inflammation by degrading extracellular adenosine which is toxic for lymphocytes. ADA has two distinct conformations: open form and closed form. From the crystal structures with various ligands, the non-nucleoside type inhibitors bind to the active site occupying the critical water-binding-position and sustain the open form of apo-ADA. In contrast, substrate mimics do not occupy the critical position, and induce the large conformational change to the closed form. However, it is difficult to predict the binding of (+)-erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), as it possesses characteristic parts of both the substrate and the non-nucleoside inhibitors. The crystal structure shows that EHNA binds to the open form through a novel recognition of the adenine base accompanying conformational change from the closed form of the PR-ADA complex in crystalline state.

Interaction of Cu+ with cytosine and formation of i-motif-like C-M+-C complexes: alkali versus coinage metals

NARCIS (Netherlands)

Gao, J.; Berden, G.; Rodgers, M.T.; Oomens, J.

2016-01-01

The Watson-Crick structure of DNA is among the most well-known molecular structures of our time. However, alternative base-pairing motifs are also known to occur, often depending on base sequence, pH, or the presence of cations. Pairing of cytosine (C) bases induced by the sharing of a single proton

Involvement of activation-induced cytidine deaminase in skin cancer development.

Science.gov (United States)

Nonaka, Taichiro; Toda, Yoshinobu; Hiai, Hiroshi; Uemura, Munehiro; Nakamura, Motonobu; Yamamoto, Norio; Asato, Ryo; Hattori, Yukari; Bessho, Kazuhisa; Minato, Nagahiro; Kinoshita, Kazuo

2016-04-01

Most skin cancers develop as the result of UV light-induced DNA damage; however, a substantial number of cases appear to occur independently of UV damage. A causal link between UV-independent skin cancers and chronic inflammation has been suspected, although the precise mechanism underlying this association is unclear. Here, we have proposed that activation-induced cytidine deaminase (AID, encoded by AICDA) links chronic inflammation and skin cancer. We demonstrated that Tg mice expressing AID in the skin spontaneously developed skin squamous cell carcinoma with Hras and Trp53 mutations. Furthermore, genetic deletion of Aicda reduced tumor incidence in a murine model of chemical-induced skin carcinogenesis. AID was expressed in human primary keratinocytes in an inflammatory stimulus-dependent manner and was detectable in human skin cancers. Together, the results of this study indicate that inflammation-induced AID expression promotes skin cancer development independently of UV damage and suggest AID as a potential target for skin cancer therapeutics.

Hypermutation by intersegmental transfer of APOBEC3G cytidine deaminase.

Science.gov (United States)

Nowarski, Roni; Britan-Rosich, Elena; Shiloach, Tamar; Kotler, Moshe

2008-10-01

Deamination of cytidine residues in single-stranded DNA (ssDNA) is an important mechanism by which apolipoprotein B mRNA-editing, catalytic polypeptide-like (APOBEC) enzymes restrict endogenous and exogenous viruses. The dynamic process underlying APOBEC-induced hypermutation is not fully understood. Here we show that enzymatically active APOBEC3G can be detected in wild-type Vif(+) HIV-1 virions, albeit at low levels. In vitro studies showed that single enzyme-DNA encounters result in distributive deamination of adjacent cytidines. Nonlinear translocation of APOBEC3G, however, directed scattered deamination of numerous targets along the DNA. Increased ssDNA concentrations abolished enzyme processivity in the case of short, but not long, DNA substrates, emphasizing the key role of rapid intersegmental transfer in targeting the deaminase. Our data support a model by which APOBEC3G intersegmental transfer via monomeric binding to two ssDNA segments results in dispersed hypermutation of viral genomes.

Effects of an induced adenosine deaminase deficiency on T-cell differentiation in the rat

International Nuclear Information System (INIS)

Barton, R.W.

1985-01-01

Inherited deficiency of the enzyme adenosine deaminase (ADA) has been found in a significant proportion of patients with severe combined immunodeficiency disease and inherited defect generally characterized by a deficiency of both B and T cells. Two questions are central to understanding the pathophysiology of this disease: (1) at what stage or stages in lymphocyte development are the effects of the enzyme deficiency manifested; (2) what are the biochemical mechanisms responsible for the selective pathogenicity of the lymphoid system. We have examined the stage or stages of rat T-cell development in vivo which are affected by an induced adenosine deaminase deficiency using the ADA inhibitors, erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA) and 2'-deoxycoformycin (DCF). In normal rats given daily administration of an ADA inhibitor, cortical thymocytes were markedly depleted; peripheral lymphocytes and pluripotent hemopoietic stem cells (CFU-S) all were relatively unaffected. Since a deficiency of ADA affects lymphocyte development, the regeneration of cortical and medullary thymocytes and their precursors after sublethal irradiation was used as a model of lymphoid development. By Day 5 after irradiation the thymus was reduced to 0.10-0.5% of its normal size; whereas at Days 9 and 14 the thymus was 20-40% and 60-80% regenerated, respectively. When irradiated rats were given daily parenteral injections of the ADA inhibitor plus adenosine or deoxyadenosine, thymus regeneration at Days 9 and 14 was markedly inhibited, whereas the regeneration of thymocyte precursors was essentially unaffected. Thymus regeneration was at least 40-fold lower than in rats given adenosine or deoxyadenosine alone. Virtually identical results were obtained with both ADA inhibitors, EHNA and DCF

Editing of HIV-1 RNA by the double-stranded RNA deaminase ADAR1 stimulates viral infection

Science.gov (United States)

Doria, Margherita; Neri, Francesca; Gallo, Angela; Farace, Maria Giulia; Michienzi, Alessandro

2009-01-01

Adenosine deaminases that act on dsRNA (ADARs) are enzymes that target double-stranded regions of RNA converting adenosines into inosines (A-to-I editing) thus contributing to genome complexity and fine regulation of gene expression. It has been described that a member of the ADAR family, ADAR1, can target viruses and affect their replication process. Here we report evidence showing that ADAR1 stimulates human immuno deficiency virus type 1 (HIV-1) replication by using both editing-dependent and editing-independent mechanisms. We show that over-expression of ADAR1 in HIV-1 producer cells increases viral protein accumulation in an editing-independent manner. Moreover, HIV-1 virions generated in the presence of over-expressed ADAR1 but not an editing-inactive ADAR1 mutant are released more efficiently and display enhanced infectivity, as demonstrated by challenge assays performed with T cell lines and primary CD4+ T lymphocytes. Finally, we report that ADAR1 associates with HIV-1 RNAs and edits adenosines in the 5′ untranslated region (UTR) and the Rev and Tat coding sequence. Overall these results suggest that HIV-1 has evolved mechanisms to take advantage of specific RNA editing activity of the host cell and disclose a stimulatory function of ADAR1 in the spread of HIV-1. PMID:19651874

Rapid and accurate synthesis of TALE genes from synthetic oligonucleotides.

Science.gov (United States)

Wang, Fenghua; Zhang, Hefei; Gao, Jingxia; Chen, Fengjiao; Chen, Sijie; Zhang, Cuizhen; Peng, Gang

2016-01-01

Custom synthesis of transcription activator-like effector (TALE) genes has relied upon plasmid libraries of pre-fabricated TALE-repeat monomers or oligomers. Here we describe a novel synthesis method that directly incorporates annealed synthetic oligonucleotides into the TALE-repeat units. Our approach utilizes iterative sets of oligonucleotides and a translational frame check strategy to ensure the high efficiency and accuracy of TALE-gene synthesis. TALE arrays of more than 20 repeats can be constructed, and the majority of the synthesized constructs have perfect sequences. In addition, this novel oligonucleotide-based method can readily accommodate design changes to the TALE repeats. We demonstrated an increased gene targeting efficiency against a genomic site containing a potentially methylated cytosine by incorporating non-conventional repeat variable di-residue (RVD) sequences.

Cell Cycle Regulates Nuclear Stability of AID and Determines the Cellular Response to AID.

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Quy Le

2015-09-01

Full Text Available AID (Activation Induced Deaminase deaminates cytosines in DNA to initiate immunoglobulin gene diversification and to reprogram CpG methylation in early development. AID is potentially highly mutagenic, and it causes genomic instability evident as translocations in B cell malignancies. Here we show that AID is cell cycle regulated. By high content screening microscopy, we demonstrate that AID undergoes nuclear degradation more slowly in G1 phase than in S or G2-M phase, and that mutations that affect regulatory phosphorylation or catalytic activity can alter AID stability and abundance. We directly test the role of cell cycle regulation by fusing AID to tags that destabilize nuclear protein outside of G1 or S-G2/M phases. We show that enforced nuclear localization of AID in G1 phase accelerates somatic hypermutation and class switch recombination, and is well-tolerated; while nuclear AID compromises viability in S-G2/M phase cells. We identify AID derivatives that accelerate somatic hypermutation with minimal impact on viability, which will be useful tools for engineering genes and proteins by iterative mutagenesis and selection. Our results further suggest that use of cell cycle tags to regulate nuclear stability may be generally applicable to studying DNA repair and to engineering the genome.

Synthesis, Characterization, and Physicochemical Studies of Mixed Ligand Complexes of Inner Transition Metals with Lansoprazole and Cytosine

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Sarika Verma

2013-01-01

Full Text Available Few complexes of inner transition metals [Th(IV, Ce(IV, Nd(III, Gd(III] have been synthesized by reacting their metal salts with lansoprazole, 2-([3-methyl-4-(2,2,2-trifluoroethoxypyridin-2-yl]methylsulfinyl-1H-benzoimidazole and cytosine. All the complexes were synthesized in ethanolic medium. The yield percentage rangs from 80 to 90%. The complexes are coloured solids. The complexes were characterized through elemental analyses, conductance measurements, and spectroscopic methods (FT IR, FAB Mass, 1H NMR and UV. An IR spectrum indicates that the ligand behaves as bidentate ligands. The metal complexes have been screened for their antifungal activity towards Aspergillus niger fungi. The interaction of inner transition metals with lansoprazole, in presence of cytosine, has also been investigated potentiometrically at two different temperatures 26±1°C and 36±1°C and at 0.1 M (KNO3 ionic strength. The stability constants of ternary complexes indicate the stability order as Th(IV < Ce(IV < Gd(III < Nd(III. logK values obtained are positive and suggest greater stabilization of ternary complexes. The values of thermodynamic parameters (free energy (ΔG, enthalpy (ΔH, and entropy (ΔS are also calculated.

Nitric oxide - an activating factor of adenosine deaminase 2 in vitro.

Science.gov (United States)

Sargisova, Ye G; Andreasyan, N A; Hayrapetyan, H L; Harutyunyan, H A

2012-01-01

In this study we have investigated the effect of reactive oxygen species produced by some chemicals in aqueous solutions on activity of adenosine deaminase 2 (ADA2) purified from human blood plasma. An activating effect on ADA2 was observed in vitro with sodium nitroprusside (SNP), the source of NO (nitrosonium ions NO(-) in aqueous solutions). Not SH-groups of cysteine but other amino acid residues sensitive to NO were responsible for ADA2 activation. The SNP-derived activation was more pronounced when purified ADA2 was preincubated with heparin and different proteins as an experimental model of the protein environment in vivo. The most effective was heparin, which is known for its ability to regulate enzyme and protein functions in extracellular matrix. We conclude that ADA2 is a protein with flexible conformation that is affected by the protein environment, and it changes its activity under oxidative (nitrosative) stress.

Methylobacterium oryzae sp. nov., an aerobic, pink-pigmented, facultatively methylotrophic, 1-aminocyclopropane-1-carboxylate deaminase-producing bacterium isolated from rice.

Science.gov (United States)

Madhaiyan, Munusamy; Kim, Byung-Yong; Poonguzhali, Selvaraj; Kwon, Soon-Wo; Song, Myung-Hee; Ryu, Jeoung-Hyun; Go, Seung-Joo; Koo, Bon-Sung; Sa, Tong-Min

2007-02-01

A pink-pigmented, facultatively methylotrophic bacterium, strain CBMB20T, isolated from stem tissues of rice, was analysed by a polyphasic approach. Strain CBMB20T utilized 1-aminocyclopropane 1-carboxylate (ACC) as a nitrogen source and produced ACC deaminase. It was related phylogenetically to members of the genus Methylobacterium. 16S rRNA gene sequence analysis indicated that strain CBMB20T was most closely related to Methylobacterium fujisawaense, Methylobacterium radiotolerans and Methylobacterium mesophilicum; however, DNA-DNA hybridization values were less than 70 % with the type strains of these species. The DNA G+C content of strain CBMB20T was 70.6 mol%. The study presents a detailed phenotypic characterization of strain CBMB20T that allows its differentiation from other Methylobacterium species. In addition, strain CBMB20T is the only known member of the genus Methylobacterium to be described from the phyllosphere of rice. Based on the data presented, strain CBMB20T represents a novel species in the genus Methylobacterium, for which the name Methylobacterium oryzae sp. nov. is proposed, with strain CBMB20T (=DSM 18207T=LMG 23582T=KACC 11585T) as the type strain.

Comparative effectiveness of ACC-deaminase and/or nitrogen-fixing rhizobacteria in promotion of maize (Zea mays L.) growth under lead pollution.

Science.gov (United States)

Hassan, Waseem; Bano, Rizwana; Bashir, Farhat; David, Julie

2014-09-01

Lead (Pb) pollution is appearing as an alarming threat nowadays. Excessive Pb concentrations in agricultural soils result in minimizing the soil fertility and health which affects the plant growth and leads to decrease in crop production. Plant growth promoting rhizobacteria (PGPR) are beneficial bacteria which can protect the plants against many abiotic stresses, and enhance the growth. The study aimed to identify important rhizobacterial strains by using the 1-aminocyclopropane-1-carboxylate (ACC) enrichment technique and examine their inoculation effects in the growth promotion of maize, under Pb pollution. A pot experiment was conducted and six rhizobacterial isolates were used. Pb was added to 2 kg soil in each pot (with 4 seeds/pot) using Pb(NO3)2 at the rate of 0, 100, 200, 300, and 400 mg kg(-1) Pb with three replications in completely randomized design. Rhizobacterial isolates performed significantly better under all Pb levels, i.e., 100 to 400 Pb mg kg(-1) soil, compared to control. Comparing the efficacy of the rhizobacterial isolates under different Pb levels, rhizobacterial isolates having both ACC-deaminase and nitrogen-fixing activities (AN8 and AN12) showed highest increase in terms of the physical, chemical and enzymatic growth parameters of maize, followed by the rhizobacterial isolates having ACC-deaminase activity only (ACC5 and ACC8), and then the nitrogen-fixing rhizobia (Azotobacter and RN5). However, the AN8 isolate showed maximum efficiency, and highest shoot and root length (14.2 and 6.1 cm), seedling fresh and dry weights (1.91 and 0.14 g), chlorophyll a, b, and carotenoids (24.1, 30.2 and 77.7 μg/l), protein (0.82 mg/g), proline (3.42 μmol/g), glutathione S-transferase, peroxidase and catalase (12.3, 4.2 and 7.2 units/mg protein), while the lowest Pb uptake in the shoot and root (0.83 and 0.48 mg/kg) were observed under this rhizobial isolate at the highest Pb level (i.e., 400 Pb mg kg(-1) soil). The results revealed that PGPR

Correlating Gene-specific DNA Methylation Changes with Expression and Transcriptional Activity of Astrocytic KCNJ10 (Kir4.1).

Science.gov (United States)

Nwaobi, Sinifunanya E; Olsen, Michelle L

2015-09-26

DNA methylation serves to regulate gene expression through the covalent attachment of a methyl group onto the C5 position of a cytosine in a cytosine-guanine dinucleotide. While DNA methylation provides long-lasting and stable changes in gene expression, patterns and levels of DNA methylation are also subject to change based on a variety of signals and stimuli. As such, DNA methylation functions as a powerful and dynamic regulator of gene expression. The study of neuroepigenetics has revealed a variety of physiological and pathological states that are associated with both global and gene-specific changes in DNA methylation. Specifically, striking correlations between changes in gene expression and DNA methylation exist in neuropsychiatric and neurodegenerative disorders, during synaptic plasticity, and following CNS injury. However, as the field of neuroepigenetics continues to expand its understanding of the role of DNA methylation in CNS physiology, delineating causal relationships in regards to changes in gene expression and DNA methylation are essential. Moreover, in regards to the larger field of neuroscience, the presence of vast region and cell-specific differences requires techniques that address these variances when studying the transcriptome, proteome, and epigenome. Here we describe FACS sorting of cortical astrocytes that allows for subsequent examination of a both RNA transcription and DNA methylation. Furthermore, we detail a technique to examine DNA methylation, methylation sensitive high resolution melt analysis (MS-HRMA) as well as a luciferase promoter assay. Through the use of these combined techniques one is able to not only explore correlative changes between DNA methylation and gene expression, but also directly assess if changes in the DNA methylation status of a given gene region are sufficient to affect transcriptional activity.

Distribution of adenosine deaminase complexing protein (ADCP) in human tissues.

Science.gov (United States)

Dinjens, W N; ten Kate, J; van der Linden, E P; Wijnen, J T; Khan, P M; Bosman, F T

1989-12-01

The normal distribution of adenosine deaminase complexing protein (ADCP) in the human body was investigated quantitatively by ADCP-specific radioimmunoassay (RIA) and qualitatively by immunohistochemistry. In these studies we used a specific rabbit anti-human ADCP antiserum. In all 19 investigated tissues, except erythrocytes, ADCP was found by RIA in the soluble and membrane fractions. From all tissues the membrane fractions contained more ADCP (expressed per mg protein) than the soluble fractions. High membrane ADCP concentrations were found in skin, renal cortex, gastrointestinal tract, and prostate. Immunoperoxidase staining confirmed the predominant membrane-associated localization of the protein. In serous sweat glands, convoluted tubules of renal cortex, bile canaliculi, gastrointestinal tract, lung, pancreas, prostate gland, salivary gland, gallbladder, mammary gland, and uterus, ADCP immunoreactivity was found confined to the luminal membranes of the epithelial cells. These data demonstrate that ADCP is present predominantly in exocrine glands and absorptive epithelia. The localization of ADCP at the secretory or absorptive apex of the cells suggests that the function of ADCP is related to the secretory and/or absorptive process.

Piracetam prevents scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities.

Science.gov (United States)

Marisco, Patricia C; Carvalho, Fabiano B; Rosa, Michelle M; Girardi, Bruna A; Gutierres, Jessié M; Jaques, Jeandre A S; Salla, Ana P S; Pimentel, Víctor C; Schetinger, Maria Rosa C; Leal, Daniela B R; Mello, Carlos F; Rubin, Maribel A

2013-08-01

Piracetam improves cognitive function in animals and in human beings, but its mechanism of action is still not completely known. In the present study, we investigated whether enzymes involved in extracellular adenine nucleotide metabolism, adenosine triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase and adenosine deaminase (ADA) are affected by piracetam in the hippocampus and cerebral cortex of animals subjected to scopolamine-induced memory impairment. Piracetam (0.02 μmol/5 μL, intracerebroventricular, 60 min pre-training) prevented memory impairment induced by scopolamine (1 mg/kg, intraperitoneal, immediately post-training) in the inhibitory avoidance learning and in the object recognition task. Scopolamine reduced the activity of NTPDase in hippocampus (53 % for ATP and 53 % for ADP hydrolysis) and cerebral cortex (28 % for ATP hydrolysis). Scopolamine also decreased the activity of 5'-nucleotidase (43 %) and ADA (91 %) in hippocampus. The same effect was observed in the cerebral cortex for 5'-nucleotidase (38 %) and ADA (68 %) activities. Piracetam fully prevented scopolamine-induced memory impairment and decrease of NTPDase, 5'-nucleotidase and adenosine deaminase activities in synaptosomes from cerebral cortex and hippocampus. In vitro experiments show that piracetam and scopolamine did not alter enzymatic activity in cerebral cortex synaptosomes. Moreover, piracetam prevented scopolamine-induced increase of TBARS levels in hippocampus and cerebral cortex. These results suggest that piracetam-induced improvement of memory is associated with protection against oxidative stress and maintenance of NTPDase, 5'-nucleotidase and ADA activities, and suggest the purinergic system as a putative target of piracetam.

Effects of temperature and isotopic substitution on electron attachment dynamics of guanine–cytosine base pair: Ring-polymer and classical molecular dynamics simulations

International Nuclear Information System (INIS)

Minoshima, Yusuke; Seki, Yusuke; Takayanagi, Toshiyuki; Shiga, Motoyuki

2016-01-01

Highlights: • Dynamics of excess electron attachment to guanine–cytosine base pair. • Ring-polymer and classical molecular dynamics simulations are performed. • Temperature and isotope substitution effects are investigated. - Abstract: The dynamical process of electron attachment to a guanine–cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.

Effects of temperature and isotopic substitution on electron attachment dynamics of guanine–cytosine base pair: Ring-polymer and classical molecular dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Minoshima, Yusuke; Seki, Yusuke [Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570 (Japan); Takayanagi, Toshiyuki, E-mail: tako@mail.saitama-u.ac.jp [Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570 (Japan); Shiga, Motoyuki [Center for Computational Science and E-Systems, Japan Atomic Energy Agency, 148-4, Kashiwanoha Campus, 178-4 Wakashiba, Kashiwa, Chiba 277-0871 (Japan)

2016-06-15

Highlights: • Dynamics of excess electron attachment to guanine–cytosine base pair. • Ring-polymer and classical molecular dynamics simulations are performed. • Temperature and isotope substitution effects are investigated. - Abstract: The dynamical process of electron attachment to a guanine–cytosine pair in the normal (h-GC) and deuterated (d-GC) forms has been studied theoretically by semiclassical ring-polymer molecular dynamics (RPMD) simulations using the empirical valence bond model. The initially formed dipole-bound anion is converted rapidly to the valence-bound anion within about 0.1 ps in both h-GC and d-GC. However, the subsequent proton transfer in h-GC occurs with a rate five times greater than the deuteron transfer in d-GC. The change of rates with isotopic substitution and temperature variation in the RPMD simulations are quantitatively and qualitatively different from those in the classical molecular dynamics (MD) simulations, demonstrating the importance of nuclear quantum effects on the dynamics of this system.

Intramolecular tautomerisation and the conformational variability of some classical mutagens – cytosine derivatives: quantum chemical study

Directory of Open Access Journals (Sweden)

Hovorun D. M.

2011-04-01

Full Text Available Aim. To determine the lifetime of the mutagenic cytosine derivatives through the investigation of the physicochemical mechanisms of their intramolecular proton transfer. Methods. Non-empirical quantum chemistry, the analysis of the electron density by means of Bader’s atoms in molecules (AIM theory and physicochemical kinetics were used. Results. It is shown that the modification of all investigated compounds, except DCyt, prevents their pairing in both mutagenic and canonical tautomeric forms with a base which is an interacting partner. This effect can inhibit their mutagenic potential. It is also established that Watson-Crick tautomeric hypothesis can be formally expanded for the investigated molecules so far as a lifetime of the mutagenic tautomers much more exceeds characteristic time for the incorporation of one nucleotides pair by DNA biosynthesis machinery. It seems that just within the frame of this hypothesis it will be possible to give an adequate explanation of the mechanisms of mutagenic action of N4-aminocytosine, N4-methoxycytosine, N4-hydroxycytosine and N4dehydrocytosine, which have much more energy advantageous imino form in comparison with amino form. Conclusions. For the first time the comprehensive conformational analysis of a number of classical mutagens, namely cytosine derivatives, has been performed using the methods of non-empirical quantum chemistry at the MP2/6-311++G (2df,pd//B3LYP/6-311++G(d,p level of theory

Cyclopentenyl cytosine has biological and anti-tumour activity, but does not enhance the efficacy of gemcitabine and radiation in two animal tumour models

NARCIS (Netherlands)

van Bree, Chris; Barten-van Rijbroek, Angeliqué D.; Leen, René; Rodermond, Hans M.; van Kuilenburg, André B. P.; Kal, Henk B.

2009-01-01

Cyclopentenyl cytosine (CPEC), targetting the de novo biosynthesis of cytidine triphosphate (CTP), increases the cytotoxicity of gemcitabine (2',2'-difluoro-2'-deoxycytidine, dFdC) alone and in combination with irradiation in several human tumour cells in vitro. We investigated whether OPEC enhances

Ionophoretic method in the study of mixed ligand ternary chelates of UO2(II), Ni(II) and Zn(II) involving nitrilotriacetate and cytosine as ligands

International Nuclear Information System (INIS)

Mishra, A.P.; Mishra, S.K.; Yadava, K.L.

1987-01-01

A novel electrophoretic technique is described for the assessment of the equilibria in mixed-ligand complex system in solution. It is based on the movement of spot of the metal ion under an electric field with the complexants added in the background electrolyte at fixed pH. The concentration of primary ligand nitrilotriacetate was constant while that of secondary ligand (cytosine) was varied. The plot of log (cytosine) against mobility was used to obtain information on the formation of the mixed complexes and to calculate its stability constants. Experimentally obtained logK values are as 5.62, 4.55 and 4.42 for mixed complexes of UO 2 (II), Ni(II) and Zn(II) respectively at μ=0.1 and temp.=35 +- 01.degC. (author). 10 refs

Advances of gene therapy for primary immunodeficiencies [version 1; referees: 2 approved

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Fabio Candotti

2016-03-01

Full Text Available In the recent past, the gene therapy field has witnessed a remarkable series of successes, many of which have involved primary immunodeficiency diseases, such as X-linked severe combined immunodeficiency, adenosine deaminase deficiency, chronic granulomatous disease, and Wiskott-Aldrich syndrome. While such progress has widened the choice of therapeutic options in some specific cases of primary immunodeficiency, much remains to be done to extend the geographical availability of such an advanced approach and to increase the number of diseases that can be targeted. At the same time, emerging technologies are stimulating intensive investigations that may lead to the application of precise genetic editing as the next form of gene therapy for these and other human genetic diseases.

Dynamics of self-assembled cytosine nucleobases on graphene

Science.gov (United States)

Saikia, Nabanita; Johnson, Floyd; Waters, Kevin; Pandey, Ravindra

2018-05-01

Molecular self-assembly of cytosine (C n ) bases on graphene was investigated using molecular dynamics methods. For free-standing C n bases, simulation conditions (gas versus aqueous) determine the nature of self-assembly; the bases prefer to aggregate in the gas phase and are stabilized by intermolecular H-bonds, while in the aqueous phase, the water molecules disrupt base-base interactions, which facilitate the formation of π-stacked domains. The substrate-induced effects, on the other hand, find the polarity and donor-acceptor sites of the bases to govern the assembly process. For example, in the gas phase, the assembly of C n bases on graphene displays short-range ordered linear arrays stabilized by the intermolecular H-bonds. In the aqueous phase, however, there are two distinct configurations for the C n bases assembly on graphene. For the first case corresponding to low surface coverage, the bases are dispersed on graphene and are isolated. The second configuration archetype is disordered linear arrays assembled with medium and high surface coverage. The simulation results establish the role of H-bonding, vdW π-stacking, and the influence of graphene surface towards the self-assembly. The ability to regulate the assembly into well-defined patterns can aid in the design of self-assembled nanostructures for the next-generation DNA based biosensors and nanoelectronic devices.

Partial resolution of bone lesions. A child with severe combined immunodeficiency disease and adenosine deaminase deficiency after enzyme-replacement therapy

International Nuclear Information System (INIS)

Yulish, B.S.; Stern, R.C.; Polmar, S.H.

1980-01-01

A child with severe combined immunodeficiency disease and adenosine deaminase deficiency, with characteristic bone dysplasia, was treated with transfusions of frozen irradiated RBCs as a means of enzyme replacement. This therapy resulted in restoration of immunologic competence and partial resolution of the bone lesions. Although the natural history of these lesions without therapy is not known, enzyme-replacement therapy may have played a role in the resolution of this patient's bone lesions

Adenosine deaminase complexing protein (ADCP) immunoreactivity in colorectal adenocarcinoma.

Science.gov (United States)

ten Kate, J; van den Ingh, H F; Khan, P M; Bosman, F T

1986-04-15

Immunoreactive adenosine deaminase complexing protein (ADCP) was studied in 91 human colorectal adenocarcinomas. The expression of ADCP was correlated with that of secretory component (SC) and carcinoembryonic antigen (CEA), with the histological grade and the Dukes' stage of the carcinomas. The histological grade was scored semi-quantitatively according to 5 structural and 4 cytological variables. ADCP expression was observed in 3 different staining patterns, namely: (1) diffuse cytoplasmic (77% of the carcinomas); (2) granular cytoplasmic (13%); and (3) membrane-associated (66%). These patterns were observed alone or in combination. Eleven percent of the carcinomas exhibited no ADCP immunoreactivity. Linear regression analysis showed that the expression of ADCP correlates with that of SC and CEA. However, no significant correlation emerged between the histological parameters or the Dukes' stage and any of the immunohistological parameters. Comparison of the histological characteristics of carcinomas exhibiting little or no ADCP immunoreactivity with those showing extensive immunoreactivity, showed that membranous ADCP immunoreactivity occurs more frequently in well-differentiated carcinomas. Structural parameters showed a better correlation with membranous ADCP expression than the cytological variables. It is concluded that membranous expression of ADCP and CEA are indicators of a high level of differentiation as reflected primarily in the structural characteristics of the tumor.

Interaction of Cu(+) with cytosine and formation of i-motif-like C-M(+)-C complexes: alkali versus coinage metals.

Science.gov (United States)

Gao, Juehan; Berden, Giel; Rodgers, M T; Oomens, Jos

2016-03-14

The Watson-Crick structure of DNA is among the most well-known molecular structures of our time. However, alternative base-pairing motifs are also known to occur, often depending on base sequence, pH, or the presence of cations. Pairing of cytosine (C) bases induced by the sharing of a single proton (C-H(+)-C) may give rise to the so-called i-motif, which occurs primarily in expanded trinucleotide repeats and the telomeric region of DNA, particularly at low pH. At physiological pH, silver cations were recently found to stabilize C dimers in a C-Ag(+)-C structure analogous to the hemiprotonated C-dimer. Here we use infrared ion spectroscopy in combination with density functional theory calculations at the B3LYP/6-311G+(2df,2p) level to show that copper in the 1+ oxidation state induces an analogous formation of C-Cu(+)-C structures. In contrast to protons and these transition metal ions, alkali metal ions induce a different dimer structure, where each ligand coordinates the alkali metal ion in a bidentate fashion in which the N3 and O2 atoms of both cytosine ligands coordinate to the metal ion, sacrificing hydrogen-bonding interactions between the ligands for improved chelation of the metal cation.

Ethylene emission and PR protein synthesis in ACC deaminase producing Methylobacterium spp. inoculated tomato plants (Lycopersicon esculentum Mill.) challenged with Ralstonia solanacearum under greenhouse conditions.

Science.gov (United States)

Yim, Woojong; Seshadri, Sundaram; Kim, Kiyoon; Lee, Gillseung; Sa, Tongmin

2013-06-01

Bacteria of genus Methylobacterium have been found to promote plant growth and regulate the level of ethylene in crop plants. This work is aimed to test the induction of defense responses in tomato against bacterial wilt by stress ethylene level reduction mediated by the ACC deaminase activity of Methylobacterium strains. Under greenhouse conditions, the disease index value in Methylobacterium sp. inoculated tomato plants was lower than control plants. Plants treated with Methylobacterium sp. challenge inoculated with Ralstonia solanacearum (RS) showed significantly reduced disease symptoms and lowered ethylene emission under greenhouse condition. The ACC and ACO (1-aminocyclopropane-1-carboxylate oxidase) accumulation in tomato leaves were significantly reduced with Methylobacterium strains inoculation. While ACC oxidase gene expression was found higher in plants treated with R. solanacearum than Methylobacterium sp. treatment, PR proteins related to induced systemic resistance like β-1,3-glucanase, PAL, PO and PPO were increased in Methylobacterium sp. inoculated plants. A significant increase in β-1,3-glucanase and PAL gene expression was found in all the Methylobacterium spp. treatments compared to the R. solanacearum treatment. This study confirms the activity of Methylobacterium sp. in increasing the defense enzymes by modulating the ethylene biosynthesis pathway and suggests the use of methylotrophic bacteria as potential biocontrol agents in tomato cultivation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Crystallization and preliminary X-ray crystallographic analysis of adenosine 5′-monophosphate deaminase (AMPD) from Arabidopsis thaliana in complex with coformycin 5′-phosphate

International Nuclear Information System (INIS)

Han, Byung Woo; Bingman, Craig A.; Mahnke, Donna K.; Sabina, Richard L.; Phillips, George N. Jr

2005-01-01

Adenosine 5′-monophosphate deaminase from A. thaliana has been crystallized in complex with coformycin 5′-phosphate. Diffraction data have been collected to 3.34 Å resolution. Adenosine 5′-monophosphate deaminase (AMPD) is a eukaryotic enzyme that converts adenosine 5′-monophosphate (AMP) to inosine 5′-monophosphate (IMP) and ammonia. AMPD from Arabidopsis thaliana (AtAMPD) was cloned into the baculoviral transfer vector p2Bac and co-transfected along with a modified baculoviral genome into Spodoptera frugiperda (Sf9) cells. The resulting recombinant baculovirus were plaque-purified, amplified and used to overexpress recombinant AtAMPD. Crystals of purified AtAMPD have been obtained to which coformycin 5′-phosphate, a transition-state inhibitor, is bound. Crystals belong to space group P6 2 22, with unit-cell parameters a = b = 131.325, c = 208.254 Å, α = β = 90, γ = 120°. Diffraction data were collected to 3.34 Å resolution from a crystal in complex with coformycin 5′-phosphate and to 4.05 Å resolution from a crystal of a mercury derivative

Crystallization and preliminary X-ray crystallographic analysis of adenosine 5′-monophosphate deaminase (AMPD) from Arabidopsis thaliana in complex with coformycin 5′-phosphate

Energy Technology Data Exchange (ETDEWEB)

Han, Byung Woo [Department of Biochemistry, University of Wisconsin-Madison, WI 53706-1544 (United States); Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States); Bingman, Craig A. [Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States); Mahnke, Donna K.; Sabina, Richard L. [Department of Biochemistry, The Medical College of Wisconsin, Milwaukee, WI 53226-4801 (United States); Phillips, George N. Jr, E-mail: phillips@biochem.wisc.edu [Department of Biochemistry, University of Wisconsin-Madison, WI 53706-1544 (United States); Center for Eukaryotic Structural Genomics (CESG), University of Wisconsin-Madison, WI 53706-1549 (United States)

2005-08-01

Adenosine 5′-monophosphate deaminase from A. thaliana has been crystallized in complex with coformycin 5′-phosphate. Diffraction data have been collected to 3.34 Å resolution. Adenosine 5′-monophosphate deaminase (AMPD) is a eukaryotic enzyme that converts adenosine 5′-monophosphate (AMP) to inosine 5′-monophosphate (IMP) and ammonia. AMPD from Arabidopsis thaliana (AtAMPD) was cloned into the baculoviral transfer vector p2Bac and co-transfected along with a modified baculoviral genome into Spodoptera frugiperda (Sf9) cells. The resulting recombinant baculovirus were plaque-purified, amplified and used to overexpress recombinant AtAMPD. Crystals of purified AtAMPD have been obtained to which coformycin 5′-phosphate, a transition-state inhibitor, is bound. Crystals belong to space group P6{sub 2}22, with unit-cell parameters a = b = 131.325, c = 208.254 Å, α = β = 90, γ = 120°. Diffraction data were collected to 3.34 Å resolution from a crystal in complex with coformycin 5′-phosphate and to 4.05 Å resolution from a crystal of a mercury derivative.

Serum adenosine deaminase activity and its isoenzyme in patients treated for tuberculosis

International Nuclear Information System (INIS)

Rokayan, S.A

2003-01-01

Objective: Increased serum adenosine deaminase (ADA) activity, mainly associated with tuberculosis can also occur in a number of other diseases thus negatively affecting the diagnostic utility of ADA measurements in tuberculosis. The aim of the study was to determine whether or not the combined use of the activity of ADA, its isoenzymes and differential cell counts would provide a more efficient means of diagnosing tuberculosis than the use of ADA levels alone. Results: Data suggested significant (p 0.75) of ADA/sub 2/ADA was found to be better indicator of tuberculosis. Lymphocyte neutrophil ratio (L/N)> 0.69 gave additional benefit to increase the sensitivity and specificity for the use of ADA as marker in diagnosing tuberculosis. Conclusion: The combined use of activity of ADA, its isoenzymes and total and differential cell counts is a better indicator and gives better understanding to diagnose and evaluate tuberculosis and response to therapy. (author)

AMP deaminase histochemical activity and immunofluorescent isozyme localization in rat skeletal muscle

Science.gov (United States)

Thompson, J. L.; Sabina, R. L.; Ogasawara, N.; Riley, D. A.

1992-01-01

The cellular distribution of AMP deaminase (AMPda) isozymes was documented for rat soleus and plantaris muscles, utilizing immunofluorescence microscopy and immunoprecipitation methods. AMPda is a ubiquitous enzyme existing as three distinct isozymes, A, B and C, which were initially purified from skeletal muscle, liver (and kidney), and heart, respectively. AMPda-A is primarily concentrated subsarcolemmally and intermyofibrillarly within muscle cells, while isozymes B and C are concentrated within non-myofiber elements of muscle tissue. AMPda-B is principally associated with connective tissues surrounding neural elements and the muscle spindle capsule, and AMPda-C is predominantly associated with circulatory elements, such as arterial and venous walls, capillary endothelium, and red blood cells. These specific localizations, combined with documented differences in kinetic properties, suggest multiple functional roles for the AMPda isozymes or temporal segregation of similar AMPda functions. Linkage of the AMPda substrate with adenosine production pathways at the AMP level and the localization of isozyme-C in vascular tissue suggest a regulatory role in the microcirculation.

Diagnostic value of pleural fluid adenosine deaminase activity in tuberculosis pleurisy

Directory of Open Access Journals (Sweden)

Abbas ali Niazi

2009-09-01

Full Text Available Background: Diagnosis of tuberculosis pleurisies is difficult because of its nonspecific clinical presentation and insufficient traditional diagnostic methods. We investigated the use of adenosine deaminase (ADA activity in tuberculosis pleurisies. Methods: A number of 85 patients were analyzed with exudative pleural effusions. Using the ROC curve, we determined the optimal cutoff for TB pleurisy. Results: A number of 58 exudative samples were nontuberculous (non-TB and 27 were tuberculosis (TB. There was statistically significant difference (p<0.0001 between the means of pleural fluid ADA levels among the TB and non-TB populations. The prevalence of TB pleurisy in the studied population was 31%. Using the cutoff point equal to 35 for diagnosing TB effusions the sensitivity and specificity 70.3% and 91.3%, respectively. The positive predictive value (PPV was 79.1% and the negative predictive value (NPV was 86.8%. A pleural fluid ADA value <19 IU/L suggests that a tuberculosis effusion is highly unlikely. Conclusion: Pleural fluid total ADA assay is a sensitive and specific test suitable for rapid diagnosis of TB pleurisy.

Detection of hypoxanthine, xanthine and uric acid in γ-irradiated aqueous solution of cytosine

International Nuclear Information System (INIS)

Kobayashi, Tsuya; Shirai, Kazuo

1979-01-01

The aqueous solution of cytosine of 3.6 x 10 -2 M was irradiated with gamma -ray (60 megarad) in nitrogen-saturated glass ampules, and freeze-dried, then the residue obtained was changed to trimethylsilylacid, and this was analyzed by paper chromatography, UV spectrometry, and/or gas-liquid chromatography. Hypoxanthine, xanthine and uric acid were detected in this solution, in addition to some other compounds already known to be produced by gamma -irradiation, e.g., TMS-uracil, TMS-6-hydroxyuracil and TMS-hypoxanthine. It was presumed that these compounds were formed by the recombination of the primary radiolytic products. Uric acid formation by this mechanism was confirmed by gamma -irradiation of the mixture that contained urea, and 5- and 6-hydroxyuracil. (Kaihara, S.)

Angiotensin-II type 1 receptor gene polymorphism and diabetic microangiopathy

DEFF Research Database (Denmark)

Tarnow, L; Cambien, Francois; Rossing, P

1996-01-01

with proliferative retinopathy and without diabetic retinopathy was found either: 77 (50%) / 66 (42%) / 13 (8%) vs. 42 (63%) / 22 (33%) / 3 (4%) had AA/AC/CC genotypes, respectively. CONCLUSIONS: The A1166-->C polymorphism in the angiotensin-II type 1 receptor gene does not contribute to the genetic susceptibility...... is present particularly in vascular smooth muscle cells, myocardium and the kidney. A transversion of adenine to cytosine at nucleotide position 1166 in the gene coding for the angiotensin-II type 1 receptor has been associated with hypertension in the non-diabetic population. METHODS: We studied...... the relationship between the A1166-->C polymorphism in the angiotensin-II type 1 receptor gene in patients with insulin dependent diabetes mellitus (IDDM) and diabetic nephropathy (121 men, 77 women, age 41 +/- 10 years, diabetes duration 27 +/- 8 years) and in IDDM patients with normoalbuminuria (116 men, 74...

IgG4-related Pleuritis with Elevated Adenosine Deaminase in Pleural Effusion: A Case Report.

Science.gov (United States)

Nagayasu, Atsushi; Kubo, Satoshi; Nakano, Kazuhisa; Nakayamada, Shingo; Iwata, Shigeru; Miyagawa, Ippei; Fukuyo, Shunsuke; Saito, Kazuyoshi; Tanaka, Yoshiya

2018-03-09

An 81-year-old man was admitted with bilateral pleural effusion. A clinical examination showed lymphocytic pleura effusion and elevated serum IgG4 levels, so that IgG4-related disease was suggested, whereas tuberculous pleurisy was suspected because of high adenosine deaminase (ADA) levels in the pleural effusion. A surgical pleural biopsy revealed that there were large numbers of IgG4-positive cells and IgG4/IgG positive cell ratio exceeded 40% in several sites. Accordingly, we diagnosed IgG4-related pleuritis and treated with the patient with glucocorticoid therapy. The ADA levels in pleural effusion can increase in IgG4-related pleuritis, and it is therefore important to perform a pleural biopsy.

The Role of G22 A Adenosine Deaminase 1 Gene Polymorphism and the Activities of ADA Isoenzymes in Fertile and Infertile Men.

Science.gov (United States)

Fattahi, Amir; Khodadadi, Iraj; Amiri, Iraj; Latifi, Zeinab; Ghorbani, Marzieh; Tavilani, Heidar

2015-10-01

To evaluate frequency distribution of adenosine deaminase 1 (ADA1) G22 A alleles and genotypes in fertile and infertile men. In this study we evaluate frequency distribution of ADA1 G22 A alleles and genotypes in 200 fertile and 200 infertile men. The polymerase chain reaction-restriction fragment length polymorphism technique was used for determining ADA1 G22 A variants. In addition, ADA isoenzymes activities (ADA1 and ADA2) were measured using colorimetric method. The frequency of GG genotype was significantly higher and GA genotype was lower in infertile males compared with fertile men (P = .048 and P = .045, respectively). However, there was not any noticeable difference in allele distribution between groups (P >.05). Based on logistic regression analysis, the GA genotype has a protective role and can decrease the risk of male infertility 1.7 times (P = .046). There were significantly higher activities of ADAT and its isoenzymes in infertile males compared with fertile men (P ADA1 activity with GG genotype was higher than GA carriers in all population (P = .001). Our results revealed that the activity of ADA isoenzymes and distribution of ADA1 G22 A genotypes were different among fertile and infertile men and more likely the GA genotype, which had lower ADA1 activity and was higher in fertile men is a protective factor against infertility. Copyright © 2015 Elsevier Inc. All rights reserved.

Cytidine deaminases from B. subtilis and E. coli: compensating effects of changing zinc coordination and quaternary structure.

Science.gov (United States)

Carlow, D C; Carter, C W; Mejlhede, N; Neuhard, J; Wolfenden, R

1999-09-21

Cytidine deaminase from E. coli is a dimer of identical subunits (M(r) = 31 540), each containing a single zinc atom. Cytidine deaminase from B. subtilis is a tetramer of identical subunits (M(r) = 14 800). After purification from an overexpressing strain, the enzyme from B. subtilis is found to contain a single atom of zinc per enzyme subunit by flame atomic absorption spectroscopy. Fluorescence titration indicates that each of the four subunits contains a binding site for the transition state analogue inhibitor 5-fluoro-3,4-dihydrouridine. A region of amino acid sequence homology, containing residues that are involved in zinc coordination in the enzyme from E. coli, strongly suggests that in the enzyme from B. subtilis, zinc is coordinated by the thiolate side chains of three cysteine residues (Cys-53, Cys-86, and Cys-89) [Song, B. H., and Neuhard, J. (1989) Mol. Gen. Genet. 216, 462-468]. This pattern of zinc coordination appears to be novel for a hydrolytic enzyme, and might be expected to reduce the reactivity of the active site substantially compared with that of the enzyme from E. coli (His-102, Cys-129, and Cys-132). Instead, the B. subtilis and E. coli enzymes are found to be similar in their activities, and also in their relative binding affinities for a series of structurally related inhibitors with binding affinities that span a range of 6 orders of magnitude. In addition, the apparent pK(a) value of the active site is shifted upward by less than 1 unit. Sequence alignments, together with model building, suggest one possible mechanism of compensation.

Histone H3.3 promotes IgV gene diversification by?enhancing formation of AID?accessible single?stranded DNA

OpenAIRE

Romanello, Marina; Schiavone, Davide; Frey, Alexander; Sale, Julian E

2016-01-01

Abstract Immunoglobulin diversification is driven by activation?induced deaminase (AID), which converts cytidine to uracil within the Ig variable (IgV) regions. Central to the recruitment of AID to the IgV genes are factors that regulate the generation of single?stranded DNA (ssDNA), the enzymatic substrate of AID. Here, we report that chicken DT40 cells lacking variant histone H3.3 exhibit reduced IgV sequence diversification. We show that this results from impairment of the ability of AID t...

Effect of D-valine and cytosine arabinoside on [3H]thymidine incorporation in rat and rabbit epididymal epithelial cell cultures

International Nuclear Information System (INIS)

Orgebin-Crist, M.C.; Jonas-Davies, J.; Storey, P.; Olson, G.E.

1984-01-01

Epithelial cell enriched primary cultures were established from the rat and the rabbit epididymis. Epithelial cell aggregates, obtained after pronase digestion of minced epididymis, attached to the culture dish and after 72 h in vitro spread out to form discrete patches of cells. These cells have an epithelioid morphology and form a monolayer of closely apposed polygonal cells where DNA synthesis, as judged by [ 3 H]thymidine uptake, is very low. In L-valine medium the nonepithelial cell contamination was no more than 10% in rat and rabbit epididymal primary cultures. The labeling index of rat epididymal cells cultured in D-valine medium was significantly lower than that of cells cultured in L-valine medium. In contrast, the labeling index of rabbit epididymal cells cultured in D-valine medium was significantly higher than that of cells cultured in L-valine medium. Cytosine arabinoside decreased the number of labeled cells in both L-valine and D-valine cultures. From these results, it appears that D-valine is a selective agent for rat epididymal epithelial cells, but not for rabbit epithelial cells, and that cytosine arabinoside is a simple and effective means to control the proliferation of fibroblast-like cells in both rat and rabbit epididymal cell cultures

Real time expression of ACC oxidase and PR-protein genes mediated by Methylobacterium spp. in tomato plants challenged with Xanthomonas campestris pv. vesicatoria.

Science.gov (United States)

Yim, W J; Kim, K Y; Lee, Y W; Sundaram, S P; Lee, Y; Sa, T M

2014-07-15

Biotic stress like pathogenic infection increases ethylene biosynthesis in plants and ethylene inhibitors are known to alleviate the severity of plant disease incidence. This study aimed to reduce the bacterial spot disease incidence in tomato plants caused by Xanthomonas campestris pv. vesicatoria (XCV) by modulating stress ethylene with 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity of Methylobacterium strains. Under greenhouse condition, Methylobacterium strains inoculated and pathogen challenged tomato plants had low ethylene emission compared to pathogen infected ones. ACC accumulation and ACC oxidase (ACO) activity with ACO related gene expression increased in XCV infected tomato plants over Methylobacterium strains inoculated plants. Among the Methylobacterium spp., CBMB12 resulted lowest ACO related gene expression (1.46 Normalized Fold Expression), whereas CBMB20 had high gene expression (3.42 Normalized Fold Expression) in pathogen challenged tomato. But a significant increase in ACO gene expression (7.09 Normalized Fold Expression) was observed in the bacterial pathogen infected plants. In contrast, Methylobacterium strains enhanced β-1,3-glucanase and phenylalanine ammonia-lyase (PAL) enzyme activities in pathogen challenged tomato plants. The respective increase in β-1,3-glucanase related gene expressions due to CBMB12, CBMB15, and CBMB20 strains were 66.3, 25.5 and 10.4% higher over pathogen infected plants. Similarly, PAL gene expression was high with 0.67 and 0.30 Normalized Fold Expression, in pathogen challenged tomato plants inoculated with CBMB12 and CBMB15 strains. The results suggest that ethylene is a crucial factor in bacterial spot disease incidence and that methylobacteria with ACC deaminase activity can reduce the disease severity with ultimate pathogenesis-related protein increase in tomato. Copyright © 2014 Elsevier GmbH. All rights reserved.

6-Thioguanine Reactivates Epigenetically Silenced Genes in Acute Lymphoblastic Leukemia Cells by Facilitating Proteasome-mediated Degradation of DNMT1

OpenAIRE

Yuan, Bifeng; Zhang, Jing; Wang, Hongxia; Xiong, Lei; Cai, Qian; Wang, Tina; Jacobsen, Steven; Pradhan, Sriharsa; Wang, Yinsheng

2011-01-01

Thiopurines including 6-thioguanine (SG), 6-mercaptopurine and azathioprine are effective anticancer agents with remarkable success in clinical practice, especially in effective treatment of acute lymphoblastic leukemia (ALL). SG is understood to act as a DNA hypomethylating agent in ALL cells, however, the underlying mechanism leading to global cytosine demethylation remains unclear. Here we report that SG treatment results in reactivation of epigenetically silenced genes in T leukemia cells...

Activation-induced cytidine deaminase deficiency causes organ-specific autoimmune disease.

Directory of Open Access Journals (Sweden)

Koji Hase

Full Text Available Activation-induced cytidine deaminase (AID expressed by germinal center B cells is a central regulator of somatic hypermutation (SHM and class switch recombination (CSR. Humans with AID mutations develop not only the autosomal recessive form of hyper-IgM syndrome (HIGM2 associated with B cell hyperplasia, but also autoimmune disorders by unknown mechanisms. We report here that AID-/- mice spontaneously develop tertiary lymphoid organs (TLOs in non-lymphoid tissues including the stomach at around 6 months of age. At a later stage, AID-/- mice develop a severe gastritis characterized by loss of gastric glands and epithelial hyperplasia. The disease development was not attenuated even under germ-free (GF conditions. Gastric autoantigen -specific serum IgM was elevated in AID-/- mice, and the serum levels correlated with the gastritis pathological score. Adoptive transfer experiments suggest that autoimmune CD4+ T cells mediate gastritis development as terminal effector cells. These results suggest that abnormal B-cell expansion due to AID deficiency can drive B-cell autoimmunity, and in turn promote TLO formation, which ultimately leads to the propagation of organ-specific autoimmune effector CD4+ T cells. Thus, AID plays an important role in the containment of autoimmune diseases by negative regulation of autoreactive B cells.

Rationalizing the structural variability of the exocyclic amino groups in nucleobases and their metal complexes: cytosine and adenine.

Science.gov (United States)

Fonseca Guerra, Célia; Sanz Miguel, Pablo J; Cebollada, Andrea; Bickelhaupt, F Matthias; Lippert, Bernhard

2014-07-28

The exocyclic amino groups of cytosine and adenine nucleobases are normally almost flat, with the N atoms essentially sp(2) hybridized and the lone pair largely delocalized into the heterocyclic rings. However, a change to marked pyramidality of the amino group (N then sp(3) hybridized, lone pair essentially localized at N) occurs during i) involvement of an amino proton in strong hydrogen bonding donor conditions or ii) with monofunctional metal coordination following removal of one of the two protons. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The inhibition of DNA repair by aphidicolin or cytosine arabinoside in X-irradiated normal and xeroderma pigmentosum fibroblasts

International Nuclear Information System (INIS)

Waters, R.; Crocombe, K.; Mirzayans, R.

1981-01-01

Normal and excision-deficient xeroderma pigmentosum fibroblasts were X-irradiated and the influence on DNA repair of either the repair inhibitor cytosine arabinoside or the specific inhibitor of DNA polymerase α, aphidicolin, investigated. The data indicated that the repair of a certain fraction of X-ray-induced lesions can be inhibited in both cell lines by both compounds. Thus, as aphidicolin blocks the operation of polymerase α, this enzyme must be involved in an excision repair pathway operating in both normal and excision-deficient xeroderma pigmentosum cells. (orig.)

Urtica dioica inhibits cell growth and induces apoptosis by targeting Ornithine decarboxylase and Adenosine deaminase as key regulatory enzymes in adenosine and polyamines homeostasis in human breast cancer cell lines.

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Fattahi, Sadegh; Ghadami, Elham; Asouri, Mohsen; Motevalizadeh Ardekanid, Ali; Akhavan-Niaki, Haleh

2018-02-28

Breast cancer is a heterogeneous and multifactorial disease with variable disease progression risk, and treatment response. Urtica dioica is a traditional herb used as an adjuvant therapeutic agent in cancer. In the present study, we have evaluated the effects of the aqueous extract of Urtica dioica on Adenosine deaminase (ADA) and Ornithine decarboxylase (ODC1) gene expression in MCF-7, MDA-MB-231, two breast cancer cell lines being estrogen receptor positive and estrogen receptor negative, respectively.  Cell lines were cultured in suitable media. After 24 h, different concentrations of the extract were added and after 72 h, ADA and ODC1 gene expression as well as BCL2 and BAX apoptotic genes were assessed by Taqman real time PCR assay. Cells viability was assessed by MTT assay, and apoptosis was also evaluated at cellular level. The intra and extracellular levels of ODC1 and ADA enzymes were evaluated by ELISA. Results showed differential expression of ADA and ODC1 genes in cancer cell lines. In MCF-7 cell line, the expression level of ADA was upregulated in a dose-dependent manner but its expression did not change in MDA-MB cell line. ODC1 expression was increased in both examined cell lines. Also, increased level of the apoptotic BAX/BCL-2 ratio was detected in MCF-7 cells. These results demonstrated that Urtica dioica induces apoptosis in breast cancer cells by influencing ODC1 and ADA genes expression, and estrogen receptors. The different responses observed with these cell lines could be due to the interaction of Urtica dioica as a phytoestrogen with the estrogen receptor.

Distribution of CpG Motifs in Upstream Gene Domains in a Reef Coral and Sea Anemone: Implications for Epigenetics in Cnidarians.

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Marsh, Adam G; Hoadley, Kenneth D; Warner, Mark E

2016-01-01

Coral reefs are under assault from stressors including global warming, ocean acidification, and urbanization. Knowing how these factors impact the future fate of reefs requires delineating stress responses across ecological, organismal and cellular scales. Recent advances in coral reef biology have integrated molecular processes with ecological fitness and have identified putative suites of temperature acclimation genes in a Scleractinian coral Acropora hyacinthus. We wondered what unique characteristics of these genes determined their coordinate expression in response to temperature acclimation, and whether or not other corals and cnidarians would likewise possess these features. Here, we focus on cytosine methylation as an epigenetic DNA modification that is responsive to environmental stressors. We identify common conserved patterns of cytosine-guanosine dinucleotide (CpG) motif frequencies in upstream promoter domains of different functional gene groups in two cnidarian genomes: a coral (Acropora digitifera) and an anemone (Nematostella vectensis). Our analyses show that CpG motif frequencies are prominent in the promoter domains of functional genes associated with environmental adaptation, particularly those identified in A. hyacinthus. Densities of CpG sites in upstream promoter domains near the transcriptional start site (TSS) are 1.38x higher than genomic background levels upstream of -2000 bp from the TSS. The increase in CpG usage suggests selection to allow for DNA methylation events to occur more frequently within 1 kb of the TSS. In addition, observed shifts in CpG densities among functional groups of genes suggests a potential role for epigenetic DNA methylation within promoter domains to impact functional gene expression responses in A. digitifera and N. vectensis. Identifying promoter epigenetic sequence motifs among genes within specific functional groups establishes an approach to describe integrated cellular responses to environmental stress in

Distribution of CpG Motifs in Upstream Gene Domains in a Reef Coral and Sea Anemone: Implications for Epigenetics in Cnidarians.

Directory of Open Access Journals (Sweden)

Adam G Marsh

Full Text Available Coral reefs are under assault from stressors including global warming, ocean acidification, and urbanization. Knowing how these factors impact the future fate of reefs requires delineating stress responses across ecological, organismal and cellular scales. Recent advances in coral reef biology have integrated molecular processes with ecological fitness and have identified putative suites of temperature acclimation genes in a Scleractinian coral Acropora hyacinthus. We wondered what unique characteristics of these genes determined their coordinate expression in response to temperature acclimation, and whether or not other corals and cnidarians would likewise possess these features. Here, we focus on cytosine methylation as an epigenetic DNA modification that is responsive to environmental stressors. We identify common conserved patterns of cytosine-guanosine dinucleotide (CpG motif frequencies in upstream promoter domains of different functional gene groups in two cnidarian genomes: a coral (Acropora digitifera and an anemone (Nematostella vectensis. Our analyses show that CpG motif frequencies are prominent in the promoter domains of functional genes associated with environmental adaptation, particularly those identified in A. hyacinthus. Densities of CpG sites in upstream promoter domains near the transcriptional start site (TSS are 1.38x higher than genomic background levels upstream of -2000 bp from the TSS. The increase in CpG usage suggests selection to allow for DNA methylation events to occur more frequently within 1 kb of the TSS. In addition, observed shifts in CpG densities among functional groups of genes suggests a potential role for epigenetic DNA methylation within promoter domains to impact functional gene expression responses in A. digitifera and N. vectensis. Identifying promoter epigenetic sequence motifs among genes within specific functional groups establishes an approach to describe integrated cellular responses to

p53 gene mutation hotspots in skin cancer and ultraviolet induced mutation

International Nuclear Information System (INIS)

Ikehata, Hironobu

1998-01-01

Presence of certain hotspots is known in the mutation of p53 gene in skin cancer, which are codons 177, 196, 245, 248, 278 and 282 located in the exon 5-8. In these regions, mutations like C to T and CC to TT are frequent and thereby suggest that they are resulted from pyrimidine-dimers produced by ultraviolet light (UV). In cyclobutane pyrimidine dimerization (CPD), conversion of cytosine to thymine by deamination is suggested to be the primary reaction. Although studies using UVC (254 nm) suggesting that the mutation hotspots are low repair efficiency regions could not completely explain the all hotspots, those using UVB and sunlight (UVB and UVA) revealed that CPD was efficiently produced even in such regions as not explained by studies with UVC alone. Therefore, the latter studies are conceivably reasonable since the skin cancer is induced by natural sunlight. Exon 5-8 DNA is completely methylated and the absorption coefficient of 5-methylcytosine is 5-6 times as large as that of cytosine at wavelength around 290 nm. These indicate the importance of UVB in mutation of mammalian cells possessing the ability to methylate DNA. (K.H.)

AMP Deaminase 3 Deficiency Enhanced 5′-AMP Induction of Hypometabolism

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Daniels, Isadora Susan; O′Brien, William G.; Nath, Vinay; Zhao, Zhaoyang; Lee, Cheng Chi

2013-01-01

A hypometabolic state can be induced in mice by 5′-AMP administration. Previously we proposed that an underlying mechanism for this hypometabolism is linked to reduced erythrocyte oxygen transport function due to 5′-AMP uptake altering the cellular adenylate equilibrium. To test this hypothesis, we generated mice deficient in adenosine monophosphate deaminase 3 (AMPD3), the key catabolic enzyme for 5′-AMP in erythrocytes. Mice deficient in AMPD3 maintained AMPD activities in all tissues except erythrocytes. Developmentally and morphologically, the Ampd3−/− mice were indistinguishable from their wild type siblings. The levels of ATP, ADP but not 5′-AMP in erythrocytes of Ampd3−/− mice were significantly elevated. Fasting blood glucose levels of the Ampd3−/− mice were comparable to wild type siblings. In comparison to wild type mice, the Ampd3−/− mice displayed a deeper hypometabolism with a significantly delayed average arousal time in response to 5′-AMP administration. Together, these findings demonstrate a central role of AMPD3 in the regulation of 5′-AMP mediated hypometabolism and further implicate erythrocytes in this behavioral response. PMID:24066180

Adenosine deaminase complexing protein (ADCP) expression and metastatic potential in prostatic adenocarcinomas.

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Dinjens, W N; Ten Kate, J; Kirch, J A; Tanke, H J; Van der Linden, E P; Van den Ingh, H F; Van Steenbrugge, G J; Meera Khan, P; Bosman, F T

1990-03-01

The expression of the adenosine deaminase complexing protein (ADCP) was investigated by immunohistochemistry in the normal and hyperplastic human prostate, in 30 prostatic adenocarcinomas, and in seven human prostatic adenocarcinoma cell lines grown as xenografts in athymic nude mice. In the normal and hyperplastic prostate, ADCP was localized exclusively in the apical membrane and the apical cytoplasm of the glandular epithelial cells. In prostatic adenocarcinomas, four distinct ADCP expression patterns were observed: diffuse cytoplasmic, membranous, both cytoplasmic and membranous, and no ADCP expression. The expression patterns were compared with the presence of metastases. We found an inverse correlation between membranous ADCP immunoreactivity and metastatic propensity. Exclusively membranous ADCP immunoreactivity occurred only in non-metastatic tumours. In contrast, the metastatic tumours showed no or diffuse cytoplasmic ADCP immunoreactivity. This suggests that immunohistochemical detection of ADCP might predict the biological behaviour of prostatic cancer. However, the occurrence of membranous ADCP immunoreactivity in the xenograft of a cell line (PC-EW), derived from a prostatic carcinoma metastasis, indicates that not only the tendency to metastasize modulates ADCP expression.

Targeting the Immune System to Fight Cancer Using Chemical Receptor Homing Vectors Carrying Polyinosine/Cytosine (PolyIC)

International Nuclear Information System (INIS)

Levitzki, Alexander

2012-01-01

Cancer researchers have been looking for ways to harness the immune system and to reinstate immune surveillance, to kill cancer cells without collateral damage. Here we scan current approaches to targeting the immune system against cancer, and emphasize our own approach. We are using chemical vectors attached to a specific ligand, to introduce synthetic dsRNA, polyinosine/cytosine (polyIC), into tumors. The ligand binds to a receptor protein that is overexpressed on the surface of the tumor cells. Upon ligand binding, the receptor complex is internalized, introducing the polyIC into the cell. In this fashion a large amount of synthetic dsRNA can be internalized, leading to the activation of dsRNA-binding proteins, such as dsRNA dependent protein kinase (PKR), Toll-like receptor 3 (TLR3), retinoic acid-inducible gene I (RIG-1), and melanoma differentiation-associated gene 5 (MDA5). The simultaneous activation of these signaling proteins leads to the rapid demise of the targeted cell and to cytokine secretion. The cytokines lead to a strong bystander effect and to the recruitment of immune cells that converge upon the targeted cells. The bystander effects lead to the destruction of neighboring tumor cells not targeted themselves by the vector. Normal cells, being more robust than tumor cells, survive. This strategy has several advantages: (1) recruitment of the immune system is localized to the tumor. (2) The response is rapid, leading to fast tumor eradication. (3) The bystander effects lead to the eradication of tumor cells not harboring the target. (4) The multiplicity of pro-death signaling pathways elicited by PolyIC minimizes the likelihood of the emergence of resistance. In this chapter we focus on EGFR as the targeted receptor, which is overexpressed in many tumors. In principle, the strategy can be extended to other tumors that overexpress a protein that can be internalized by a ligand, which can be a small molecule, a single chain antibody, or an affibody.

Increased activity of vascular adenosine deaminase in atherosclerosis and therapeutic potential of its inhibition.

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Kutryb-Zajac, Barbara; Mateuszuk, Lukasz; Zukowska, Paulina; Jasztal, Agnieszka; Zabielska, Magdalena A; Toczek, Marta; Jablonska, Patrycja; Zakrzewska, Agnieszka; Sitek, Barbara; Rogowski, Jan; Lango, Romuald; Slominska, Ewa M; Chlopicki, Stefan; Smolenski, Ryszard T

2016-11-01

Extracellular nucleotides and adenosine that are formed or degraded by membrane-bound ecto-enzymes could affect atherosclerosis by regulating the inflammation and thrombosis. This study aimed to evaluate a relation between ecto-enzymes that convert extracellular adenosine triphosphate to adenine dinucleotide phosphate, adenosine monophosphate, adenosine, and inosine on the surface of the vessel wall with the severity or progression of experimental and clinical atherosclerosis. Furthermore, we tested whether the inhibition of adenosine deaminase will block the development of experimental atherosclerosis. Vascular activities of ecto-nucleoside triphosphate diphosphohydrolase 1, ecto-5'-nucleotidase, and ecto-adenosine deaminase (eADA) were measured in aortas of apolipoprotein E-/- low density lipoprotein receptor (ApoE-/-LDLR-/-) and wild-type mice as well as in human aortas. Plaques were analysed in the entire aorta, aortic root, and brachiocephalic artery by Oil-Red O and Orcein Martius Scarlet Blue staining and vascular accumulation of macrophages. The cellular location of ecto-enzymes was analysed by immunofluorescence. The effect of eADA inhibition on atherosclerosis progression was studied by a 2-month deoxycoformycin treatment of ApoE-/-LDLR-/- mice. The vascular eADA activity prominently increased in ApoE-/-LDLR-/- mice when compared with wild type already at the age of 1 month and progressed along atherosclerosis development, reaching a 10-fold difference at 10 months. The activity of eADA correlated with atherosclerotic changes in human aortas. High abundance of eADA in atherosclerotic vessels originated from activated endothelial cells and macrophages. There were no changes in ecto-nucleoside triphosphate diphosphohydrolase 1 activity, whereas ecto-5'-nucleotidase was moderately decreased in ApoE-/-LDLR-/- mice. Deoxycoformycin treatment attenuated plaque development in aortic root and brachiocephalic artery of ApoE-/-LDLR-/- mice, suppressed vascular

A study of three polymorphic sites of ADA gene in colon cancer.

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Spina, C; Saccucci, P; Cozzoli, E; Bottini, E; Gloria-Bottini, F

2010-12-01

Adenosine inhibits the immune response in tumors. Adenosine deaminase (ADA) controls adenosine level and as ecto-enzyme acts as costimulatory molecule of adenosine receptors and/or CD26. We examined ADA₁, ADA₂, ADA₆ polymorphic sites of ADA gene in 109 subjects with colon cancer from Rome's population and in 246 blood donors as controls from the same population. In colon cancer ADA₁*2/ADA₂*1 haplotype is more represented, while ADA₁*2/ADA₂*2 is less represented than in controls. ADA₂*2/ADA₆*2 is less represented in patients than in controls. Polymorphic sites of ADA might influence cell-mediated anti-tumor immune responses controlling adenosine level and extraenzymatic protein functions.

Moonlighting adenosine deaminase: a target protein for drug development.

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Cortés, Antoni; Gracia, Eduard; Moreno, Estefania; Mallol, Josefa; Lluís, Carme; Canela, Enric I; Casadó, Vicent

2015-01-01

Interest in adenosine deaminase (ADA) in the context of medicine has mainly focused on its enzymatic activity. This is justified by the importance of the reaction catalyzed by ADA not only for the intracellular purine metabolism, but also for the extracellular purine metabolism as well, because of its capacity as a regulator of the concentration of extracellular adenosine that is able to activate adenosine receptors (ARs). In recent years, other important roles have been described for ADA. One of these, with special relevance in immunology, is the capacity of ADA to act as a costimulator, promoting T-cell proliferation and differentiation mainly by interacting with the differentiation cluster CD26. Another role is the ability of ADA to act as an allosteric modulator of ARs. These receptors have very general physiological implications, particularly in the neurological system where they play an important role. Thus, ADA, being a single chain protein, performs more than one function, consistent with the definition of a moonlighting protein. Although ADA has never been associated with moonlighting proteins, here we consider ADA as an example of this family of multifunctional proteins. In this review, we discuss the different roles of ADA and their pathological implications. We propose a mechanism by which some of their moonlighting functions can be coordinated. We also suggest that drugs modulating ADA properties may act as modulators of the moonlighting functions of ADA, giving them additional potential medical interest. © 2014 Wiley Periodicals, Inc.

Protection against herbivores

Energy Technology Data Exchange (ETDEWEB)

Howe, Gregg A.; Chen, Hui

2017-10-25

The present invention relates to genes, proteins and methods comprising molecules that alter amino acid levels. In one embodiment, the present invention relates to altering guanidino substrate hydrolysis activities in plants, arthropods and microorganisms using molecules within the arginase family and other molecules that alter an amino acid levels. In ones embodiment, the present invention relates to altering threonine substrate deamination and dehydration activities in plants, arthropods and microorganisms using molecules within the threonine deaminase family and other molecules that alter amino acid levels. In one embodiment, the present invention relates to using genes, proteins and methods comprising arginase or threonine deaminase for altering the pathophysiology of plants, arthropods and microorganisms. In a preferred embodiment, the present invention relates to altering guanidino substrate hydrolysis activity in plants, arthropods, and microorganisms using arginase. In another preferred embodiment, the invention relates to altering threonine substrated deamination and dehydration activity in plants, arthropods, and microorganisms using threonine deaminase. In some embodiments, the invention related to overexpression and increased activity of arginase, threonine deaminase and a proteinase inhibitor.

DNA-dependent protein kinase inhibits AID-induced antibody gene conversion.

Directory of Open Access Journals (Sweden)

Adam J L Cook

2007-04-01

Full Text Available Affinity maturation and class switching of antibodies requires activation-induced cytidine deaminase (AID-dependent hypermutation of Ig V(DJ rearrangements and Ig S regions, respectively, in activated B cells. AID deaminates deoxycytidine bases in Ig genes, converting them into deoxyuridines. In V(DJ regions, subsequent excision of the deaminated bases by uracil-DNA glycosylase, or by mismatch repair, leads to further point mutation or gene conversion, depending on the species. In Ig S regions, nicking at the abasic sites produced by AID and uracil-DNA glycosylases results in staggered double-strand breaks, whose repair by nonhomologous end joining mediates Ig class switching. We have tested whether nonhomologous end joining also plays a role in V(DJ hypermutation using chicken DT40 cells deficient for Ku70 or the DNA-dependent protein kinase catalytic subunit (DNA-PKcs. Inactivation of the Ku70 or DNA-PKcs genes in DT40 cells elevated the rate of AID-induced gene conversion as much as 5-fold. Furthermore, DNA-PKcs-deficiency appeared to reduce point mutation. The data provide strong evidence that double-strand DNA ends capable of recruiting the DNA-dependent protein kinase complex are important intermediates in Ig V gene conversion.

Ultraviolet and chemical induced DNA repair in human cells assayed by bromodeoxyuridine photolysis or cytosine arabinoside arrest

International Nuclear Information System (INIS)

Regan, J.D.; Dunn, W.C.

1979-01-01

The bromodeoxyuridine photolysis assay of DNA damage in human cells permits an estimate of both the number of repaired regions in the DNA and the size of the average repaired region - the patch size. The antineoplastic agent arabinofuranosyl cytosine (ara-C) can also be employed to assay the magnitude of repair since this agent appears to block rejoining of single-strand incisions made in the DNA during the initial step of repair. Thus, the number of incisions can be accumulated. The ara-C effect is dependent on the presence of hydroxyurea. Both assays can be employed for the study of physical or chemical DNA damages. Results comparing these assays are presented

Sequential Oral Hydroxyurea and Intravenous Cytosine Arabinoside in Refractory Childhood Acute Leukemia: A Pediatric Oncology Group Phase I Study

OpenAIRE

Dubowy, Ronald; Graham, Michael; Hakami, Nasrollah; Kletzel, Morris; Mahoney, Donald; Newman, Edward; Ravindranath, Yaddanapudi; Camitta, Bruce

2008-01-01

At concentrations >0.1 mM, Hydroxyurea (HU) enhances the accumulation of cytosine arabinoside (ara-C) in leukemia cells in vitro. This study of children with refractory acute leukemia was designed to take advantage of this biochemical modulation. A fixed dose of HU and an escalating dose of ara-C were used. Oral HU, 1200 mg/m2 was followed 2 hours later by ara-C, 250-3100 mg/m2 intravenously in 15 minutes. The combination was given on days 1,2,3 and 8,9,10. Thirty-three children (26 ALL, 7 AN...

Genetic and epigenetic alteration among three homoeologous genes of a class E MADS box gene in hexaploid wheat.

Science.gov (United States)

Shitsukawa, Naoki; Tahira, Chikako; Kassai, Ken-Ichiro; Hirabayashi, Chizuru; Shimizu, Tomoaki; Takumi, Shigeo; Mochida, Keiichi; Kawaura, Kanako; Ogihara, Yasunari; Murai, Koji

2007-06-01

Bread wheat (Triticum aestivum) is a hexaploid species with A, B, and D ancestral genomes. Most bread wheat genes are present in the genome as triplicated homoeologous genes (homoeologs) derived from the ancestral species. Here, we report that both genetic and epigenetic alterations have occurred in the homoeologs of a wheat class E MADS box gene. Two class E genes are identified in wheat, wheat SEPALLATA (WSEP) and wheat LEAFY HULL STERILE1 (WLHS1), which are homologs of Os MADS45 and Os MADS1 in rice (Oryza sativa), respectively. The three wheat homoeologs of WSEP showed similar genomic structures and expression profiles. By contrast, the three homoeologs of WLHS1 showed genetic and epigenetic alterations. The A genome WLHS1 homoeolog (WLHS1-A) had a structural alteration that contained a large novel sequence in place of the K domain sequence. A yeast two-hybrid analysis and a transgenic experiment indicated that the WLHS1-A protein had no apparent function. The B and D genome homoeologs, WLHS1-B and WLHS1-D, respectively, had an intact MADS box gene structure, but WLHS1-B was predominantly silenced by cytosine methylation. Consequently, of the three WLHS1 homoeologs, only WLHS1-D functions in hexaploid wheat. This is a situation where three homoeologs are differentially regulated by genetic and epigenetic mechanisms.

Non-linear quantitative structure-activity relationship for adenine derivatives as competitive inhibitors of adenosine deaminase

International Nuclear Information System (INIS)

Sadat Hayatshahi, Sayyed Hamed; Abdolmaleki, Parviz; Safarian, Shahrokh; Khajeh, Khosro

2005-01-01

Logistic regression and artificial neural networks have been developed as two non-linear models to establish quantitative structure-activity relationships between structural descriptors and biochemical activity of adenosine based competitive inhibitors, toward adenosine deaminase. The training set included 24 compounds with known k i values. The models were trained to solve two-class problems. Unlike the previous work in which multiple linear regression was used, the highest of positive charge on the molecules was recognized to be in close relation with their inhibition activity, while the electric charge on atom N1 of adenosine was found to be a poor descriptor. Consequently, the previously developed equation was improved and the newly formed one could predict the class of 91.66% of compounds correctly. Also optimized 2-3-1 and 3-4-1 neural networks could increase this rate to 95.83%

Feed-Forward Inhibition of CD73 and Upregulation of Adenosine Deaminase Contribute to the Loss of Adenosine Neuromodulation in Postinflammatory Ileitis

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Cátia Vieira

2014-01-01

Full Text Available Purinergic signalling is remarkably plastic during gastrointestinal inflammation. Thus, selective drugs targeting the “purinome” may be helpful for inflammatory gastrointestinal diseases. The myenteric neuromuscular transmission of healthy individuals is fine-tuned and controlled by adenosine acting on A2A excitatory receptors. Here, we investigated the neuromodulatory role of adenosine in TNBS-inflamed longitudinal muscle-myenteric plexus of the rat ileum. Seven-day postinflammation ileitis lacks adenosine neuromodulation, which may contribute to acceleration of gastrointestinal transit. The loss of adenosine neuromodulation results from deficient accumulation of the nucleoside at the myenteric synapse despite the fact that the increases in ATP release were observed. Disparity between ATP outflow and adenosine deficit in postinflammatory ileitis is ascribed to feed-forward inhibition of ecto-5′-nucleotidase/CD73 by high extracellular ATP and/or ADP. Redistribution of NTPDase2, but not of NTPDase3, from ganglion cell bodies to myenteric nerve terminals leads to preferential ADP accumulation from released ATP, thus contributing to the prolonged inhibition of muscle-bound ecto-5′-nucleotidase/CD73 and to the delay of adenosine formation at the inflamed neuromuscular synapse. On the other hand, depression of endogenous adenosine accumulation may also occur due to enhancement of adenosine deaminase activity. Both membrane-bound and soluble forms of ecto-5′-nucleotidase/CD73 and adenosine deaminase were detected in the inflamed myenteric plexus. These findings provide novel therapeutic targets for inflammatory gut motility disorders.

Fingerprints of Both Watson-Crick and Hoogsteen Isomers of the Isolated (Cytosine-Guanine)H+ Pair.

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Cruz-Ortiz, Andrés F; Rossa, Maximiliano; Berthias, Francis; Berdakin, Matías; Maitre, Philippe; Pino, Gustavo A

2017-11-16

 Gas phase protonated guanine-cytosine (CGH + ) pair was generated using an electrospray ionization source from solutions at two different pH (5.8 and 3.2). Consistent evidence from MS/MS fragmentation patterns and differential ion mobility spectra (DIMS) point toward the presence of two isomers of the CGH + pair, whose relative populations depend strongly on the pH of the solution. Gas phase infrared multiphoton dissociation (IRMPD) spectroscopy in the 900-1900 cm -1 spectral range further confirms that the Watson-Crick isomer is preferentially produced (91%) at pH = 5.8, while the Hoogsteen isomer predominates (66%) at pH = 3.2). These fingerprint signatures are expected to be useful for the development of new analytical methodologies and to trigger isomer selective photochemical studies of protonated DNA base pairs.

Preclinical evaluation of transcriptional targeting strategy for human hepatocellular carcinoma in an orthotopic xenograft mouse model.

Science.gov (United States)

Sia, Kian Chuan; Huynh, Hung; Chung, Alexander Yaw Fui; Ooi, London Lucien Peng Jin; Lim, Kiat Hon; Hui, Kam Man; Lam, Paula Yeng Po

2013-08-01

Gene regulation of many key cell-cycle players in S-, G(2) phase, and mitosis results from transcriptional repression in their respective promoter regions during the G(0) and G(1) phases of cell cycle. Within these promoter regions are phylogenetically conserved sequences known as the cell-cycle-dependent element (CDE) and cell-cycle genes homology regions (CHR) sites. Thus, we hypothesize that transcriptional regulation of cell-cycle regulation via the CDE/CHR region together with liver-specific apolipoprotein E (apoE)-hAAT promoter could bring about a selective transgene expression in proliferating human hepatocellular carcinoma. We show that the newly generated vector AH-6CC-L2C could mediate hepatocyte-targeted luciferase gene expression in tumor cells and freshly isolated short-term hepatocellular carcinoma cultures from patient biopsy. In contrast, normal murine and human hepatocytes infected with AH-6CC-L2C expressed minimal or low luciferase activities. In the presence of prodrug 5-fluorocytosine (5-FC), AH-6CC-L2C effectively suppressed the growth of orthotopic hepatocellular carcinoma patient-derived xenograft mouse model via the expression of yeast cytosine deaminase (yCD) that converts 5-FC to anticancer metabolite 5-fluoruracil. More importantly, we show that combination treatment of AH-6CC-L2C with an EZH2 inhibitor, DZNep, that targets EpCAM-positive hepatocellular carcinoma, can bring about a greater therapeutic efficacy compared with a single treatment of virus or inhibitor. Our study showed that targeting proliferating human hepatocellular carcinoma cells through the transcriptional control of therapeutic gene could represent a feasible approach against hepatocellular carcinoma.

Targeting the immune system to fight cancer using chemical receptor homing vectors carrying Poly Inosine/Cytosine (PolyIC

Directory of Open Access Journals (Sweden)

Alexander eLevitzki

2012-02-01

Full Text Available Cancer researchers have been looking for ways to harness the immune system and to reinstate immune surveillance, to kill cancer cells without collateral damage. Here we scan current approaches to targeting the immune system against cancer, and emphasize our own approach. We are using chemical vectors attached to a specific ligand, to introduce synthetic dsRNA, poly Inosine/Cytosine (polyIC, into tumors. The ligand binds to a receptor protein that is overexpressed on the surface of the tumor cells. Upon ligand binding, the receptor complex is internalized, introducing the polyIC into the cell. In this fashion a large amount of synthetic dsRNA can be internalized, leading to the activation of dsRNA binding proteins, such as dsRNA dependent protein kinase (PKR, Toll-3 receptor (TLR3, retinoic acid–inducible gene I (RIG-1 and melanoma differentiation–associated gene 5 (MDA5. The simultaneous activation of these signaling proteins leads to the rapid demise of the targeted cell and to cytokine secretion. The cytokines lead to a strong bystander effect and to the recruitment of immune cells that converge upon the targeted cells. The bystander effects lead to the destruction of neighboring tumor cells not targeted themselves by the vector. Normal cells, being more robust than tumor cells, survive. This strategy has several advantages: (1 Recruitment of the immune system is localized to the tumor. (2 The response is rapid, leading to fast tumor eradication. (3 The bystander effects lead to the eradication of tumor cells not harboring the target. (4 The multiplicity of pro-death signaling pathways elicited by PolyIC minimizes the likelihood of the emergence of resistance. In this chapter we focus on EGFR as the targeted receptor, which is overexpressed in many tumors. In principle, the strategy can be extended to other tumors that overexpress a protein that can be internalized by a ligand, which be a small molecule, a single chain antibody or an

Radiochromatographic determination of activity of adenosine deaminase and purine nucleoside phosphorylase in blood cells

International Nuclear Information System (INIS)

Pechan, I.; Rendekova, V.; Pechanova, E.; Krizko, J.

1982-01-01

Expeditious and sensitive methods are described for determining the activities of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) in human lymphocytes and erythrocytes. ADA and PNP activity is determined on the basis of the reaction of (U- 14 C)adenosine or (8- 14 C)inosine with the lysate of human blood cells. Reaction products are separated using paper chromatography. Following the measurement of the radioactivity of spots of adenosine, inosine and hypoxanthine, a calculation is made of ADA and PNP activity from the results of the said measurements. On a sample of 52 clinically healthy people average ADA and PNP activity in isolated lymphocytes was found to be (51.6+-18.8) and (185.6+-94.7) pcat/10 6 cells and in erythrocytes (9.8+-2.98) and (17.1+-3.19) pcat/mg of proteins, respectively. The advantage of the method is the small amount of sample needed (1 to 2 ml) which allows its application in pediatrics. (Ha)

The diagnostic value of procalcitonin, adenosine deaminase for tuberculous pleural effusions

International Nuclear Information System (INIS)

Sun Jia; Jing Xiufeng; Hui Fuxin

2010-01-01

Objective: To explore differential diagnostic value of procalcitonin (PCT), adenosine deaminase (ADA) in pleural fluid and serum for tuberculous pleural effusions. Methods: The concentrations of PCT and ADA both in serum and pleural fluid in one hundred and twenty-eight patients with pleural effusion were detected. These patients were divided into three groups. Fifty-two patients with tuberculous plueral effusion were composed of the tuberculous group. Twenty-two patients with parapneumonic effusion composed the pneumonic group and forty patients with malignant pleural effusion and fourteen patients with heart faliure composed of the control group. Results: There were no statistically significant differences in serum PCT among the three groups (P > 0.05). PCT of pleural fluid was significantly increased in tuberculous and parapneumonic groups compared to the control group (P < 0.05). ADA activities in tuberculous serum and pleural fluid were both higher than those in the parapneumonic and the control groups (P < 0.01). The ratio of ADA in pleural fluid and serum (P /S) was calculated. The diagnostic sensitivity and specificity of P /S (cut-off value 1.27) were 92.3% and 100% respectively for tuberculous pleural effusions calcuted by receiver operating curve. Conclusion: Combined measurements of PCT and ADA in pleural fluid are useful in diagnosing tuberculous pleural effusions. (authors)

Lack of association of the G22A polymorphism of the ADA gene in patients with ankylosing spondylitis.

Science.gov (United States)

Camargo, U; Toledo, R A; Cintra, J R; Nunes, D P T; Acayaba de Toledo, R; Brandão de Mattos, C C; Mattos, L C

2012-05-07

Genes located outside the HLA region (6p21) have been considered as candidates for susceptibility to ankylosing spondylitis. We tested the hypothesis that the G22A polymorphism of the adenosine deaminase gene (ADA; 20q13.11) is associated with ankylosing spondylitis in 166 Brazilian subjects genotyped for the HLA*27 gene (47 patients and 119 controls matched for gender, age and geographic origin). The HLA-B*27 gene and the G22A ADA polymorphism were identified by PCR with sequence-specific oligonucleotide probes and PCR-RFLP, respectively. There were no significant differences in frequencies of ADA genotypes [odds ratio (OR) = 1.200, 95% confidence interval (CI) = 0.3102-4.643, P > 0.8] and ADA*01 and ADA*02 alleles (OR = 1.192, 95%CI = 0.3155-4.505, P > 0.8) in patients versus controls. We conclude that the G22A polymorphism is not associated with ankylosing spondylitis.

Role of Glutamate 64 in the Activation of the Prodrug 5-Fluorocytosine by Yeast Cytosine Deaminase

Czech Academy of Sciences Publication Activity Database

Wang, J.; Sklenák, Štěpán; Liu, A.; Felczak, K.; Wu, Y.; Li, Y.; Yan, H.

2012-01-01

Roč. 51, č. 1 (2012), s. 475-486 ISSN 0006-2960 R&D Projects: GA AV ČR IAA400400812; GA AV ČR IAA400400908; GA ČR GA203/09/1627 Institutional research plan: CEZ:AV0Z40400503 Keywords : transition-state analog * barrier hydrogen-bond * side-chain amides Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.377, year: 2012

Regulation of adenosine deaminase (ADA) on induced mouse experimental autoimmune uveitis (EAU) ‡

Science.gov (United States)

Liang, Dongchun; Zuo, Aijun; Zhao, Ronglan; Shao, Hui; Kaplan, Henry J.; Sun, Deming

2016-01-01

Adenosine is an important regulator of the immune response and adenosine deaminase (ADA) inhibits this regulatory effect by converting adenosine into functionally inactive molecules. Studies have shown that adenosine receptor (AR) agonists can be either anti- or pro-inflammatory. Clarification of the mechanisms that cause these opposing effects should provide a better guide for therapeutic intervention. In this study, we investigated the effect of ADA on the development of experimental autoimmune uveitis (EAU) induced by immunizing EAU-prone mice with a known uveitogenic peptide, IRBP1–20. Our results showed that the effective time to administer a single dose of ADA to suppress induction of EAU was 8–14 days post-immunization, shortly before EAU expression, but ADA treatment at other time points exacerbated disease. ADA preferentially inhibited Th17 responses and this effect was γδ T cell-dependent. Our results demonstrated that the existing immune status strongly influences the anti- or proinflammatory effects of ADA. Our observations should help improve the design of ADA- and AR-targeted therapies. PMID:26856700

Effect of repeated pesticide applications on soil properties in cotton fields: II. Insecticide residues and impact on dehydrogenase and arginine deaminase activities

International Nuclear Information System (INIS)

Vig, K.; Singh, D.K.; Agarwal, H.C.; Dhawan, A.K.; Dureja, P.

2001-01-01

Insecticides were applied sequentially at recommended dosages post crop emergence in cotton fields and soil was sampled at regular intervals after each treatment. Soil was analysed for insecticide residues and activity of the enzymes dehydrogenase and arginine deaminase. Insecticide residues detected in the soil were in small quantities and they did not persist for long. Only endosulfan leached below 15 cm. Insecticides had only temporary effects on enzyme activities which disappeared either before the next insecticide treatment or by the end of the experimental period. (author)

δ-crystallin genes become hypomethylated in postmitotic lens cells during chicken development

International Nuclear Information System (INIS)

Sullivan, C.H.; Grainger, R.M.

1987-01-01

Although it has been argued that the loss of 5-methylcytosine from specific sites in DNA plays an important role in activation of specific genes, the mechanism of hypomethylation is not well understood. One model links the process to DNA replication, proposing that it occurs by not remethylating cytosine on newly synthesized DNA. An alternative model argues that hypomethylation results from excision of part or all of the 5-methylcytosine. The authors were able to test whether hypomethylation can occur without replication by analysis of methylation changes in the δ-crystallin genes of the chicken lens. During embryonic development a large fraction of cells in the lens stops dividing as part of the differentiation process, measured by autoradiography. Shortly after this stage, the δ-crystallin genes in samples of the whole lens become hypomethylated, suggesting the possibility that this process might be occurring in the subset of cells that is no longer dividing. They found that hypomethylation of these genes does occur in postmitotic lens cells, a result that implicates an excision mechanism in this tissue

TET1-Mediated Hydroxymethylation Facilitates Hypoxic Gene Induction in Neuroblastoma

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Christopher J. Mariani

2014-06-01

Full Text Available The ten-eleven-translocation 5-methylcytosine dioxygenase (TET family of enzymes catalyzes the conversion of 5-methylcytosine (5-mC to 5-hydroxymethylcytosine (5-hmC, a modified cytosine base that facilitates gene expression. Cells respond to hypoxia by inducing a transcriptional program regulated in part by oxygen-dependent dioxygenases that require Fe(II and α-ketoglutarate. Given that the TET enzymes also require these cofactors, we hypothesized that the TETs regulate the hypoxia-induced transcriptional program. Here, we demonstrate that hypoxia increases global 5-hmC levels, with accumulation of 5-hmC density at canonical hypoxia response genes. A subset of 5-hmC gains colocalize with hypoxia response elements facilitating DNA demethylation and HIF binding. Hypoxia results in transcriptional activation of TET1, and full induction of hypoxia-responsive genes and global 5-hmC increases require TET1. Finally, we show that 5-hmC increases and TET1 upregulation in hypoxia are HIF-1 dependent. These findings establish TET1-mediated 5-hmC changes as an important epigenetic component of the hypoxic response.

Prolonged pancytopenia in a gene therapy patient with ADA-deficient SCID and trisomy 8 mosaicism: a case report.

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Engel, Barbara C; Podsakoff, Greg M; Ireland, Joanna L; Smogorzewska, E Monika; Carbonaro, Denise A; Wilson, Kathy; Shah, Ami; Kapoor, Neena; Sweeney, Mirna; Borchert, Mark; Crooks, Gay M; Weinberg, Kenneth I; Parkman, Robertson; Rosenblatt, Howard M; Wu, Shi-Qi; Hershfield, Michael S; Candotti, Fabio; Kohn, Donald B

2007-01-15

A patient with adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID) was enrolled in a study of retroviral-mediated ADA gene transfer to bone marrow hematopoietic stem cells. After the discontinuation of ADA enzyme replacement, busulfan (75 mg/m2) was administered for bone marrow cytoreduction, followed by infusion of autologous, gene-modified CD34+ cells. The expected myelosuppression developed after busulfan but then persisted, necessitating the administration of untransduced autologous bone marrow back-up at day 40. Because of sustained pancytopenia and negligible gene marking, diagnostic bone marrow biopsy and aspirate were performed at day 88. Analyses revealed hypocellular marrow and, unexpectedly, evidence of trisomy 8 in 21.6% of cells. Trisomy 8 mosaicism (T8M) was subsequently diagnosed by retrospective analysis of a pretreatment marrow sample that might have caused the lack of hematopoietic reconstitution. The confounding effects of this preexisting marrow cytogenetic abnormality on the response to gene transfer highlights another challenge of gene therapy with the use of autologous hematopoietic stem cells.

A2A adenosine receptor ligand binding and signalling is allosterically modulated by adenosine deaminase.

Science.gov (United States)

Gracia, Eduard; Pérez-Capote, Kamil; Moreno, Estefanía; Barkešová, Jana; Mallol, Josefa; Lluís, Carme; Franco, Rafael; Cortés, Antoni; Casadó, Vicent; Canela, Enric I

2011-05-01

A2ARs (adenosine A2A receptors) are highly enriched in the striatum, which is the main motor control CNS (central nervous system) area. BRET (bioluminescence resonance energy transfer) assays showed that A2AR homomers may act as cell-surface ADA (adenosine deaminase; EC 3.5.4.4)-binding proteins. ADA binding affected the quaternary structure of A2ARs present on the cell surface. ADA binding to adenosine A2ARs increased both agonist and antagonist affinity on ligand binding to striatal membranes where these proteins are co-expressed. ADA also increased receptor-mediated ERK1/2 (extracellular-signal-regulated kinase 1/2) phosphorylation. Collectively, the results of the present study show that ADA, apart from regulating the concentration of extracellular adenosine, may behave as an allosteric modulator that markedly enhances ligand affinity and receptor function. This powerful regulation may have implications for the physiology and pharmacology of neuronal A2ARs.

Raised Serum Adenosine Deaminase Level in Nonobese Type 2 Diabetes Mellitus

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Vineet Kumar Khemka

2013-01-01

Full Text Available The role of inflammation being minimal in the pathogenesis of type 2 diabetes mellitus (T2DM in nonobese patients; the aim of the study was to investigate the role of adenosine deaminase (ADA and see its association with diabetes mellitus. The preliminary case control study comprised of 56 cases and 45 healthy controls which were age and sex matched. 3 mL venous blood samples were obtained from the patients as well as controls after 8–10 hours of fasting. Serum ADA and routine biochemical parameters were analyzed. Serum ADA level was found significantly higher among nonobese T2DM subjects with respect to controls (38.77±14.29 versus 17.02±5.74 U/L; P<0.0001. Serum ADA level showed a significant positive correlation with fasting plasma glucose (r=0.657; P<0.0001 level among nonobese T2DM subjects, but no significant correlation was observed in controls (r=-0.203; P=0.180. However, no correlation was observed between serum ADA level compared to BMI and HbA1c levels. Our study shows higher serum ADA, triglycerides (TG and fasting plasma glucose (FPG levels in nonobese T2DM patients, and a strong correlation between ADA and FPG which suggests an association between ADA and nonobese T2DM subjects.

Assessment of adenosine deaminase (ADA) activity and oxidative stress in patients with chronic tonsillitis.

Science.gov (United States)

Garca, Mehmet Fatih; Demir, Halit; Turan, Mahfuz; Bozan, Nazım; Kozan, Ahmet; Belli, Şeyda Bayel; Arslan, Ayşe; Cankaya, Hakan

2014-06-01

To emphasize the effectiveness of adenosine deaminase (ADA) enzyme, which has important roles in the differentiation of lymphoid cells, and oxidative stress in patients with chronic tonsillitis. Serum and tissue samples were obtained from 25 patients who underwent tonsillectomy due to recurrent episodes of acute tonsillitis. In the control group, which also had 25 subjects, only serum samples were taken as obtaining tissue samples would not have been ethically appropriate. ADA enzyme activity, catalase (CAT), carbonic anhydrase (CA), nitric oxide (NO) and malondialdehyde (MDA) were measured in the serum and tissue samples of patients and control group subjects. The serum values of both groups were compared. In addition, the tissue and serum values of patients were compared. Serum ADA activity and the oxidant enzymes MDA and NO values of the patient group were significantly higher than those of the control group (p ADA activity (p > 0.05). Elevated ADA activity may be effective in the pathogenesis of chronic tonsillitis both by impairing tissue structure and contributing to SOR formation.

Diagnostic value of adenosine deaminase in ascites for tuberculosis ascites: a meta-analysis.

Science.gov (United States)

Tao, Lin; Ning, Hong-Jian; Nie, Hai-Ming; Guo, Xiao-Yun; Qin, Shan-Yu; Jiang, Hai-Xing

2014-05-01

The diagnosis of tuberculosis (TB) ascites using standard diagnostic tools is difficult. The aim of the present meta-analysis was to establish the overall diagnostic accuracy of adenosine deaminase (ADA) levels in ascites for diagnosing TB ascites. A systematic review was performed of English language publications prior to April 2013. Sensitivity, specificity, and other measures of the accuracy of ADA for the diagnosis of TB ascites using ascites fluid were summarized using a random-effects model or a fixed-effects model. Receiver operating characteristic curves were used to summarize overall test performance. Seventeen studies involving 1797 subjects were eligible for the analysis. The summary estimates of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under cure of overall analysis were: 0.93, 0.94, 13.55, 0.11, 169.83, and 0.976, respectively; the results of sensitivity analysis of studies that used Giusti method were 0.94, 0.94, 12.99, 0.08, 183.18, and 0.977, respectively. Our results suggest that ADA in the ascites can be a sensitive and specific target and a critical criterion for the diagnosis of TB ascites. Copyright © 2014 Elsevier Inc. All rights reserved.

Investigations into the origin of the molecular recognition of several adenosine deaminase inhibitors.

Science.gov (United States)

Gillerman, Irina; Fischer, Bilha

2011-01-13

Inhibitors of adenosine deaminase (ADA, EC 3.5.4.4) are potential therapeutic agents for the treatment of various health disorders. Several highly potent inhibitors were previously identified, yet they exhibit unacceptable toxicities. We performed a SAR study involving a series of C2 or C8 substituted purine-riboside analogues with a view to discover less potent inhibitors with a lesser toxicity. We found that any substitution at C8 position of nebularine resulted in total loss of activity toward calf intestinal ADA. However, several 2-substituted-adenosine, 8-aza-adenosine, and nebularine analogues exhibited inhibitory activity. Specifically, 2-Cl-purine riboside, 8-aza-2-thiohexyl adenosine, 2-thiohexyl adenosine, and 2-MeS-purine riboside were found to be competitive inhibitors of ADA with K(i) values of 25, 22, 6, and 3 μM, respectively. We concluded that electronic parameters are not major recognition determinants of ADA but rather steric parameters. A C2 substituent which fits ADA hydrophobic pocket and improves H-bonding with the enzyme makes a good inhibitor. In addition, a gg rotamer about C4'-C5' bond is apparently an important recognition determinant.

Increased Number of Circulating CD8/CD26 T Cells in the Blood of Duchenne Muscular Dystrophy Patients Is Associated with Augmented Binding of Adenosine Deaminase and Higher Muscular Strength Scores

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Jonathan H. Soslow

2017-12-01

Full Text Available Duchenne muscular dystrophy (DMD is an X-linked disorder that leads to cardiac and skeletal myopathy. The complex immune activation in boys with DMD is incompletely understood. To better understand the contribution of the immune system into the progression of DMD, we performed a systematic characterization of immune cell subpopulations obtained from peripheral blood of DMD subjects and control donors. We found that the number of CD8 cells expressing CD26 (also known as adenosine deaminase complexing protein 2 was increased in DMD subjects compared to control. No differences, however, were found in the levels of circulating factors associated with pro-inflammatory activation of CD8/CD26 cells, such as tumor necrosis factor-α (TNFα, granzyme B, and interferon-γ (IFNγ. The number of CD8/CD26 cells correlated directly with quantitative muscle testing (QMT in DMD subjects. Since CD26 mediates binding of adenosine deaminase (ADA to the T cell surface, we tested ADA-binding capacity of CD8/CD26 cells and the activity of bound ADA. We found that mononuclear cells (MNC obtained from DMD subjects with an increased number of CD8/CD26 T cells had a greater capacity to bind ADA. In addition, these MNC demonstrated increased hydrolytic deamination of adenosine to inosine. Altogether, our data demonstrated that (1 an increased number of circulating CD8/CD26 T cells is associated with preservation of muscle strength in DMD subjects, and (2 CD8/CD26 T cells from DMD subjects mediated degradation of adenosine by adenosine deaminase. These results support a role for T cells in slowing the decline in skeletal muscle function, and a need for further investigation into contribution of CD8/CD26 T cells in the regulation of chronic inflammation associated with DMD.

Spectroscopic (UV/VIS, Raman) and Electrophoresis Study of Cytosine-Guanine Oligonucleotide DNA Influenced by Magnetic Field.

Science.gov (United States)

Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Boon Tong, Goh; Abdul Rahman, Saadah

2016-01-01

Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100), is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT). As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.

Efficacy and toxicity of replication-competent adenovirus-mediated double suicide gene therapy in combination with radiation therapy in an orthotopic mouse prostate cancer model

International Nuclear Information System (INIS)

Freytag, Svend O.; Paielli, Dell; Wing, Mark; Rogulski, Ken; Brown, Steve; Kolozsvary, Andy; Seely, John; Barton, Ken; Dragovic, Alek; Kim, Jae Ho

2002-01-01

Purpose: The purpose of this study was to evaluate the efficacy and toxicity of replication-competent adenovirus-mediated double suicide gene therapy in an adjuvant setting with external beam radiation therapy (EBRT) in an experimental prostate cancer model in preparation for a Phase I clinical study in humans. Methods: For efficacy studies, i.m. DU145 and intraprostatic LNCaP C4-2 tumors were established in immune-deficient mice. Tumors were injected with the lytic, replication-competent Ad5-CD/TKrep adenovirus containing a cytosine deaminase (CD)/herpes simplex virus thymidine kinase (HSV-1 TK) fusion gene. Two days later, mice were administered 1 week of 5-fluorocytosine + ganciclovir (GCV) prodrug therapy and fractionated doses of EBRT (trimodal therapy). Tumor control rate of trimodal therapy was compared to that of EBRT alone. For toxicology studies, immune-competent male mice received a single intraprostatic injection (10 10 vp) of the replication-competent Ad5-CD/TKrep adenovirus. Two days later, mice were administered 4 weeks of 5-fluorocytosine + GCV prodrug therapy and 56 Gy EBRT to the pelvic region. The toxicity of trimodal therapy was assessed by histopathologic analysis of major organs and clinical chemistries. Results: In both the i.m. DU145 and intraprostatic LNCaP C4-2 tumor models, trimodal therapy significantly improved primary tumor control beyond that of EBRT alone. In the DU145 model, trimodal therapy resulted in a tumor growth delay (70 days) that was more than twice that (32 days) of EBRT alone. Whereas EBRT failed to eradicate DU145 tumors, trimodal therapy resulted in 25% tumor cure. In the LNCaP C4-2 tumor model, EBRT slowed the growth of intraprostatic tumors, but resulted in no tumor cures, and 57% of the mice developed retroperitoneal lymph node metastases at 3 months. By contrast, trimodal therapy resulted in 44% tumor cure and reduced significantly the percentage (13%) of lymph node metastases relative to EBRT alone. Overall

X-ray structure of imidazolonepropionase from Agrobacterium tumefaciens at 1.87 Å resolution

Energy Technology Data Exchange (ETDEWEB)

Tyagi, Rajiv; Kumaran, Desigan; Burley, Stephen K.; Swaminathan, Subramanyam (SGX); (BNL)

2010-01-12

Histidine degradation in Agrobacterium tumefaciens involves four enzymes, including histidase (EC 4.3.1.3), urocanase (EC 4.2.1.49), imidazolonepropionase (EC 3.5.2.7), and N-formylglutamate amidohydrolase (EC 3.5.3.8). The third enzyme of the pathway, imidazolone-propionase, a 45.6 kDa protein, catalyzes conversion of imidazolone-5-propanoate to N-forminio-L-glutamate. Initial studies of the role of imidazolonepropionase in histidine degradation were published in 1953. Subsequent publications have been limited to enzyme kinetics, crystallization, and a recently reported structure determination. The imidazolonepropionases are members of metallodepenent-hydrolases (or amidohydroase) superfamily, which includs ureases, adenosine deaminases, phosphotriesterases, dihydroorotases, allantoinases, hydantoinases, adenine and cytosine deaminases, imidazolonepropionases, aryldial-kylphosphatases, chlorohydrolases, and formylmethanofuran dehydroases. Proteins belonging to this large group share a common three-dimensional structural motif (an eightfold {alpha}/{beta} or TIM barrel) with similar active sites. Most superfamily members also share a conserved metal binding site, involving four histidine residues and one aspartic acid. Imidazolonepropionase is one of the targets selected for X-ray crystallpgrahpic structure determination by the New York Structural GenomiX Research Consortium (NYSGXRC) Target ID: 9252b to correlate the structure function relationship of poorly studied by important enzyme. Here they report the crystal structure of imidazolonepropionase from Agrobacterium tumefaciens determined at 1.87 {angstrom} resolution.

Water-mediated tautomerization of cytosine to the rare imino form: An ab initio dynamics study

Energy Technology Data Exchange (ETDEWEB)

Fogarasi, Geza [Institute of Chemistry, Eotvos University, H-1518 Budapest, Pf. 32. (Hungary)], E-mail: fg@chem.elte.hu

2008-06-16

Tautomerism in nucleotide bases is one of the possible mechanisms of mutation of DNA. In spite of numerous studies on the structure and energy of cytosine tautomers, little information is available on the process of proton transfer itself. We present here Born-Oppenheimer dynamics calculations, with the potential surface obtained 'on the fly' from ab initio quantum chemistry (QC) and the atoms moving classically. In search for water-mediated tautomerization the monohydrated complex was studied, running about 300 trajectories each of 3000-5000 points of 1 fs steps. One single trajectory has been found to lead to tautomerization. Although the QC method used in the simulations was inevitably modest (B3LYP/3-21G), higher-level test calculations along the same trajectory suggest that the simulation grasped the basic mechanism of proton transfer: a concerted, synchronous process characterized by strong coupling between the motions of the two participating hydrogen atoms.

Molecular Analysis of Activation-Induced Cytidine Deaminase Gene in Immunoglobulin-E Deficient Patients

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Sergio Roa

2008-01-01

Full Text Available Understanding how class switch recombination (CSR is regulated to produce immunoglobulin E (IgE has become fundamental because of the dramatic increase in the prevalence of IgE-mediated hypersensitivity reactions. CSR requires the induction of the enzyme AICDA in B cells. Mutations in AICDA have been linked to Hyper-IgM syndrome (HIGM2, which shows absence of switching to IgE as well as to IgG and IgA. Although isolated IgE deficiency is a rare entity, here we show some individuals with normal serum IgM, IgG, and IgA levels that had undetectable total serum IgE levels. We have analyzed the AICDA gene in these individuals to determine if there are mutations in AICDA that could lead to selective IgE deficiency. Conformational sensitive gel electrophoresis (CSGE and sequencing analysis of AICDA coding sequences demonstrated sequence heterogeneity due to 5923A/G and 7888C/T polymorphisms, but did not reveal any novel mutation that might explain the selective IgE deficit.

Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

Energy Technology Data Exchange (ETDEWEB)

Yang, Yingbin [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); School of Life Science, Southwest University, Chongqing 400715 (China); Cai, Shaoxi, E-mail: sxcai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Yang, Li [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); College of Pharmacy, Jinan University, Guangzhou 510632 (China); Yu, Shuhui [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Library of Southwest University, Chongqing 400715 (China); Jiang, Jiahuan; Yan, Xiaoqing [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Zhang, Haoxing [School of Life Science, Southwest University, Chongqing 400715 (China); Liu, Lan [Department of Laboratory of Medicine, Children' s Hospital of Chongqin Medical University, Chongqing 400014 (China); Liu, Qun [College of Life Science and Technology, Southwest University for Nationalities, Chengdu 610041 (China); Du, Jun [Center of Microbiology, Biochemistry, and Pharmacology, School of Pharmaceutical Science, Sun Yat-Sen University, Guangzhou 510080 (China); Cai, Shaohui [College of Pharmacy, Jinan University, Guangzhou 510632 (China); Sung, K.L. Paul [Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044 (China); Departments of Orthopaedic Surgery and Bioengineering, University of California, SD 0412 (United States)

2010-12-10

Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells

International Nuclear Information System (INIS)

Yang, Yingbin; Cai, Shaoxi; Yang, Li; Yu, Shuhui; Jiang, Jiahuan; Yan, Xiaoqing; Zhang, Haoxing; Liu, Lan; Liu, Qun; Du, Jun; Cai, Shaohui; Sung, K.L. Paul

2010-01-01

Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

Comparative analysis of codon usage patterns and identification of predicted highly expressed genes in five Salmonella genomes

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Mondal U

2008-01-01

Full Text Available Purpose: To anlyse codon usage patterns of five complete genomes of Salmonella , predict highly expressed genes, examine horizontally transferred pathogenicity-related genes to detect their presence in the strains, and scrutinize the nature of highly expressed genes to infer upon their lifestyle. Methods: Protein coding genes, ribosomal protein genes, and pathogenicity-related genes were analysed with Codon W and CAI (codon adaptation index Calculator. Results: Translational efficiency plays a role in codon usage variation in Salmonella genes. Low bias was noticed in most of the genes. GC3 (guanine cytosine at third position composition does not influence codon usage variation in the genes of these Salmonella strains. Among the cluster of orthologous groups (COGs, translation, ribosomal structure biogenesis [J], and energy production and conversion [C] contained the highest number of potentially highly expressed (PHX genes. Correspondence analysis reveals the conserved nature of the genes. Highly expressed genes were detected. Conclusions: Selection for translational efficiency is the major source of variation of codon usage in the genes of Salmonella . Evolution of pathogenicity-related genes as a unit suggests their ability to infect and exist as a pathogen. Presence of a lot of PHX genes in the information and storage-processing category of COGs indicated their lifestyle and revealed that they were not subjected to genome reduction.

Spectroscopic (UV/VIS, Raman and Electrophoresis Study of Cytosine-Guanine Oligonucleotide DNA Influenced by Magnetic Field.

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Seyedeh Maryam Banihashemian

Full Text Available Studying the effect of a magnetic field on oligonucleotide DNA can provide a novel DNA manipulation technique for potential application in bioengineering and medicine. In this work, the optical and electrochemical response of a 100 bases oligonucleotides DNA, cytosine-guanine (CG100, is investigated via exposure to different magnetic fields (250, 500, 750, and 1000 mT. As a result of the optical response of CG100 to the magnetic field, the ultra-violet-visible spectrum indicated a slight variation in the band gap of CG100 of about 0.3 eV. Raman spectroscopy showed a significant deviation in hydrogen and phosphate bonds' vibration after exposure to the magnetic field. Oligonucleotide DNA mobility was investigated in the external electric field using the gel electrophoresis technique, which revealed a small decrease in the migration of CG100 after exposure to the magnetic field.

Gene therapy for adenosine deaminase–deficient severe combined immune deficiency: clinical comparison of retroviral vectors and treatment plans

Science.gov (United States)

Candotti, Fabio; Shaw, Kit L.; Muul, Linda; Carbonaro, Denise; Sokolic, Robert; Choi, Christopher; Schurman, Shepherd H.; Garabedian, Elizabeth; Kesserwan, Chimene; Jagadeesh, G. Jayashree; Fu, Pei-Yu; Gschweng, Eric; Cooper, Aaron; Tisdale, John F.; Weinberg, Kenneth I.; Crooks, Gay M.; Kapoor, Neena; Shah, Ami; Abdel-Azim, Hisham; Yu, Xiao-Jin; Smogorzewska, Monika; Wayne, Alan S.; Rosenblatt, Howard M.; Davis, Carla M.; Hanson, Celine; Rishi, Radha G.; Wang, Xiaoyan; Gjertson, David; Yang, Otto O.; Balamurugan, Arumugam; Bauer, Gerhard; Ireland, Joanna A.; Engel, Barbara C.; Podsakoff, Gregory M.; Hershfield, Michael S.; Blaese, R. Michael; Parkman, Robertson

2012-01-01

We conducted a gene therapy trial in 10 patients with adenosine deaminase (ADA)–deficient severe combined immunodeficiency using 2 slightly different retroviral vectors for the transduction of patients' bone marrow CD34+ cells. Four subjects were treated without pretransplantation cytoreduction and remained on ADA enzyme-replacement therapy (ERT) throughout the procedure. Only transient (months), low-level (< 0.01%) gene marking was observed in PBMCs of 2 older subjects (15 and 20 years of age), whereas some gene marking of PBMC has persisted for the past 9 years in 2 younger subjects (4 and 6 years). Six additional subjects were treated using the same gene transfer protocol, but after withdrawal of ERT and administration of low-dose busulfan (65-90 mg/m2). Three of these remain well, off ERT (5, 4, and 3 years postprocedure), with gene marking in PBMC of 1%-10%, and ADA enzyme expression in PBMC near or in the normal range. Two subjects were restarted on ERT because of poor gene marking and immune recovery, and one had a subsequent allogeneic hematopoietic stem cell transplantation. These studies directly demonstrate the importance of providing nonmyeloablative pretransplantation conditioning to achieve therapeutic benefits with gene therapy for ADA-deficient severe combined immunodeficiency. PMID:22968453

Diagnostic Utility of Pleural Fluid Adenosine Deaminase Level in Tuberculousis Pleural Effusion

International Nuclear Information System (INIS)

Suleman, A.; Abbasi, M. A.; Anwar, S. A.; Kamal, M.; Khan, H.

2016-01-01

Background: Early diagnosis and management of tuberculosis is essential for decreasing the disease burden. Pakistan is one of the few countries of world with a very high burden of tuberculosis. Many diagnostic tests are available for detection of tuberculosis but each is fraught with certain limitations of its own. Methods: This study was a cross sectional validation study that sought to determine the validity of pleural fluid adenosine deaminase levels for diagnosis of tuberculous pleural effusion. Results: A total of 160 patients with exudative lymphocytic pleural effusions were enrolled in this study. The mean pleural fluid ADA level was 52.18±1.98 U/L. The mean pleural fluid ADA level in patients diagnosed to have tuberculosis on pleural biopsy/histopathology was higher as compared to patients who did not have tuberculous pleural effusion 52.16±2.4 U/L vs 38.6±3.14 U/L. The difference was found to be statistically significant between the two groups (p<0.05). The sensitivity, specificity, ppv and npv of pleural fluid ADA level were 88.88 percent, 77.04 percent, 86.28 percent and 81.04 percent respectively. Conclusion: Despite wide variations in the reported sensitivity and specificity of pleural fluid ADA level, it can be used as a surrogate for pleural biopsy when the latter is not feasible. (author)

Identification of a Novel Methylated Gene in Nasopharyngeal Carcinoma: TTC40

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Wajdi Ayadi

2014-01-01

Full Text Available To further explore the epigenetic changes in nasopharyngeal carcinoma (NPC, methylation-sensitive arbitrarily primed PCR was performed on NPC biopsies and nontumor nasopharyngeal samples. We have shown mainly two DNA fragments that appeared to be differentially methylated in NPCs versus nontumors. The first, defined as hypermethylated, corresponds to a CpG island at the 5′-end of the tetratricopeptide repeat domain 40 (TTC40 gene, whereas the second, defined as hypo-methylated, is located on repetitive sequences at chromosomes 16p11.1 and 13.1. Thereafter, the epigenetic alteration on the 5′-TTC40 gene was confirmed by methylation-specific PCR, showing a significant aberrant methylation in NPCs, compared to nontumors. In addition, the bisulfite sequencing analysis has shown a very high density of methylated cytosines in C15, C17, and X666 NPC xenografts. To assess whether TTC40 gene is silenced by aberrant methylation, we examined the gene expression by reverse transcription-PCR. Our analysis showed that the mRNA expression was significantly lower in tumors than in nontumors, which is associated with 5′-TTC40 gene hypermethylation. In conclusion, we found that the 5′-TTC40 gene is frequently methylated and is associated with the loss of mRNA expression in NPCs. Hypermethylation of 5′-TTC40 gene might play a role in NPC development; nevertheless, other studies are needed.

Basic and clinical immunology

Science.gov (United States)

Chinen, Javier; Shearer, William T.

2003-01-01

Progress in immunology continues to grow exponentially every year. New applications of this knowledge are being developed for a broad range of clinical conditions. Conversely, the study of primary and secondary immunodeficiencies is helping to elucidate the intricate mechanisms of the immune system. We have selected a few of the most significant contributions to the fields of basic and clinical immunology published between October 2001 and October 2002. Our choice of topics in basic immunology included the description of T-bet as a determinant factor for T(H)1 differentiation, the role of the activation-induced cytosine deaminase gene in B-cell development, the characterization of CD4(+)CD25(+) regulatory T cells, and the use of dynamic imaging to study MHC class II transport and T-cell and dendritic cell membrane interactions. Articles related to clinical immunology that were selected for review include the description of immunodeficiency caused by caspase 8 deficiency; a case series report on X-linked agammaglobulinemia; the mechanism of action, efficacy, and complications of intravenous immunoglobulin; mechanisms of autoimmunity diseases; and advances in HIV pathogenesis and vaccine development. We also reviewed two articles that explore the possible alterations of the immune system caused by spaceflights, a new field with increasing importance as human space expeditions become a reality in the 21st century.

Promoter Methylation Analysis of IDH Genes in Human Gliomas

International Nuclear Information System (INIS)

Flanagan, Simon; Lee, Maggie; Li, Cheryl C. Y.; Suter, Catherine M.; Buckland, Michael E.

2012-01-01

Mutations in isocitrate dehydrogenase (IDH)-1 or -2 are found in the majority of WHO grade II and III astrocytomas and oligodendrogliomas, and secondary glioblastomas. Almost all described mutations are heterozygous missense mutations affecting a conserved arginine residue in the substrate binding site of IDH1 (R132) or IDH2 (R172). But the exact mechanism of IDH mutations in neoplasia is not understood. It has been proposed that IDH mutations impart a “toxic gain-of-function” to the mutant protein, however a dominant-negative effect of mutant IDH has also been described, implying that IDH may function as a tumor suppressor gene. As most, if not all, tumor suppressor genes are inactivated by epigenetic silencing, in a wide variety of tumors, we asked if IDH1 or IDH2 carry the epigenetic signature of a tumor suppressor by assessing cytosine methylation at their promoters. Methylation was quantified in 68 human brain tumors, including both IDH-mutant and IDH wildtype, by bisulfite pyrosequencing. In all tumors examined, CpG methylation levels were less than 8%. Our data demonstrate that inactivation of IDH function through promoter hypermethylation is not common in human gliomas and other brain tumors. These findings do not support a tumor suppressor role for IDH genes in human gliomas.

A novel AVPR2 gene mutation of X-linked congenital nephrogenic diabetes insipidus in an Asian pedigree.

Science.gov (United States)

Guo, Wei-Hong; Li, Qiang; Wei, Hong-Yan; Lu, Hong-Yan; Qu, Hui-Qi; Zhu, Mei

2016-10-01

Polyuria and polydipsia are the characteristics of congenital nephrogenic diabetes insipidus (CNDI). Approximately 90% of all patients with CNDI have X-linked hereditary disease, which is due to a mutation of the arginine vasopressin receptor 2 ( AVPR2) gene. This case report describes a 54-year-old male with polyuria and polydipsia and several male members of his pedigree who had the same symptoms. The proband was diagnosed with diabetes insipidus using a water-deprivation and arginine vasopressin stimulation test. Genomic DNA from the patient and his family members was extracted and the AVPR2 gene was sequenced. A novel missense mutation of a cytosine to guanine transition at position 972 (c.972C > G) was found, which resulted in the substitution of isoleucine for methionine at amino acid position 324 (p.I324M) in the seventh transmembrane domain of the protein. The proband's mother and daughter were heterozygous for this mutation. The novel mutation of the AVPR2 gene further broadens the phenotypic spectrum of the AVPR2 gene.

Are genes destiny? Have adenine, cytosine, guanine and thymine replaced Lachesis, Clotho and Atropos as the weavers of our fate?

Science.gov (United States)

Eisenberg, Leon

2005-02-01

It is as futile to ask how much of the phenotype of an organism is due to nature and how much to its nurture as it is to determine how much of the area of a rectangle is due to its length and how much to its height. Phenotype and area are joint products. The spectacular success of genomics, unfortunately, threatens to re-awaken belief in genes as the principal determinants of human behavior. This paper develops the thesis that gene expression is modified by environmental inputs and that the impact of the environment on a given organism is modified by its genome. Genes set the boundaries of the possible; environments parse out the actual.

Diagnostic value of sputum adenosine deaminase (ADA) level in pulmonary tuberculosis.

Science.gov (United States)

Binesh, Fariba; Jalali, Hadi; Zare, Mohammad Reza; Behravan, Farhad; Tafti, Arefeh Dehghani; Behnaz, Fatemah; Tabatabaee, Mohammad; Shahcheraghi, Seyed Hossein

2016-06-01

Tuberculosis is still a considerable health problem in many countries. Rapid diagnosis of this disease is important, and adenosine deaminase (ADA) has been used as a diagnostic test. The aim of this study was to assess the diagnostic value of ADA in the sputum of patients with pulmonary tuberculosis. The current study included 40 patients with pulmonary tuberculosis (culture positive, smear ±) and 42 patients with non tuberculosis pulmonary diseases (culture negative). ADA was measured on all of the samples. The median value of ADA in non-tuberculosis patients was 2.94 (4.2) U/L and 4.01 (6.54) U/L in tuberculosis patients, but this difference was not statistically significant (p=0.100). The cut-off point of 3.1 U/L had a sensitivity of 61% and a specificity of 53%, the cut-off point of 2.81 U/L had a sensitivity of 64% and a specificity of 50% and the cut-off point of 2.78 U/L had a sensitivity of 65% and a specificity of 48%. The positive predictive values for cut-off points of 3.1, 2.81 and 2.78 U/L were 55.7%, 57.44% and 69.23%, respectively. The negative predictive values for the abovementioned cut-off points were 56.75%, 57.14% and 55.88%, respectively. Our results showed that sputum ADA test is neither specific nor sensitive. Because of its low sensitivity and specificity, determination of sputum ADA for the diagnosis of pulmonary tuberculosis is not recommended.

Circulating type 1 vaccine-derived poliovirus may evolve under the pressure of adenosine deaminases acting on RNA.

Science.gov (United States)

Liu, Yanhan; Ma, Tengfei; Liu, Jianzhu; Zhao, Xiaona; Cheng, Ziqiang; Guo, Huijun; Xu, Ruixue; Wang, Shujing

2015-01-01

Poliovirus, the causative agent of poliomyelitis, is a human enterovirus and member of the Picornaviridae family. An effective live-attenuated poliovirus vaccine strain (Sabin 1) has been developed and has protected humans from polio. However, a few cases of vaccine virulence reversion have been documented in several countries. For instance, circulating type 1 vaccine-derived poliovirus is a highly pathogenic poliovirus that evolved from an avirulent strain, but the mechanism by which vaccine strains undergo reversion remains unclear. In this study, vaccine strains exhibited A to G/U to C and G to A/C to U hypermutations in the reversed evolution of Sabin 1. Furthermore, the mutation ratios of U to C and C to U were higher than those of other mutation types. Dinucleotide editing context was then analyzed. Results showed that A to G and U to C mutations exhibited preferences similar to adenosine deaminases acting on RNA (ADAR). Hence, ADARs may participate in poliovirus vaccine evolution.

DNA cytosine methylation in the bovine leukemia virus promoter is associated with latency in a lymphoma-derived B-cell line: potential involvement of direct inhibition of cAMP-responsive element (CRE)-binding protein/CRE modulator/activation transcription factor binding.

Science.gov (United States)

Pierard, Valérie; Guiguen, Allan; Colin, Laurence; Wijmeersch, Gaëlle; Vanhulle, Caroline; Van Driessche, Benoît; Dekoninck, Ann; Blazkova, Jana; Cardona, Christelle; Merimi, Makram; Vierendeel, Valérie; Calomme, Claire; Nguyên, Thi Liên-Anh; Nuttinck, Michèle; Twizere, Jean-Claude; Kettmann, Richard; Portetelle, Daniel; Burny, Arsène; Hirsch, Ivan; Rohr, Olivier; Van Lint, Carine

2010-06-18

Bovine leukemia virus (BLV) proviral latency represents a viral strategy to escape the host immune system and allow tumor development. Besides the previously demonstrated role of histone deacetylation in the epigenetic repression of BLV expression, we showed here that BLV promoter activity was induced by several DNA methylation inhibitors (such as 5-aza-2'-deoxycytidine) and that overexpressed DNMT1 and DNMT3A, but not DNMT3B, down-regulated BLV promoter activity. Importantly, cytosine hypermethylation in the 5'-long terminal repeat (LTR) U3 and R regions was associated with true latency in the lymphoma-derived B-cell line L267 but not with defective latency in YR2 cells. Moreover, the virus-encoded transactivator Tax(BLV) decreased DNA methyltransferase expression levels, which could explain the lower level of cytosine methylation observed in the L267(LTaxSN) 5'-LTR compared with the L267 5'-LTR. Interestingly, DNA methylation inhibitors and Tax(BLV) synergistically activated BLV promoter transcriptional activity in a cAMP-responsive element (CRE)-dependent manner. Mechanistically, methylation at the -154 or -129 CpG position (relative to the transcription start site) impaired in vitro binding of CRE-binding protein (CREB) transcription factors to their respective CRE sites. Methylation at -129 CpG alone was sufficient to decrease BLV promoter-driven reporter gene expression by 2-fold. We demonstrated in vivo the recruitment of CREB/CRE modulator (CREM) and to a lesser extent activating transcription factor-1 (ATF-1) to the hypomethylated CRE region of the YR2 5'-LTR, whereas we detected no CREB/CREM/ATF recruitment to the hypermethylated corresponding region in the L267 cells. Altogether, these findings suggest that site-specific DNA methylation of the BLV promoter represses viral transcription by directly inhibiting transcription factor binding, thereby contributing to true proviral latency.

Carrier frequency of a nonsense mutation in the adenosine deaminase (ADA) gene implies a high incidence of ADA-deficient severe combined immunodeficiency (SCID) in Somalia and a single, common haplotype indicates common ancestry

DEFF Research Database (Denmark)

Sanchez Sanchez, Juan Jose; Monaghan, Gemma; Børsting, Claus

2007-01-01

Inherited adenosine deaminase (ADA) deficiency is a rare metabolic disorder that causes immunodeficiency, varying from severe combined immunodeficiency (SCID) in the majority of cases to a less severe form in a small minority of patients. Five patients of Somali origin from four unrelated families......, with severe ADA-SCID, were registered in the Greater London area. Patients and their parents were investigated for the nonsense mutation Q3X (ADA c7C>T), two missense mutations K80R (ADA c239A>G) and R142Q (ADA c425G>A), and a TAAA repeat located at the 3' end of an Alu element (AluVpA) positioned 1.1 kb...... upstream of the ADA transcription start site. All patients were homozygous for the haplotype ADA-7T/ADA-239G/ADA-425G/AluVpA7. Among 207 Somali immigrants to Denmark, the frequency of ADA c7C>T and the maximum likelihood estimate of the frequency of the haplotype ADA-7T/ADA-239G/ADA-425G/AluVpA7 were both...

Effect of heavy metals on acdS gene expression in Herbaspirillium sp. GW103 isolated from rhizosphere soil.

Science.gov (United States)

Loganathan, Praburaman; Myung, Hyun; Muthusamy, Govarthanan; Lee, Kui-Jae; Seralathan, Kamala-Kannan; Oh, Byung-Taek

2015-10-01

This study aimed to understand the influence of heavy metals on 1-aminocyclopropane-1-carboxylate deaminase activity (ACCD) and acdS gene expression in Herbaspirillium sp. GW103. The GW103 strain ACCD activity decreased in cells grown in a medium supplemented with Pb and As, whereas cells grown in medium supplemented with Cu showed increase in enzyme activity. The GW103 strain produced 262.2 ± 6.17 μmol of α-ketobutyrate per milligram of protein per hour during ACC deamination at 25 °C after 24 h incubation. Using a PCR approach, an acdS coding-gene of 1.06 kbp was amplified in isolate GW103, showing 92% identity with Herbaspirillum seropedicae SmR1 acdS gene. Real time quantitative polymerase chain reaction results indicate that the acdS expression rate was increased (7.1-fold) in the presence of Cu, whereas it decreased (0.2- and 0.1-fold) in the presence of As and Pb. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adenosine Deaminase Inhibitor EHNA Exhibits a Potent Anticancer Effect Against Malignant Pleural Mesothelioma

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Yasuhiro Nakajima

2015-01-01

Full Text Available Background/Aims: Malignant pleural mesothelioma (MPM is an aggressive malignant tumor and an effective therapy has been little provided as yet. The present study investigated the possibility for the adenosine deaminase (ADA inhibitor EHNA as a target of MPM treatment. Methods: MTT assay, TUNEL staining, monitoring of intracellular adenosine concentrations, and Western blotting were carried out in cultured human MPM cell lines without and with knocking-down ADA. The in vivo effect of EHNA was assessed in mice inoculated with NCI-H2052 MPM cells. Results: EHNA induced apoptosis of human MPM cell lines in a concentration (0.01-1 mM- and treatment time (24-48 h-dependent manner, but such effect was not obtained with another ADA inhibitor pentostatin. EHNA increased intracellular adenosine concentrations in a treatment time (3-9 h-dependent manner. EHNA-induced apoptosis of MPM cells was mimicked by knocking-down ADA, and the effect was neutralized by the adenosine kinase inhibitor ABT-702. EHNA clearly suppressed tumor growth in mice inoculated with NCI-H2052 MPM cells. Conclusion: The results of the present study show that EHNA induces apoptosis of MPM cells by increasing intracellular adenosine concentrations, to convert to AMP, and effectively prevents MPM cell proliferation. This suggests that EHNA may be useful for treatment of the tragic neoplasm MPM.

Variation of DNA methylation patterns associated with gene expression in rice (Oryza sativa) exposed to cadmium.

Science.gov (United States)

Feng, Sheng Jun; Liu, Xue Song; Tao, Hua; Tan, Shang Kun; Chu, Shan Shan; Oono, Youko; Zhang, Xian Duo; Chen, Jian; Yang, Zhi Min

2016-12-01

We report genome-wide single-base resolution maps of methylated cytosines and transcriptome change in Cd-exposed rice. Widespread differences were identified in CG and non-CG methylation marks between Cd-exposed and Cd-free rice genomes. There are 2320 non-redundant differentially methylated regions detected in the genome. RNA sequencing revealed 2092 DNA methylation-modified genes differentially expressed under Cd exposure. More genes were found hypermethylated than those hypomethylated in CG, CHH and CHG (where H is A, C or T) contexts in upstream, gene body and downstream regions. Many of the genes were involved in stress response, metal transport and transcription factors. Most of the DNA methylation-modified genes were transcriptionally altered under Cd stress. A subset of loss of function mutants defective in DNA methylation and histone modification activities was used to identify transcript abundance of selected genes. Compared with wide type, mutation of MET1 and DRM2 resulted in general lower transcript levels of the genes under Cd stress. Transcripts of OsIRO2, OsPR1b and Os09g02214 in drm2 were significantly reduced. A commonly used DNA methylation inhibitor 5-azacytidine was employed to investigate whether DNA demethylation affected physiological consequences. 5-azacytidine provision decreased general DNA methylation levels of selected genes, but promoted growth of rice seedlings and Cd accumulation in rice plant. © 2016 John Wiley & Sons Ltd.

SU-C-303-01: Activation-Induced Cytidine Deaminase Confers Cancer Resistance to Radiation Therapy

International Nuclear Information System (INIS)

Yi, S; La Count, S; Liu, J; Bai, X; Lu, L

2015-01-01

Purpose: To study the role of activation-induced cytidine deaminase (AID) in malignant cell resistance to radiation therapy. Methods: We first developed several small devices that could be used to adopt radiation beams from clinical high dose rate brachy therapy (HDR) or linac-based megavoltage machines to perform pre-clinical cell and mouse experiments. Then we used these devices to deliver radiation to AID-positive and AID-silenced cancer cells or tumors formed by these cells in mice. Cells and mice bearing tumors received the same dose under the same experimental conditions. For cells, we observed the apoptosis and the cell survival rate over time. For mice bearing tumors, we measured and recorded the tumor sizes every other day for 4 weeks. Results: For cell experiments, we found that the AID-positive cells underwent much less apoptosis compared with AID-silenced cells upon radiation. And for mouse experiments, we found that AID-positive tumors grew significantly faster than the AID-silenced tumors despite of receiving the same doses of radiation. Conclusion: Our study suggests that AID may confer cancer resistance to radiation therapy, and AID may be a significant biomarker predicting cancer resistance to radiation therapy for certain cancer types

Mechanism of interaction of the antileukemic drug cytosine arabinoside with aromatic peptides: role of sugar conformation and peptide backbone.

Science.gov (United States)

Datta, G; Hosur, R V; Verma, N C; Khetrapal, C L; Gurnani, S

1989-01-01

Interaction of the antileukemic drugs, cytosine-arabinoside (Ara-C) and adenosine-arabinoside (Ara-A) and a structural analogue, cytidine, with aromatic dipeptides has been studied by fluorescence and NMR spectroscopy. Ara-C and cytidine bind tryptophanyl and histidyl dipeptides but not tyrosyl dipeptides, while Ara-A does not bind to any of them. Both studies indicate association involving stacking of aromatic moieties. NMR spectra also indicate a protonation of the histidine moiety by Ara-C. In case of cytidine, the chemical shifts observed on binding to His-Phe imply that the backbone protons of the dipeptide participate in the binding. The conformation of the sugar and the base seem to play a very important role in the binding phenomenon as three similar molecules, Ara-C, Ara-A and cytidine bind in totally different ways.

Suppression of prolactin gene expression in GH cells correlates with site-specific DNA methylation.

Science.gov (United States)

Zhang, Z X; Kumar, V; Rivera, R T; Pasion, S G; Chisholm, J; Biswas, D K

1989-10-01

Prolactin- (PRL) producing and nonproducing subclones of the GH line of (rat) pituitary tumor cells have been compared to elucidate the regulatory mechanisms of PRL gene expression. Particular emphasis was placed on delineating the molecular basis of the suppressed state of the PRL gene in the prolactin-nonproducing (PRL-) GH subclone (GH(1)2C1). We examined six methylatable cytosine residues (5, -CCGG- and 1, -GCGC-) within the 30-kb region of the PRL gene in these subclones. This analysis revealed that -CCGG-sequences of the transcribed region, and specifically, one in the fourth exon of the PRL gene, were heavily methylated in the PRL-, GH(1)2C1 cells. Furthermore, the inhibition of PRL gene expression in GH(1)2C1 was reversed by short-term treatment of the cells with a sublethal concentration of azacytidine (AzaC), an inhibitor of DNA methylation. The reversion of PRL gene expression by AzaC was correlated with the concurrent demethylation of the same -CCGG- sequences in the transcribed region of PRL gene. An inverse correlation between PRL gene expression and the level of methylation of the internal -C- residues in the specific -CCGG-sequence of the transcribed region of the PRL gene was demonstrated. The DNase I sensitivity of these regions of the PRL gene in PRL+, PRL-, and AzaC-treated cells was also consistent with an inverse relationship between methylation state, a higher order of structural modification, and gene expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Pyrimidine Pool Disequilibrium Induced by a Cytidine Deaminase Deficiency Inhibits PARP-1 Activity, Leading to the Under Replication of DNA.

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Simon Gemble

2015-07-01

Full Text Available Genome stability is jeopardized by imbalances of the dNTP pool; such imbalances affect the rate of fork progression. For example, cytidine deaminase (CDA deficiency leads to an excess of dCTP, slowing the replication fork. We describe here a novel mechanism by which pyrimidine pool disequilibrium compromises the completion of replication and chromosome segregation: the intracellular accumulation of dCTP inhibits PARP-1 activity. CDA deficiency results in incomplete DNA replication when cells enter mitosis, leading to the formation of ultrafine anaphase bridges between sister-chromatids at "difficult-to-replicate" sites such as centromeres and fragile sites. Using molecular combing, electron microscopy and a sensitive assay involving cell imaging to quantify steady-state PAR levels, we found that DNA replication was unsuccessful due to the partial inhibition of basal PARP-1 activity, rather than slower fork speed. The stimulation of PARP-1 activity in CDA-deficient cells restores replication and, thus, chromosome segregation. Moreover, increasing intracellular dCTP levels generates under-replication-induced sister-chromatid bridges as efficiently as PARP-1 knockdown. These results have direct implications for Bloom syndrome (BS, a rare genetic disease combining susceptibility to cancer and genomic instability. BS results from mutation of the BLM gene, encoding BLM, a RecQ 3'-5' DNA helicase, a deficiency of which leads to CDA downregulation. BS cells thus have a CDA defect, resulting in a high frequency of ultrafine anaphase bridges due entirely to dCTP-dependent PARP-1 inhibition and independent of BLM status. Our study describes previously unknown pathological consequences of the distortion of dNTP pools and reveals an unexpected role for PARP-1 in preventing DNA under-replication and chromosome segregation defects.

Diagnostic significance of pleural fluid adenosine deaminase activity in tuberculous pleurisy

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Sharmeen Ahmed

2011-01-01

Full Text Available Diagnosis of tuberculous pleural effusion (TPE is difficult because of its non-specific clinical presentation and insufficient efficiency of conventional diagnostic methods. The study was carried out to evaluate the utility of adenosine deaminase (ADA activity in pleural fluid for the diagnosis of TPE. ADA activity was measured in pleural fluid of 103 pleural effusion patients by colorimetric method using a commercial ADA assay kit. The diagnosis of TPE was made from pleural fluid examinations (including cytology, biochemistry, and bacteriology and pleural biopsy. Patient with negative result of this methods were diagnosed by response of empirical treatment. Out of 130 cases, 62 (61.1% had TPE and the remaining 41 (39.8% had pleural effusion due to non tuberculous diseases. There was statistically significant difference (p < 0.001 between the mean of pleural fluid ADA levels (70.82±22.54 U/L in TPE group and (30.07±22.93 U/L in non-TPE group. Of 62 TPE cases, microscopy for AFB and culture for M.tuberculosis in pleural fluid revealed positivity in 9.6% and 22.5% cases respectively, and biopsy of pleura showed typical epithelioid granuloma in only 43.5% cases. The cut-off value of ADA for diagnosing TPE was 40 U/L using a ROC curve, with a sensitivity of 94% and specificity of 88%. Positive and negative predictive value of ADA assay were 92% and 90% respectively. The overall test accuracy was 90%. Pleural fluid ADA assay is therefore a simple, rapid, highly sensitive and specific adjunct test for diagnosis of TPE. Ibrahim Med. Coll. J. 2011; 5(1: 1-5

A mutation in the LAMC2 gene causes the Herlitz junctional epidermolysis bullosa (H-JEB in two French draft horse breeds

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Guérin Gérard

2003-03-01

Full Text Available Abstract Epidermolysis bullosa (EB is a heterogeneous group of inherited diseases characterised by skin blistering and fragility. In humans, one of the most severe forms of EB known as Herlitz-junctional EB (H-JEB, is caused by mutations in the laminin 5 genes. EB has been described in several species, like cattle, sheep, dogs, cats and horses where the mutation, a cytosine insertion in exon 10 of the LAMC2 gene, was very recently identified in Belgian horses as the mutation responsible for JEB. In this study, the same mutation was found to be totally associated with the JEB phenotype in two French draft horse breeds, Trait Breton and Trait Comtois. This result provides breeders a molecular test to better manage their breeding strategies by genetic counselling.

Ultrasensitive Direct Quantification of Nucleobase Modifications in DNA by Surface-Enhanced Raman Scattering: The Case of Cytosine.

Science.gov (United States)

Morla-Folch, Judit; Xie, Hai-nan; Gisbert-Quilis, Patricia; Gómez-de Pedro, Sara; Pazos-Perez, Nicolas; Alvarez-Puebla, Ramon A; Guerrini, Luca

2015-11-09

Recognition of chemical modifications in canonical nucleobases of nucleic acids is of key importance since such modified variants act as different genetic encoders, introducing variability in the biological information contained in DNA. Herein, we demonstrate the feasibility of direct SERS in combination with chemometrics and microfluidics for the identification and relative quantification of 4 different cytosine modifications in both single- and double-stranded DNA. The minute amount of DNA required per measurement, in the sub-nanogram regime, removes the necessity of pre-amplification or enrichment steps (which are also potential sources of artificial DNA damages). These findings show great potentials for the development of fast, low-cost and high-throughput screening analytical devices capable of detecting known and unknown modifications in nucleic acids (DNA and RNA) opening new windows of activity in several fields such as biology, medicine and forensic sciences. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pleiotropic phenotypes of the salt-tolerant and cytosine ...

Indian Academy of Sciences (India)

of Catharanthus roseus possessing Mendelian inheritance. Renu Kumari, Vishakha ...... Bowman J. L. 2004 Class III HD-Zip gene regulation, the golden fleece of .... Arabidopsis has multiple effects on plant development, includ- ing early flowering and .... germination is revealed by the misexpression of a homologous gene ...

Recombination and horizontal transfer of nodulation and ACC deaminase (acdS) genes within Alpha- and Betaproteobacteria nodulating legumes of the Cape Fynbos biome.

Science.gov (United States)

Lemaire, Benny; Van Cauwenberghe, Jannick; Chimphango, Samson; Stirton, Charles; Honnay, Olivier; Smets, Erik; Muasya, A Muthama

2015-11-01

The goal of this work is to study the evolution and the degree of horizontal gene transfer (HGT) within rhizobial genera of both Alphaproteobacteria (Mesorhizobium, Rhizobium) and Betaproteobacteria (Burkholderia), originating from South African Fynbos legumes. By using a phylogenetic approach and comparing multiple chromosomal and symbiosis genes, we revealed conclusive evidence of high degrees of horizontal transfer of nodulation genes among closely related species of both groups of rhizobia, but also among species with distant genetic backgrounds (Rhizobium and Mesorhizobium), underscoring the importance of lateral transfer of symbiosis traits as an important evolutionary force among rhizobia of the Cape Fynbos biome. The extensive exchange of symbiosis genes in the Fynbos is in contrast with a lack of significant events of HGT among Burkholderia symbionts from the South American Cerrado and Caatinga biome. Furthermore, homologous recombination among selected housekeeping genes had a substantial impact on sequence evolution within Burkholderia and Mesorhizobium. Finally, phylogenetic analyses of the non-symbiosis acdS gene in Mesorhizobium, a gene often located on symbiosis islands, revealed distinct relationships compared to the chromosomal and symbiosis genes, suggesting a different evolutionary history and independent events of gene transfer. The observed events of HGT and incongruence between different genes necessitate caution in interpreting topologies from individual data types. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Origin and Evolution of Nitrogen Fixation Genes on Symbiosis Islands and Plasmid in Bradyrhizobium

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Okubo, Takashi; Piromyou, Pongdet; Tittabutr, Panlada; Teaumroong, Neung; Minamisawa, Kiwamu

2016-01-01

The nitrogen fixation (nif) genes of nodule-forming Bradyrhizobium strains are generally located on symbiosis islands or symbiosis plasmids, suggesting that these genes have been transferred laterally. The nif genes of rhizobial and non-rhizobial Bradyrhizobium strains were compared in order to infer the evolutionary histories of nif genes. Based on all codon positions, the phylogenetic tree of concatenated nifD and nifK sequences showed that nifDK on symbiosis islands formed a different clade from nifDK on non-symbiotic loci (located outside of symbiosis islands and plasmids) with elongated branches; however, these genes were located in close proximity, when only the 1st and 2nd codon positions were analyzed. The guanine (G) and cytosine (C) content of the 3rd codon position of nifDK on symbiosis islands was lower than that on non-symbiotic loci. These results suggest that nif genes on symbiosis islands were derived from the non-symbiotic loci of Bradyrhizobium or closely related strains and have evolved toward a lower GC content with a higher substitution rate than the ancestral state. Meanwhile, nifDK on symbiosis plasmids clustered with nifDK on non-symbiotic loci in the tree representing all codon positions, and the GC content of symbiotic and non-symbiotic loci were similar. These results suggest that nif genes on symbiosis plasmids were derived from the non-symbiotic loci of Bradyrhizobium and have evolved with a similar evolutionary pattern and rate as the ancestral state. PMID:27431195

Pathophysiology of B-cell intrinsic immunoglobulin class switch recombination deficiencies.

Science.gov (United States)

Durandy, Anne; Taubenheim, Nadine; Peron, Sophie; Fischer, Alain

2007-01-01

B-cell intrinsic immunoglobulin class switch recombination (Ig-CSR) deficiencies, previously termed hyper-IgM syndromes, are genetically determined conditions characterized by normal or elevated serum IgM levels and an absence or very low levels of IgG, IgA, and IgE. As a function of the molecular mechanism, the defective CSR is variably associated to a defect in the generation of somatic hypermutations (SHMs) in the Ig variable region. The study of Ig-CSR deficiencies contributed to a better delineation of the mechanisms underlying CSR and SHM, the major events of antigen-triggered antibody maturation. Four Ig-CSR deficiency phenotypes have been so far reported: the description of the activation-induced cytidine deaminase (AID) deficiency (Ig-CSR deficiency 1), caused by recessive mutations of AICDA gene, characterized by a defect in CSR and SHM, clearly established the role of AID in the induction of the Ig gene rearrangements underlying CSR and SHM. A CSR-specific function of AID has, however, been detected by the observation of a selective CSR defect caused by mutations affecting the C-terminus of AID. Ig-CSR deficiency 2 is the consequence of uracil-N-glycosylase (UNG) deficiency. Because UNG, a molecule of the base excision repair machinery, removes uracils from DNA and AID deaminates cytosines into uracils, that observation indicates that the AID-UNG pathway directly targets DNA of switch regions from the Ig heavy-chain locus to induce the CSR process. Ig-CSR deficiencies 3 and 4 are characterized by a selective CSR defect resulting from blocks at distinct steps of CSR. A further understanding of the CSR machinery is expected from their molecular definition.

Human tumour xenografts established and serially transplanted in mice immunologically deprived by thymectomy, cytosine arabinoside and whole-body irradiation

International Nuclear Information System (INIS)

Selby, P.J.; Thomas, J.M.; Peckham, M.J.

1980-01-01

Mice immunologically deprived by thymectomy, cytosine arabinoside treatment and whole-body irradiation were used to study the growth of human tumours as xenografts. 10/16 melanoma biopsies, 4/13 ovarian carcinoma biopsies and 3/6 uterine cancer biopsies grew as serially transplantable xenograft lines. The tumour lines were studied through serial passages by histology, histo-chemistry, electron microscopy, chromosome analysis, immune fluorescence, growth rate measurement and mitotic counts. They retained the characteristics of the tumours of origin, with the exception of loss of pigmentation in two melanomas, histological dedifferentiation in the uterine carcinomas, and increased mitotic frequency and growth rate in some melanomas. It was concluded that this type of animal preparation is as useful as alternative methods of immunological deprivation, or as athymic nude mice, for the growth of human tumour xenografts, at least for some experimental purposes. (author)

DNA (cytosine-5-methyltransferase 3B (DNMT 3B polymorphism and risk of Down syndrome offspring

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Cláudia Melo de Moura

2018-01-01

Full Text Available Down syndrome (DS is the most common form of human genetic mental retardation. Several polymorphisms in genes coding folic acid cycle enzymes have been associated to the risk of bearing a DS child; however, the results are controversial. S-adenosyl-l-methionine (SAM is an important intermediate of folic acid pathway and acts as methyl donor and substrate for DNA (cytosine-5-methyltransferase 3B (DNMT3B – EC 2.1.1.37 de novo methylation processes during embryogenesis. Recent studies suggest that a functional polymorphism of DNMT 3B in maternal genotype may be associated with a decreased risk of having a DS child. We herein investigate the association of this polymorphism with the occurrence of DS in a Brazilian population. We have genotyped 111 mothers of DS infants (MDS and 212 control mothers (CM through PCR-RFLP. The observed genotypic frequencies were CC = 0.22; CT = 0.49 and TT = 0.29 in CM, and CC = 0.30; CT = 0.52 and TT = 0.18 in MDS. Allelic frequencies were C = 0.47 and T = 0.53 in CM and C = 0.56 and T = 0.44 in MDS. No deviation of HWE was observed, and both DNMT 3B rs2424913 genotype (χ2 = 4.53; DF = 1; P = 0.03 and allelic (χ2 = 4.90; DF = 1; P = 0.03 frequencies show significant differences between MDS and CM. The presence of the mutant DNMT 3B T allele decreases 30% the risk of bearing a DS child (OR = 0.69; 95% CI: 0.50–0.96; P = 0.03, and the risk is diminished up to 45% in association with the homozygous genotype (OR = 0.54; 95% CI: 0.31–0.96; P = 0.04. Our results suggest that women harboring the single nucleotide polymorphism DNMT 3B rs2424913 have a decreased risk of a DS pregnancy, and further studies are necessary to confirm this protective effect.

Significance of determination of serum cytidine deaminase (CD) levels for diagnosis of active rheumatoid arthritis (RA)

International Nuclear Information System (INIS)

Xiao Chuangqing; Jang Xiaogong; He Yunnan

2005-01-01

Objective: To determine the clinical value of measurement of serum cytidine deaminase (CD) levels in patients with active rheumatoid arthritis (RA). Methods: Serum levels of CD were detected with spectrophotometry, in 33 patients with active RA and 60 controls. The erythrocyte sedimentation rate (ESR) and CRP content were also determined in both groups. Results: The ser- um CD contents in patients with active RA(14.80 ± 2.11U/ml) were significantly higher than those in controls(4.86±1.86 U/ml,P<0.01). The CRP contents (51.46 ± 20.43mg/L) and ESR readings(85.03 ± 27.6mm/h) in the patients were also significantly higher than those in the controls(3.40 ± 2.21mg/L and 13.04 ± 4.89mm/h respectively, all P<0.01). In the patients, the serum CD contents were linearly positively correlated with the ESR contents and CRP readings (r=0.6324 and 0.8013 respectively, P <0.01). Conclusion: Serum CD is an early biochemical marker for diagnosis of active rheumatoid arthritis and is also of prognostic value. (authors)

Host range, symbiotic effectiveness and nodulation competitiveness ...

African Journals Online (AJOL)

SERVER

2008-04-17

Apr 17, 2008 ... ERIC-PCR DNA fingerprinting patterns were used to identify the ... Apart from cowpea where all the isolates were effective, there were significant ..... aminocyclopropane-1-carboxylate deaminase gene in Sinorhizobium.

A Phenotypic Screen for Functional Mutants of Human Adenosine Deaminase Acting on RNA 1.

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Wang, Yuru; Havel, Jocelyn; Beal, Peter A

2015-11-20

Adenosine deaminases acting on RNA (ADARs) are RNA-editing enzymes responsible for the conversion of adenosine to inosine at specific locations in cellular RNAs. ADAR1 and ADAR2 are two members of the family that have been shown to be catalytically active. Earlier, we reported a phenotypic screen for the study of human ADAR2 using budding yeast S. cerevisiae as the host system. While this screen has been successfully applied to the study of ADAR2, it failed with ADAR1. Here, we report a new reporter that uses a novel editing substrate and is suitable for the study of ADAR1. We screened plasmid libraries with randomized codons for two important residues in human ADAR1 (G1007 and E1008). The screening results combined with in vitro deamination assays led to the identification of mutants that are more active than the wild type protein. Furthermore, a screen of the ADAR1 E1008X library with a reporter construct bearing an A•G mismatch at the editing site suggests one role for the residue at position 1008 is to sense the identity of the base pairing partner for the editing site adenosine. This work has provided a starting point for future in vitro evolution studies of ADAR1 and led to new insight into ADAR's editing site selectivity.

Concerted bis-alkylating reactivity of clerocidin towards unpaired cytosine residues in DNA

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Richter, Sara N.; Menegazzo, Ileana; Fabris, Daniele; Palumbo, Manlio

2004-01-01

Clerocidin (CL) is a topoisomerase II poison, which cleaves DNA irreversibly at guanines (G) and reversibly at cytosines (C). Furthermore, the drug can induce enzyme-independent strand breaks at the G and C level. It has been previously shown that G-damage is induced by alkylation of the guanine N7, followed by spontaneous depurination and nucleic acid cleavage, whereas scission at C is obtained only after treatment with hot alkali, and no information is available to explain the nature of this damage. We present here a systematic study on the reactivity of CL towards C both in the DNA environment and in solution. Selected synthetic derivatives were employed to evaluate the role of each chemical group of the drug. The structure of CL–dC adduct was then characterized by tandem mass spectrometry and NMR: the adduct is a stable condensed ring system resulting from a concerted electrophilic attack of the adjacent carbonyl and epoxide groups of CL towards the exposed NH2 and N3, respectively. This reaction mechanism, shown here for the first time, is characterized by faster kinetic rates than alkylation at G, due to the fact that the rate-determining step, alkylation at the epoxide, is an intramolecular process, provided a Schiff base linking CL and C can rapidly form, whereas the corresponding reaction of G N7 is intermolecular. These results provide helpful hints to explain the reversible/irreversible nature of topoisomerase II mediated DNA damage produced by CL at C/G steps. PMID:15494453

Hydroxymethylation at Gene Regulatory Regions Directs Stem/Early Progenitor Cell Commitment during Erythropoiesis

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Jozef Madzo

2014-01-01

Full Text Available Hematopoietic stem cell differentiation involves the silencing of self-renewal genes and induction of a specific transcriptional program. Identification of multiple covalent cytosine modifications raises the question of how these derivatized bases influence stem cell commitment. Using a replicative primary human hematopoietic stem/progenitor cell differentiation system, we demonstrate dynamic changes of 5-hydroxymethylcytosine (5-hmC during stem cell commitment and differentiation to the erythroid lineage. Genomic loci that maintain or gain 5-hmC density throughout erythroid differentiation contain binding sites for erythroid transcription factors and several factors not previously recognized as erythroid-specific factors. The functional importance of 5-hmC was demonstrated by impaired erythroid differentiation, with augmentation of myeloid potential, and disrupted 5-hmC patterning in leukemia patient-derived CD34+ stem/early progenitor cells with TET methylcytosine dioxygenase 2 (TET2 mutations. Thus, chemical conjugation and affinity purification of 5-hmC-enriched sequences followed by sequencing serve as resources for deciphering functional implications for gene expression during stem cell commitment and differentiation along a particular lineage.

Role of methionine on epigenetic modification of DNA methylation and gene expression in animals

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Naifeng Zhang

2018-03-01

Full Text Available DNA methylation is one of the main epigenetic phenomena affecting gene expression. It is an important mechanism for the development of embryo, growth and health of animals. As a key nutritional factor limiting the synthesis of protein, methionine serves as the precursor of S-adenosylmethionine (SAM in the hepatic one-carbon metabolism. The dietary fluctuation of methionine content can alter the levels of metabolic substrates in one-carbon metabolism, e.g., the SAM, S-adenosylhomocysteine (SAH, and change the expression of genes related to the growth and health of animals by DNA methylation reactions. The ratio of SAM to SAH is called ‘methylation index’ but it should be carefully explained because the complexity of methylation reaction. Alterations of methylation in a specific cytosine-guanine (CpG site, rather than the whole promoter region, might be enough to change gene expression. Aberrant methionine cycle may provoke molecular changes of one-carbon metabolism that results in deregulation of cellular hemostasis and health problems. The importance of DNA methylation has been underscored but the mechanisms of methionine affecting DNA methylation are poorly understood. Nutritional epigenomics provides a promising insight into the targeting epigenetic changes in animals from a nutritional standpoint, which will deepen and expand our understanding of genes, molecules, tissues, and animals in which methionine alteration influences DNA methylation and gene expression. Keywords: Epigenetics, Methionine, DNA methylation, Gene expression, Epigenetic modification

The Binding Interface between Human APOBEC3F and HIV-1 Vif Elucidated by Genetic and Computational Approaches

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Christopher Richards

2015-12-01

Full Text Available APOBEC3 family DNA cytosine deaminases provide overlapping defenses against pathogen infections. However, most viruses have elaborate evasion mechanisms such as the HIV-1 Vif protein, which subverts cellular CBF-β and a polyubiquitin ligase complex to neutralize these enzymes. Despite advances in APOBEC3 and Vif biology, a full understanding of this direct host-pathogen conflict has been elusive. We combine virus adaptation and computational studies to interrogate the APOBEC3F-Vif interface and build a robust structural model. A recurring compensatory amino acid substitution from adaptation experiments provided an initial docking constraint, and microsecond molecular dynamic simulations optimized interface contacts. Virus infectivity experiments validated a long-lasting electrostatic interaction between APOBEC3F E289 and HIV-1 Vif R15. Taken together with mutagenesis results, we propose a wobble model to explain how HIV-1 Vif has evolved to bind different APOBEC3 enzymes and, more generally, how pathogens may evolve to escape innate host defenses.

Assay for mutagenesis in heterozygous diploid human lymphoblasts

Science.gov (United States)

Skopek, Thomas R.; Liber, Howard L.; Penman, Bruce W.; Thilly, William G.; Hoppe, IV, Henry

1981-01-01

An assay is disclosed for determining mutagenic damage caused by the administration of a known or suspected mutagen to diploid human lymphoblastoid cell lines. The gene locus employed for this assay is the gene for thymidine kinase, uridine kinase, or cytidine deaminase. Since human lymphoblastoid cells contain two genes for these enzymes, heterozygotes of human lymphoblastoid cells are used in this assay.

Cloning and analysis of the genes encoding the type IIS restriction-modification system HphI from Haemophilus parahaemolyticus.

Science.gov (United States)

Lubys, A; Lubienè, J; Kulakauskas, S; Stankevicius, K; Timinskas, A; Janulaitis, A

1996-07-15

The genomic region encoding the type IIS restriction-modification (R-M) system HphI (enzymes recognizing the asymmetric sequence 5'-GGTGA-3'/5'-TCACC-3') from Haemophilus parahaemolyticus were cloned into Escherichia coli and sequenced. Sequence analysis of the R-M HphI system revealed three adjacent genes aligned in the same orientation: a cytosine 5 methyltransferase (gene hphIMC), an adenine N6 methyltransferase (hphIMA) and the HphI restriction endonuclease (gene hphIR). Either methyltransferase is capable of protecting plasmid DNA in vivo against the action of the cognate restriction endonuclease. hphIMA methylation renders plasmid DNA resistant to R.Hindill at overlapping sites, suggesting that the adenine methyltransferase modifies the 3'-terminal A residue on the GGTGA strand. Strong homology was found between the N-terminal part of the m6A methyltransferasease and an unidentified reading frame interrupted by an incomplete gaIE gene of Neisseria meningitidis. The HphI R-M genes are flanked by a copy of a 56 bp direct nucleotide repeat on each side. Similar sequences have also been identified in the non-coding regions of H.influenzae Rd DNA. Possible involvement of the repeat sequences in the mobility of the HphI R-M system is discussed.

A highly selective fluorescence sensing platform for nanomolar Hg(II) detection based on cytosine derived quantum dot

Science.gov (United States)

Luo, Liang; Song, Ting; Wang, Haoqiang; Yuan, Qunhui; Zhou, Shenghai

2018-03-01

Inspired by low toxicity and good biocompatibility of biomass derived quantum dot (QD), we herein developed a cytosine derived quantum dot, namely cyt-dot, via a one-step hydrothermal synthesis. The as-prepared cyt-dot emits blue fluorescence (FL) containing abundant oxygen (20.6 at.%) and nitrogen (24.1 at.%) contents. The cyt-dot based sensing platform shows exclusive selectivity for Hg(II) while being insensitive towards Fe(III) and Ag(I), which are important interference that usually cannot be ruled out. The detection limit for Hg(II) is of 11 nM, which is very close to the guideline value of 10 nM allowed by the U.S. Environmental Protection Agency in drinking water. In real water sample analyses, the present sensing platform can fulfil satisfied recoveries ranging from 100% to 108%. Besides, the acidity of solution has almost no effect on the sensing performance of the cyt-dot in a pH range of 5-8, suggesting its potential applications in sensing and bio-imaging.

A novel nonsense mutation in the tyrosinase gene is related to the albinism in a capuchin monkey (Sapajus apella).

Science.gov (United States)

Galante Rocha de Vasconcelos, Felipe Tadeu; Hauzman, Einat; Dutra Henriques, Leonardo; Kilpp Goulart, Paulo Roney; de Faria Galvão, Olavo; Sano, Ronaldo Yuiti; da Silva Souza, Givago; Lynch Alfaro, Jessica; de Lima Silveira, Luis Carlos; Fix Ventura, Dora; Oliveira Bonci, Daniela Maria

2017-05-05

Oculocutaneous Albinism (OCA) is an autosomal recessive inherited condition that affects the pigmentation of eyes, hair and skin. The OCA phenotype may be caused by mutations in the tyrosinase gene (TYR), which expresses the tyrosinase enzyme and has an important role in the synthesis of melanin pigment. The aim of this study was to identify the genetic mutation responsible for the albinism in a captive capuchin monkey, and to describe the TYR gene of normal phenotype individuals. In addition, we identified the subject's species. A homozygous nonsense mutation was identified in exon 1 of the TYR gene, with the substitution of a cytosine for a thymine nucleotide (C64T) at codon 22, leading to a premature stop codon (R22X) in the albino robust capuchin monkey. The albino and five non-albino robust capuchin monkeys were identified as Sapajus apella, based on phylogenetic analyses, pelage pattern and geographic provenance. One individual was identified as S. macrocephalus. We conclude that the point mutation C64T in the TYR gene is responsible for the OCA1 albino phenotype in the capuchin monkey, classified as Sapajus apella.

Molecular analysis of urothelial cancer cell lines for modeling tumor biology and drug response.

Science.gov (United States)

Nickerson, M L; Witte, N; Im, K M; Turan, S; Owens, C; Misner, K; Tsang, S X; Cai, Z; Wu, S; Dean, M; Costello, J C; Theodorescu, D

2017-01-05

The utility of tumor-derived cell lines is dependent on their ability to recapitulate underlying genomic aberrations and primary tumor biology. Here, we sequenced the exomes of 25 bladder cancer (BCa) cell lines and compared mutations, copy number alterations (CNAs), gene expression and drug response to BCa patient profiles in The Cancer Genome Atlas (TCGA). We observed a mutation pattern associated with altered CpGs and APOBEC-family cytosine deaminases similar to mutation signatures derived from somatic alterations in muscle-invasive (MI) primary tumors, highlighting a major mechanism(s) contributing to cancer-associated alterations in the BCa cell line exomes. Non-silent sequence alterations were confirmed in 76 cancer-associated genes, including mutations that likely activate oncogenes TERT and PIK3CA, and alter chromatin-associated proteins (MLL3, ARID1A, CHD6 and KDM6A) and established BCa genes (TP53, RB1, CDKN2A and TSC1). We identified alterations in signaling pathways and proteins with related functions, including the PI3K/mTOR pathway, altered in 60% of lines; BRCA DNA repair, 44%; and SYNE1-SYNE2, 60%. Homozygous deletions of chromosome 9p21 are known to target the cell cycle regulators CDKN2A and CDKN2B. This loci was commonly lost in BCa cell lines and we show the deletions extended to the polyamine enzyme methylthioadenosine (MTA) phosphorylase (MTAP) in 36% of lines, transcription factor DMRTA1 (27%) and antiviral interferon epsilon (IFNE, 19%). Overall, the BCa cell line genomic aberrations were concordant with those found in BCa patient tumors. We used gene expression and copy number data to infer pathway activities for cell lines, then used the inferred pathway activities to build a predictive model of cisplatin response. When applied to platinum-treated patients gathered from TCGA, the model predicted treatment-specific response. Together, these data and analysis represent a valuable community resource to model basic tumor biology and to study

Investor Outlook: Rising from the Ashes; GSK's European Approval of Strimvelis for ADA-SCID.

Science.gov (United States)

Schimmer, Joshua; Breazzano, Steven

2016-06-01

GlaxoSmithKline's (GSK) and partner San Raffaele Telethon Institute for Gene Therapy's recent positive European approval for Strimvelis for treatment of severe combined immunodeficiency due to adenosine deaminase deficiency (ADA-SCID) represents the second EU-approved gene therapy and the first γ-retrovirus and first ex vivo gene therapy. In this article we discuss the significance and implications of this historic approval for the broader gene therapy field.

Gene therapy/bone marrow transplantation in ADA-deficient mice: roles of enzyme-replacement therapy and cytoreduction.

Science.gov (United States)

Carbonaro, Denise A; Jin, Xiangyang; Wang, Xingchao; Yu, Xiao-Jin; Rozengurt, Nora; Kaufman, Michael L; Wang, Xiaoyan; Gjertson, David; Zhou, Yang; Blackburn, Michael R; Kohn, Donald B

2012-11-01

Gene therapy (GT) for adenosine deaminase-deficient severe combined immune deficiency (ADA-SCID) can provide significant long-term benefit when patients are given nonmyeloablative conditioning and ADA enzyme-replacement therapy (ERT) is withheld before autologous transplantation of γ-retroviral vector-transduced BM CD34+ cells. To determine the contributions of conditioning and discontinuation of ERT to the therapeutic effects, we analyzed these factors in Ada gene knockout mice (Ada(-/-)). Mice were transplanted with ADA-deficient marrow transduced with an ADA-expressing γ-retroviral vector without preconditioning or after 200 cGy or 900 cGy total-body irradiation and evaluated after 4 months. In all tissues analyzed, vector copy numbers (VCNs) were 100- to 1000-fold greater in mice receiving 900 cGy compared with 200 cGy (P < .05). In mice receiving 200 cGy, VCN was similar whether ERT was stopped or given for 1 or 4 months after GT. In unconditioned mice, there was decreased survival with and without ERT, and VCN was very low to undetectable. When recipients were conditioned with 200 cGy and received transduced lineage-depleted marrow, only recipients receiving ERT (1 or 4 months) had detectable vector sequences in thymocytes. In conclusion, cytoreduction is important for the engraftment of gene-transduced HSC, and short-term ERT after GT did not diminish the capacity of gene-corrected cells to engraft and persist.

Effects of cytosine methylation on transcription factor binding sites

KAUST Repository

Medvedeva, Yulia A; Khamis, Abdullah M.; Kulakovskiy, Ivan V; Ba Alawi, Wail; Bhuyan, Md Shariful I; Kawaji, Hideya; Lassmann, Timo; Harbers, Matthias; Forrest, Alistair RR; Bajic, Vladimir B.

2014-01-01

Background: DNA methylation in promoters is closely linked to downstream gene repression. However, whether DNA methylation is a cause or a consequence of gene repression remains an open question. If it is a cause, then DNA methylation may affect

DNA methyltransferase homologue TRDMT1 in Plasmodium falciparum specifically methylates endogenous aspartic acid tRNA.

Science.gov (United States)

Govindaraju, Gayathri; Jabeena, C A; Sethumadhavan, Devadathan Valiyamangalath; Rajaram, Nivethika; Rajavelu, Arumugam

2017-10-01

In eukaryotes, cytosine methylation regulates diverse biological processes such as gene expression, development and maintenance of genomic integrity. However, cytosine methylation and its functions in pathogenic apicomplexan protozoans remain enigmatic. To address this, here we investigated the presence of cytosine methylation in the nucleic acids of the protozoan Plasmodium falciparum. Interestingly, P. falciparum has TRDMT1, a conserved homologue of DNA methyltransferase DNMT2. However, we found that TRDMT1 did not methylate DNA, in vitro. We demonstrate that TRDMT1 methylates cytosine in the endogenous aspartic acid tRNA of P. falciparum. Through RNA bisulfite sequencing, we mapped the position of 5-methyl cytosine in aspartic acid tRNA and found methylation only at C38 position. P. falciparum proteome has significantly higher aspartic acid content and a higher proportion of proteins with poly aspartic acid repeats than other apicomplexan pathogenic protozoans. Proteins with such repeats are functionally important, with significant roles in host-pathogen interactions. Therefore, TRDMT1 mediated C38 methylation of aspartic acid tRNA might play a critical role by translational regulation of important proteins and modulate the pathogenicity of the malarial parasite. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel CpG island set identifies tissue-specific methylation at developmental gene loci.

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Robert Illingworth

2008-01-01

Full Text Available CpG islands (CGIs are dense clusters of CpG sequences that punctuate the CpG-deficient human genome and associate with many gene promoters. As CGIs also differ from bulk chromosomal DNA by their frequent lack of cytosine methylation, we devised a CGI enrichment method based on nonmethylated CpG affinity chromatography. The resulting library was sequenced to define a novel human blood CGI set that includes many that are not detected by current algorithms. Approximately half of CGIs were associated with annotated gene transcription start sites, the remainder being intra- or intergenic. Using an array representing over 17,000 CGIs, we established that 6%-8% of CGIs are methylated in genomic DNA of human blood, brain, muscle, and spleen. Inter- and intragenic CGIs are preferentially susceptible to methylation. CGIs showing tissue-specific methylation were overrepresented at numerous genetic loci that are essential for development, including HOX and PAX family members. The findings enable a comprehensive analysis of the roles played by CGI methylation in normal and diseased human tissues.

Isolation and characterization of novel plant growth promoting Micrococcus sp NII-0909 and its interaction with cowpea

Digital Repository Service at National Institute of Oceanography (India)

Dastager, S.G.; Deepa, C.K.; Pandey, A.

, and 16S rRNA gene sequence. The strain exhibited the plant growthpromoting attributes of phosphate solubilization, auxin production, 1-aminocyclopropane-1-carboxylate deaminase activity, and siderophore production. It was able to solubilize (122.4 mg...

Identification of a New Uncompetitive Inhibitor of Adenosine Deaminase from Endophyte Aspergillus niger sp.

Science.gov (United States)

Zhang, Xin-Guo; Liu, Jin-Wen; Tang, Peng; Liu, Zi-Yu; Guo, Guang-Jun; Sun, Qiao-Yun; Yin, Jian-Jun

2018-05-01

Adenosine deaminase (ADA) is an enzyme widely distributed from bacteria to humans. ADA is known as a potential therapeutic target for the treatment of lymphoproliferative disorders and cancer. Endophytes are endosymbionts, often bacteria or fungi, which live within plant tissues and internal organs or intercellular space. Endophytes have a broad variety of bioactive metabolites that are used for the identification of novel natural compounds. Here, 54 morphologically distinct endophyte strains were isolated from six plants such as Peganum harmala Linn., Rheum officinale Baill., Gentiana macrophylla Pall., Radix stephaniae tetrandrae, Myrrha, and Equisetum hyemale Linn. The isolated strains were used for the search of ADA inhibitors that resulted in the identification of the strain with the highest inhibition activity, Aspergillus niger sp. Four compounds were isolated from this strain using three-step chromatography procedure, and compound 2 was determined as the compound with the highest inhibition activity of ADA. Based on the results of 1 H and 13 C NMR spectroscopies, compound 2 was identified as 3-(4-nitrophenyl)-5-phenyl isoxazole. We showed that compound 2 was a new uncompetitive inhibitor of ADA with high cytotoxic effect on HepG2 and SMCC-7721 cells (the IC 50 values were 0.347 and 0.380 mM, respectively). These results suggest that endophyte strains serve as promising sources for the identification of ADA inhibitors, and compound 2 could be an effective drug in the cancer treatment.

5-Aza-2'-deoxycytidine synergistic action with thymidine on leukemic cells and interaction of 5-aza-dCMP with dCMP deaminase

International Nuclear Information System (INIS)

Momparler, R.L.; Bartolucci, S.; Bouchard, J.; Momparler, L.F.; Raia, C.A.; Rossi, M.

1986-01-01

The authors observe a synergistic antineoplastic effect between 5-AZA-dCR and dTR on leukemia cells in culture. In order to understand the mechanism behind this interaction the authors investigate the effects of dTTP on the deamination of 5-aza-2'-deoxycytidine-5'-monophosphate (5-AZA-dCMP) by dCMP deaminase. The effects of 5-AZA-dCTP on this enzyme is also studied. The incorporation of tritium-5-AZA-Cdr into DNA of leukemic cells was performed. The amount of radioactivity incorproated into DNA was determined by trapping the cells on GF/C glass fiber filters and washing with cold TCA. It is shown that the modulation of the atieoplastic activity of deoxycytidine analogs by allosteric effectors such as dTTP may have the potential to increase the effectiveness of the chemotherapy for acute leukemia

ADENOSINE DEAMINASE ACTIVITY AND SERUM C-REACTIVE PROTEIN AS PROGNOSTIC MARKERS OF CHAGAS DISEASE SEVERITY

Directory of Open Access Journals (Sweden)

Iván Darío BRAVO-TOBAR

2015-10-01

Full Text Available SUMMARY Chagas disease is a public health problem worldwide. The availability of diagnostic tools to predict the development of chronic Chagas cardiomyopathy is crucial to reduce morbidity and mortality. Here we analyze the prognostic value of adenosine deaminase serum activity (ADA and C-reactive protein serum levels (CRP in chagasic individuals. One hundred and ten individuals, 28 healthy and 82 chagasic patients were divided according to disease severity in phase I (n = 35, II (n = 29, and III (n = 18. A complete medical history, 12-lead electrocardiogram, chest X-ray, and M-mode echocardiogram were performed on each individual. Diagnosis of Chagas disease was confirmed by ELISA and MABA using recombinant antigens; ADA was determined spectrophotometrically and CRP by ELISA. The results have shown that CRP and ADA increased linearly in relation to disease phase, CRP being significantly higher in phase III and ADA at all phases. Also, CRP and ADA were positively correlated with echocardiographic parameters of cardiac remodeling and with electrocardiographic abnormalities, and negatively with ejection fraction. CRP and ADA were higher in patients with cardiothoracic index ≥ 50%, while ADA was higher in patients with ventricular repolarization disturbances. Finally, CRP was positively correlated with ADA. In conclusion, ADA and CRP are prognostic markers of cardiac dysfunction and remodeling in Chagas disease.

Xeroderma pigmentosum complementation group C cells remove pyrimidine dimers selectively from the transcribed strand of active genes

International Nuclear Information System (INIS)

Venema, J.; van Hoffen, A.; Karcagi, V.; Natarajan, A.T.; van Zeeland, A.A.; Mullenders, L.H.

1991-01-01

The authors have measured the removal of UV-induced pyrimidine dimers from DNA fragments of the adenosine deaminase (ADA) and dihydrofolate reductase (DHFR) genes in primary normal human and xeroderma pigmentosum complementation group C (XP-C) cells. Using strand-specific probes, we show that in normal cells, preferential repair of the 5' part of the ADA gene is due to the rapid and efficient repair of the transcribed strand. Within 8 h after irradiation with UV at 10 J m-2, 70% of the pyrimidine dimers in this strand are removed. The nontranscribed strand is repaired at a much slower rate, with 30% dimers removed after 8 h. Repair of the transcribed strand in XP-C cells occurs at a rate indistinguishable from that in normal cells, but the nontranscribed strand is not repaired significantly in these cells. Similar results were obtained for the DHFR gene. In the 3' part of the ADA gene, however, both normal and XP-C cells perform fast and efficient repair of either strand, which is likely to be caused by the presence of transcription units on both strands. The factor defective in XP-C cells is apparently involved in the processing of DNA damage in inactive parts of the genome, including nontranscribed strands of active genes. These findings have important implications for the understanding of the mechanism of UV-induced excision repair and mutagenesis in mammalian cells

Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium enzyme at near-atomic resolution

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Azim, N.; Deery, E.; Warren, M. J.; Wolfenden, B. A. A.; Erskine, P.; Cooper, J. B.; Coker, A.; Wood, S. P.; Akhtar, M.

2014-01-01

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses a key early step in the biosynthesis of tetrapyrroles in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. Two near-atomic resolution structures of PBGD from B. megaterium are reported that demonstrate the time-dependent accumulation of partially oxidized forms of the cofactor, including one that possesses a tetrahedral C atom in the terminal pyrrole ring. The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form

Identification of novel Clostridium perfringens type E strains that carry an iota toxin plasmid with a functional enterotoxin gene.

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Kazuaki Miyamoto

Full Text Available Clostridium perfringens enterotoxin (CPE is a major virulence factor for human gastrointestinal diseases, such as food poisoning and antibiotic associated diarrhea. The CPE-encoding gene (cpe can be chromosomal or plasmid-borne. Recent development of conventional PCR cpe-genotyping assays makes it possible to identify cpe location (chromosomal or plasmid in type A isolates. Initial studies for developing cpe genotyping assays indicated that all cpe-positive strains isolated from sickened patients were typable by cpe-genotypes, but surveys of C. perfringens environmental strains or strains from feces of healthy people suggested that this assay might not be useful for some cpe-carrying type A isolates. In the current study, a pulsed-field gel electrophoresis Southern blot assay showed that four cpe-genotype untypable isolates carried their cpe gene on a plasmid of ∼65 kb. Complete sequence analysis of the ∼65 kb variant cpe-carrying plasmid revealed no intact IS elements and a disrupted cytosine methyltransferase (dcm gene. More importantly, this plasmid contains a conjugative transfer region, a variant cpe gene and variant iota toxin genes. The toxin genes encoded by this plasmid are expressed based upon the results of RT-PCR assays. The ∼65 kb plasmid is closely related to the pCPF4969 cpe plasmid of type A isolates. MLST analyses indicated these isolates belong to a unique cluster of C. perfringens. Overall, these isolates carrying a variant functional cpe gene and iota toxin genes represent unique type E strains.

Double-stranded-RNA-specific adenosine deaminase 1 (ADAR1) is proposed to contribute to the adaptation of equine infectious anemia virus from horses to donkeys.

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Tang, Yan-Dong; Zhang, Xiang; Na, Lei; Wang, Xue-Feng; Fu, Li-Hua; Zhu, Chun-Hui; Wang, Xiaojun; Zhou, Jian-Hua

2016-10-01

Equine infectious anemia virus (EIAV) is a member of the genus Lentivirus of the family Retroviridae. Horses are the most susceptible equids to EIAV infection and are therefore the primary hosts of this virus. In contrast, infected donkeys do not develop clinically active equine infectious anemia (EIA). This phenomenon is similar to what has been observed with HIV-1, which fails to induce AIDS in non-human primates. Interestingly, Shen et al. developed a donkey-tropic pathogenic virus strain (EIAVDV117, DV117) by serially passaging a horse-tropic pathogenic strain, EIAVLN40 (LN40), in donkeys. LN40, which was generated by passaging a field isolate in horses, displayed enhanced virulence in horses but caused no clinical symptoms in donkeys. Infection with DV117 induced acute EIA in nearly 100 % of donkeys. Genomic analysis of DV117 revealed a significantly higher frequency of A-to-G substitutions when compared to LN40. Furthermore, detailed analysis of dinucleotide editing showed that A-to-G mutations had a preference for 5'TpA and 5'ApA. These results strongly implicated the activity of the adenosine deaminase, ADAR1, in this type of mutation. Further investigation demonstrated that overexpression of donkey ADAR1 increased A-to-G mutations within the genome of EIAV. Together with our previous finding that multiple mutations in multiple genes are generated in DV117 during its adaptation from horses to donkeys, the present study suggests that ADAR1-induced A-to-G mutations occur during virus adaption to related new hosts contributing to the alteration of EIAV host tropism.

Novel germline mutation (Leu512Met) in the thyrotropin receptor gene (TSHR) leading to sporadic non-autoimmune hyperthyroidism.

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Roberts, Stephanie A; Moon, Jennifer E; Dauber, Andrew; Smith, Jessica R

2017-03-01

Primary nonautoimmune hyperthyroidism is a rare cause of neonatal hyperthyroidism. This results from an activating mutation in the thyrotropin-receptor (TSHR). It can be inherited in an autosomal dominant manner or occur sporadically as a de novo mutation. Affected individuals display a wide phenotype from severe neonatal to mild subclinical hyperthyroidism. We describe a 6-month-old boy with a de novo mutation in the TSHR gene who presented with accelerated growth, enlarging head circumference, tremor and thyrotoxicosis. Genomic DNA from the patient's and parents' peripheral blood leukocytes was extracted. Exons 9 and 10 of the TSHR gene were amplified by PCR and sequenced. Sequencing exon 10 of the TSHR gene revealed a novel heterozygous missense mutation substituting cytosine to adenine at nucleotide position 1534 in the patient's peripheral blood leukocytes. This leads to a substitution of leucine to methionine at amino acid position 512. The mutation was absent in the parents. In silico modeling by PolyPhen-2 and SIFT predicted the mutation to be deleterious. The p.Leu512Met mutation (c.1534C>A) of the TSHR gene has not been previously described in germline or somatic mutations. This case presentation highlights the possibility of mild thyrotoxicosis in affected individuals and contributes to the understanding of sporadic non-autoimmune primary hyperthyroidism.

DNMT1 is associated with cell cycle and DNA replication gene sets in diffuse large B-cell lymphoma.

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Loo, Suet Kee; Ab Hamid, Suzina Sheikh; Musa, Mustaffa; Wong, Kah Keng

2018-01-01

Dysregulation of DNA (cytosine-5)-methyltransferase 1 (DNMT1) is associated with the pathogenesis of various types of cancer. It has been previously shown that DNMT1 is frequently expressed in diffuse large B-cell lymphoma (DLBCL), however its functions remain to be elucidated in the disease. In this study, we gene expression profiled (GEP) shRNA targeting DNMT1(shDNMT1)-treated germinal center B-cell-like DLBCL (GCB-DLBCL)-derived cell line (i.e. HT) compared with non-silencing shRNA (control shRNA)-treated HT cells. Independent gene set enrichment analysis (GSEA) performed using GEPs of shRNA-treated HT cells and primary GCB-DLBCL cases derived from two publicly-available datasets (i.e. GSE10846 and GSE31312) produced three separate lists of enriched gene sets for each gene sets collection from Molecular Signatures Database (MSigDB). Subsequent Venn analysis identified 268, 145 and six consensus gene sets from analyzing gene sets in C2 collection (curated gene sets), C5 sub-collection [gene sets from gene ontology (GO) biological process ontology] and Hallmark collection, respectively to be enriched in positive correlation with DNMT1 expression profiles in shRNA-treated HT cells, GSE10846 and GSE31312 datasets [false discovery rate (FDR) 0.8) with DNMT1 expression and significantly downregulated (log fold-change <-1.35; p<0.05) following DNMT1 silencing in HT cells. These results suggest the involvement of DNMT1 in the activation of cell cycle and DNA replication in DLBCL cells. Copyright © 2017 Elsevier GmbH. All rights reserved.

Cytosine arabinoside influx and nucleoside transport sites in acute leukemia.

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Wiley, J S; Jones, S P; Sawyer, W H; Paterson, A R

1982-02-01

Although cytosine arabinoside (araC) can induce a remission in a majority of patients presenting with acute myeloblastic leukemia (AML), a minority fail to respond and moreover the drug has less effect in acute lymphoblastic leukemia (ALL). The carrier-mediated influx of araC into purified blasts from patients with AML, ALL, and acute undifferentiated leukemia (AUL) has been compared to that of normal lymphocytes and polymorphs. Blasts showed a larger mediated influx of araC than mature cells, since mean influxes for myeloblasts and lymphoblasts were 6- and 2.3-fold greater than polymorphs and lymphocytes, respectively. Also, the mean influx for myeloblasts was fourfold greater than the mean for lymphoblasts. The number of nucleoside transport sites was estimated for each cell type by measuring the equilibrium binding of [(3)H]nitrobenzylthioinosine (NBMPR), which inhibits nucleoside fluxes by binding with high affinity to specific sites on the transport mechanism. The mean binding site numbers for myeloblasts and lymphoblasts were 5- and 2.8-fold greater, respectively, than for the mature cells of the same maturation series. The mean number of NBMPR binding sites for myeloblasts was fourfold greater than for lymphoblasts. Patients with AUL were heterogeneous since blasts from some gave values within the myeloblastic range and others within the lymphoblastic range. The araC influx correlated closely with the number of NBMPR binding sites measured in the same cells on the same day. Transport parameters were measured on blasts from 15 patients with AML or AUL who were then treated with standard induction therapy containing araC. Eight patients entered complete remission, while seven failed therapy, among whom were the three patients with the lowest araC influx (myeloblasts have both higher araC transport rates and more nucleoside transport sites than lymphoblasts and this factor may contribute to the greater sensitivity of AML to this drug. AraC transport varied >10

Exploiting the pyrazolo[3,4-d]pyrimidin-4-one ring system as a useful template to obtain potent adenosine deaminase inhibitors.

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La Motta, Concettina; Sartini, Stefania; Mugnaini, Laura; Salerno, Silvia; Simorini, Francesca; Taliani, Sabrina; Marini, Anna Maria; Da Settimo, Federico; Lavecchia, Antonio; Novellino, Ettore; Antonioli, Luca; Fornai, Matteo; Blandizzi, Corrado; Del Tacca, Mario

2009-03-26

A number of pyrazolo[3,4-d]pyrimidin-4-ones bearing either alkyl or arylalkyl substituents in position 2 of the nucleus were synthesized and tested for their ability to inhibit adenosine deaminase (ADA) from bovine spleen. The 2-arylalkyl derivatives exhibited excellent inhibitory activity, showing Ki values in the nanomolar/subnanomolar range. The most active compound, 1-(4-((4-oxo-4,5-dihydropyrazolo[3,4-d]pyrimidin-2-yl)methyl)phenyl)-3-(4-(trifluoromethyl)phenyl)urea, 14d, was tested in rats with colitis induced by 2,4-dinitrobenzenesulfonic acid to assess its efficacy to attenuate bowel inflammation. The treatment with 14d induced a significant amelioration of both systemic and intestinal inflammatory alterations in animals with experimental colitis. Docking simulations of the synthesized compounds into the ADA catalytic site were also performed to rationalize the structure-activity relationships observed and to highlight the key pharmacophoric elements of these products, thus prospectively guiding the design of novel ADA inhibitors.

Antigen receptors and somatic hypermutation in B-cell chronic lymphocytic leukemia with Richter's transformation

NARCIS (Netherlands)

Smit, Laura A.; van Maldegem, Febe; Langerak, Anton W.; van der Schoot, C. Ellen; de Wit, Mireille J.; Bea, Silvia; Campo, Elias; Bende, Richard J.; van Noesel, Carel J. M.

2006-01-01

BACKGROUND AND OBJECTIVES: Activation-induced cytidine deaminase is essential for somatic hypermutation and class switch recombination of the immunoglobulin genes in B cells. It has been proposed that aberrant targeting of the somatic hypermutation machinery is instrumental in initiation and

Effect of Cytosine Arabinoside, 3-Aminobenzamide and Hydroxyurea on the frequencies of radiation-induced micronuclei and aneuploidy in human lymphocytes

International Nuclear Information System (INIS)

Cho, Yoon Hee; Kim, Yang Jee; Ha, Sung Whan; Chung, Hai Won; Kang, Chang Mo

2005-01-01

This study was carried out to examine the effect of the DNA repair inhibitors, Cytosine Arabinoside(Ara C), 3-Aminobenzamide(3AB) and Hydroxyurea(HU) on the frequencies of radiation-induced MicroNuclei(MNi) and aneuploidy. Irradiated lymphocytes(1-3Gy) were treated with DNA repair inhibitors, Ara C, 3AB and HU for 3 hours and CBMN assay - FISH technique with DNA probe for chromosome 1 and 4 was performed. The frequencies of x-ray induced MNi and aneuploidy of chromosome 1 and 4 were increased in a dose-dependent manner. Ara C, 3AB and HU enhanced the frequencies of radiation-induced MNi and the frequencies of radiation-induced aneuploidy of chromosome 1 and 4 were enhanced by HU and Ara C while no effect was observed by 3AB. The frequency of radiation-induced aneuploidy of chromosome 1 was higher than that of chromosome 4. These results suggest that there are different mechanisms involved in the formation of MNi and aneuploidy by radiation

Effect of Cytosine Arabinoside, 3-Aminobenzamide and Hydroxyurea on the frequencies of radiation-induced micronuclei and aneuploidy in human lymphocytes

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Cho, Yoon Hee; Kim, Yang Jee; Ha, Sung Whan; Chung, Hai Won [Seoul National Univ., Seoul (Korea, Republic of); Kang, Chang Mo [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2005-12-15

This study was carried out to examine the effect of the DNA repair inhibitors, Cytosine Arabinoside(Ara C), 3-Aminobenzamide(3AB) and Hydroxyurea(HU) on the frequencies of radiation-induced MicroNuclei(MNi) and aneuploidy. Irradiated lymphocytes(1-3Gy) were treated with DNA repair inhibitors, Ara C, 3AB and HU for 3 hours and CBMN assay - FISH technique with DNA probe for chromosome 1 and 4 was performed. The frequencies of x-ray induced MNi and aneuploidy of chromosome 1 and 4 were increased in a dose-dependent manner. Ara C, 3AB and HU enhanced the frequencies of radiation-induced MNi and the frequencies of radiation-induced aneuploidy of chromosome 1 and 4 were enhanced by HU and Ara C while no effect was observed by 3AB. The frequency of radiation-induced aneuploidy of chromosome 1 was higher than that of chromosome 4. These results suggest that there are different mechanisms involved in the formation of MNi and aneuploidy by radiation.

Diagnosis of tuberculosis pleurisy with adenosine deaminase (ADA): a systematic review and meta-analysis.

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Gui, Xuwei; Xiao, Heping

2014-01-01

This systematic review and meta-analysis was performed to determine accuracy and usefulness of adenosine deaminase (ADA) in diagnosis of tuberculosis pleurisy. Medline, Google scholar and Web of Science databases were searched to identify related studies until 2014. Two reviewers independently assessed quality of studies included according to standard Quality Assessment of Diagnosis Accuracy Studies (QUADAS) criteria. The sensitivity, specificity, diagnostic odds ratio and other parameters of ADA in diagnosis of tuberculosis pleurisy were analyzed with Meta-DiSC1.4 software, and pooled using the random effects model. Twelve studies including 865 tuberculosis pleurisy patients and 1379 non-tuberculosis pleurisy subjects were identified from 110 studies for this meta-analysis. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnosis odds ratio (DOR) of ADA in the diagnosis of tuberculosis pleurisy were 45.25 (95% CI 27.63-74.08), 0.86 (95% CI 0.84-0.88), 0.88 (95% CI 0.86-0.90), 6.32 (95% CI 4.83-8.26) and 0.15 (95% 0.11-0.22), respectively. The area under the summary receiver operating characteristic curve (SROC) was 0.9340. Our results demonstrate that the sensitivity and specificity of ADA are high in the diagnosis of tuberculosis pleurisy especially when ADA≥50 (U/L). Thus, ADA is a relatively sensitive and specific marker for tuberculosis pleurisy diagnosis. However, it is cautious to apply these results due to the heterogeneity in study design of these studies. Further studies are required to confirm the optimal cut-off value of ADA.

Production of phenylpyruvic acid from L-phenylalanine using an L-amino acid deaminase from Proteus mirabilis: comparison of enzymatic and whole-cell biotransformation approaches.

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Hou, Ying; Hossain, Gazi Sakir; Li, Jianghua; Shin, Hyun-Dong; Liu, Long; Du, Guocheng

2015-10-01

Phenylpyruvic acid (PPA) is an important organic acid that has a wide range of applications. In this study, the membrane-bound L-amino acid deaminase (L-AAD) gene from Proteus mirabilis KCTC 2566 was expressed in Escherichia coli BL21(DE3) and then the L-AAD was purified. After that, we used the purified enzyme and the recombinant E. coli whole-cell biocatalyst to produce PPA via a one-step biotransformation from L-phenylalanine. L-AAD was solubilized from the membrane and purified 52-fold with an overall yield of 13 %, which corresponded to a specific activity of 0.94 ± 0.01 μmol PPA min(-1)·mg(-1). Then, the biotransformation conditions for the pure enzyme and the whole-cell biocatalyst were optimized. The maximal production was 2.6 ± 0.1 g·L(-1) (specific activity of 1.02 ± 0.02 μmol PPA min(-1)·mg(-1) protein, 86.7 ± 5 % mass conversion rate, and 1.04 g·L(-1)·h(-1) productivity) and 3.3 ± 0.2 g L(-1) (specific activity of 0.013 ± 0.003 μmol PPA min(-1)·mg(-1) protein, 82.5 ± 4 % mass conversion rate, and 0.55 g·L(-1)·h(-1) productivity) for the pure enzyme and whole-cell biocatalyst, respectively. Comparative studies of the enzymatic and whole-cell biotransformation were performed in terms of specific activity, production, conversion, productivity, stability, need of external cofactors, and recycling. We have developed two eco-friendly and efficient approaches for PPA production. The strategy described herein may aid the biotransformational synthesis of other α-keto acids from their corresponding amino acids.

Prolonged Adaptive Evolution of a Defensive Gene in the Solanaceae.

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Rausher, Mark D; Huang, Jie

2016-01-01

Although plants and their natural enemies may coevolve for prolonged periods, little is known about how long individual plant defensive genes are involved in the coevolutionary process. We address this issue by examining patterns of selection on the defensive gene threonine deaminase (TD). Tomato (Solanum lycopersicum) has two copies of this gene. One performs the canonical housekeeping function in amino acid metabolism of catalyzing the first reaction in the conversion of threonine to isoleucine. The second copy functions as an antinutritive defense against lepidopteran herbivores by depleting threonine in the insect gut. Wild tobacco (Nicotiana attenuata) also contains a defensive copy. We show that a single copy of TD underwent two or three duplications near the base of the Solanaceae. One copy retains the housekeeping function, whereas a second copy evolved defensive functions. Positive selection occurred on the branch of the TD2 gene tree subtending the common ancestor of the Nicotianoideae and Solanoideae. It also occurred within the Solanoideae clade but not within the Nicotianoideae clade. Finally, it occurred on most branches leading from the common ancestor to S. lycopersicum. Based on recent calibrations of the Solanaceae phylogeny, TD2 experienced adaptive substitutions for a period of 30-50 My. We suggest that the most likely explanation for this result is fluctuating herbivore abundances: When herbivores are rare, relaxed selection increases the likelihood that slightly disadvantageous mutations will be fixed by drift; when herbivores are common, increased selection causes the evolution of compensatory adaptive mutations. Alternative explanations are also discussed. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Drought response of Mucuna pruriens (L. DC. inoculated with ACC deaminase and IAA producing rhizobacteria.

Directory of Open Access Journals (Sweden)

Aansa Rukya Saleem

Full Text Available Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a photosynthetic performance and biomass; b ACC content and ethylene emission from leaves and roots; c leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

Drought response of Mucuna pruriens (L.) DC. inoculated with ACC deaminase and IAA producing rhizobacteria.

Science.gov (United States)

Saleem, Aansa Rukya; Brunetti, Cecilia; Khalid, Azeem; Della Rocca, Gianni; Raio, Aida; Emiliani, Giovanni; De Carlo, Anna; Mahmood, Tariq; Centritto, Mauro

2018-01-01

Drought is one of the major constraints limiting agricultural production worldwide and is expected to increase in the future. Limited water availability causes significant effects to plant growth and physiology. Plants have evolved different traits to mitigate the stress imposed by drought. The presence of plant growth-promoting rhizobacteria (PGPR) could play an important role in improving plant performances and productivity under drought. These beneficial microorganisms colonize the rhizosphere of plants and increase drought tolerance by lowering ethylene formation. In the present study, we demonstrate the potential to improve the growth of velvet bean under water deficit conditions of two different strains of PGPR with ACCd (1-Aminocyclopropane-1-Carboxylate deaminase) activity isolated from rainfed farming system. We compared uninoculated and inoculated plants with PGPR to assess: a) photosynthetic performance and biomass; b) ACC content and ethylene emission from leaves and roots; c) leaf isoprene emission. Our results provided evidence that under drought conditions inoculation with PGPR containing the ACCd enzyme could improve plant growth compared to untreated plants. Ethylene emission from roots and leaves of inoculated velvet bean plants was significantly lower than uninoculated plants. Moreover, isoprene emission increased with drought stress progression and was higher in inoculated plants compared to uninoculated counterparts. These findings clearly illustrate that selected PGPR strains isolated from rainfed areas could be highly effective in promoting plant growth under drought conditions by decreasing ACC and ethylene levels in plants.

A case of red-cell adenosine deaminase overproduction associated with hereditary hemolytic anemia found in Japan.

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Miwa, S; Fujii, H; Matsumoto, N; Nakatsuji, T; Oda, S; Asano, H; Asano, S

1978-01-01

A case of red cell adenosine deaminase (ADA) overproduction associated with hereditary hemolytic anemia is reported here. This appears to be the second report. Proband is a 38-year-old Japanese male who had hemoglobin, 15.8 g/100 ml; reticulocyte count, 4.5%; serum indirect bilirubin, 4.9 mg/100 ml; 51Cr-labeled red cell half-life, 12 days; red cells showed moderate stomatocytosis. His red cell ADA activity showed 40-fold increase while that of the mother showed 4-fold increase. The mother was hematologically normal. The father had a normal enzyme activity. The proband and the mother showed slightly high serum uric acid levels. The proband's red cell showed: ATP, 628 nmoles/ml (normal, 1,010--1,550); adenine nucleotide pool, 46% of the normal mean; 2,3-diphosphoglycerate content, 3,782 nmoles/ml (normal 4,170--5,300); increased oxygen affinity of hemoglobin, P50 of intact erythrocytes being 21.8 mmHg (normal, 24.1--26.1). Red cell glycolytic intermediates in the proband were low in general, and the rate of lactate production was low. Kinetic studies using crude hemolysate revealed a normal Km for adenosine, normal electrophoretic mobility but slightly abnormal pH curve and slightly low utilization of 2-deoxyadenosine. The ADA activity of lymphocytes was nearly normal.

Differential DNA methylation may contribute to temporal and spatial regulation of gene expression and the development of mycelia and conidia in entomopathogenic fungus Metarhizium robertsii.

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Li, Wanzhen; Wang, Yulong; Zhu, Jianyu; Wang, Zhangxun; Tang, Guiliang; Huang, Bo

2017-03-01

Conidia and mycelia are two important developmental stages in the asexual life cycle of entomopathogenic fungus Metarhizium. Despite the crucial role that DNA methylation plays in many biological processes, its role in regulation of gene expression and development in fungi is not yet fully understood. We performed genome-wide analysis of DNA methylation patterns of an M. robertsii strain with single base pair resolution. Specifically, we examined for changes in methylation patterns between the conidia and mycelia stages. The results showed that approximately 0.38 % of cytosines are methylated in conidia, which is lower than the DNA methylation level (0.42 %) in mycelia. We found that DNA methylation undergoes genome-wide reprogramming during fungal development in M. robertsii. 132 differentially methylated regions (DMRs), which were mostly distributed in gene regions, were identified. KEGG analysis revealed that the DMR-associated genes belong to metabolic pathways. Intriguingly, in contrast to most other eukaryotes, promoter activities in M. robertsii seemed differentially modulated by DNA methylation levels. We found that transcription tended to be enhanced in genes with moderate promoter methylation, while gene expression was decreased in genes with high or low promoter methylation. Copyright © 2017 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

Shotgun Bisulfite Sequencing of the Betula platyphylla Genome Reveals the Tree’s DNA Methylation Patterning

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Chang Su

2014-12-01

Full Text Available DNA methylation plays a critical role in the regulation of gene expression. Most studies of DNA methylation have been performed in herbaceous plants, and little is known about the methylation patterns in tree genomes. In the present study, we generated a map of methylated cytosines at single base pair resolution for Betula platyphylla (white birch by bisulfite sequencing combined with transcriptomics to analyze DNA methylation and its effects on gene expression. We obtained a detailed view of the function of DNA methylation sequence composition and distribution in the genome of B. platyphylla. There are 34,460 genes in the whole genome of birch, and 31,297 genes are methylated. Conservatively, we estimated that 14.29% of genomic cytosines are methylcytosines in birch. Among the methylation sites, the CHH context accounts for 48.86%, and is the largest proportion. Combined transcriptome and methylation analysis showed that the genes with moderate methylation levels had higher expression levels than genes with high and low methylation. In addition, methylated genes are highly enriched for the GO subcategories of binding activities, catalytic activities, cellular processes, response to stimulus and cell death, suggesting that methylation mediates these pathways in birch trees.

Mixed Inhibition of Adenosine Deaminase Activity by 1,3-Dinitrobenzene: A Model for Understanding Cell-Selective Neurotoxicity in Chemically-Induced Energy Deprivation Syndromes in Brain

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Wang, Yipei; Liu, Xin; Schneider, Brandon; Zverina, Elaina A.; Russ, Kristen; Wijeyesakere, Sanjeeva J.; Fierke, Carol A.; Richardson, Rudy J.; Philbert, Martin A.

2012-01-01

Astrocytes are acutely sensitive to 1,3-dinitrobenzene (1,3-DNB) while adjacent neurons are relatively unaffected, consistent with other chemically-induced energy deprivation syndromes. Previous studies have investigated the role of astrocytes in protecting neurons from hypoxia and chemical injury via adenosine release. Adenosine is considered neuroprotective, but it is rapidly removed by extracellular deaminases such as adenosine deaminase (ADA). The present study tested the hypothesis that ADA is inhibited by 1,3-DNB as a substrate mimic, thereby preventing adenosine catabolism. ADA was inhibited by 1,3-DNB with an IC50 of 284μM, Hill slope, n = 4.8 ± 0.4. Native gel electrophoresis showed that 1,3-DNB did not denature ADA. Furthermore, adding Triton X-100 (0.01–0.05%, wt/vol), Nonidet P-40 (0.0015–0.0036%, wt/vol), or bovine serum albumin (0.05 mg/ml or changing [ADA] (0.2 and 2nM) did not substantially alter the 1,3-DNB IC50 value. Likewise, dynamic light scattering showed no particle formation over a (1,3-DNB) range of 149–1043μM. Kinetics revealed mixed inhibition with 1,3-DNB binding to ADA (KI = 520 ± 100μM, n = 1 ± 0.6) and the ADA-adenosine complex (KIS = 262 ± 7μM, n = 6 ± 0.6, indicating positive cooperativity). In accord with the kinetics, docking predicted binding of 1,3-DNB to the active site and three peripheral sites. In addition, exposure of DI TNC-1 astrocytes to 10–500μM 1,3-DNB produced concentration-dependent increases in extracellular adenosine at 24 h. Overall, the results demonstrate that 1,3-DNB is a mixed inhibitor of ADA and may thus lead to increases in extracellular adenosine. The finding may provide insights to guide future work on chemically-induced energy deprivation. PMID:22106038

Promoter activity of polypyrimidine tract-binding protein genes of potato responds to environmental cues.

Science.gov (United States)

Butler, Nathaniel M; Hannapel, David J

2012-12-01

Polypyrimidine tract-binding (PTB) proteins are RNA-binding proteins that target specific RNAs for post-transcriptional processing by binding cytosine/uracil motifs. PTBs have established functions in a range of RNA processes including splicing, translation, stability and long-distance transport. Six PTB-like genes identified in potato have been grouped into two clades based on homology to other known plant PTBs. StPTB1 and StPTB6 are closely related to a PTB protein discovered in pumpkin, designated CmRBP50, and contain four canonical RNA-recognition motifs. CmRBP50 is expressed in phloem tissues and functions as the core protein of a phloem-mobile RNA/protein complex. Sequence from the potato genome database was used to clone the upstream sequence of these two PTB genes and analyzed to identify conserved cis-elements. The promoter of StPTB6 was enriched for regulatory elements for light and sucrose induction and defense. Upstream sequence of both PTB genes was fused to β-glucuronidase and monitored in transgenic potato lines. In whole plants, the StPTB1 promoter was most active in leaf veins and petioles, whereas StPTB6 was most active in leaf mesophyll. Both genes are active in new tubers and tuber sprouts. StPTB6 expression was induced in stems and stolon sections in response to sucrose and in leaves or petioles in response to light, heat, drought and mechanical wounding. These results show that CmRBP50-like genes of potato exhibit distinct expression patterns and respond to both developmental and environmental cues.

Weak Organic Acids Decrease Borrelia burgdorferi Cytoplasmic pH, Eliciting an Acid Stress Response and Impacting RpoN- and RpoS-Dependent Gene Expression

Directory of Open Access Journals (Sweden)

Daniel P. Dulebohn

2017-09-01

Full Text Available The spirochete Borrelia burgdorferi survives in its tick vector, Ixodes scapularis, or within various hosts. To transition between and survive in these distinct niches, B. burgdorferi changes its gene expression in response to environmental cues, both biochemical and physiological. Exposure of B. burgdorferi to weak monocarboxylic organic acids, including those detected in the blood meal of fed ticks, decreased the cytoplasmic pH of B. burgdorferi in vitro. A decrease in the cytoplasmic pH induced the expression of genes encoding enzymes that have been shown to restore pH homeostasis in other bacteria. These include putative coupled proton/cation exchangers, a putative Na+/H+ antiporter, a neutralizing buffer transporter, an amino acid deaminase and a proton exporting vacuolar-type VoV1 ATPase. Data presented in this report suggested that the acid stress response triggered the expression of RpoN- and RpoS-dependent genes including important virulence factors such as outer surface protein C (OspC, BBA66, and some BosR (Borreliaoxidative stress regulator-dependent genes. Because the expression of virulence factors, like OspC, are so tightly connected by RpoS to general cellular stress responses and cell physiology, it is difficult to separate transmission-promoting conditions in what is clearly a multifactorial and complex regulatory web.

Ocular findings associated with a Cys39Arg mutation in the Norrie disease gene.

Science.gov (United States)

Joos, K M; Kimura, A E; Vandenburgh, K; Bartley, J A; Stone, E M

1994-12-01

To diagnose the carriers and noncarriers in a family affected with Norrie disease based on molecular analysis. Family members from three generations, including one affected patient, two obligate carriers, one carrier identified with linkage analysis, one noncarrier identified with linkage analysis, and one female family member with indeterminate carrier status, were examined clinically and electrophysiologically. Linkage analysis had previously failed to determine the carrier status of one female family member in the third generation. Blood samples were screened for mutations in the Norrie disease gene with single-strand conformation polymorphism analysis. The mutation was characterized by dideoxy-termination sequencing. Ophthalmoscopy and electroretinographic examination failed to detect the carrier state. The affected individuals and carriers in this family were found to have a transition from thymidine to cytosine in the first nucleotide of codon 39 of the Norrie disease gene, causing a cysteine-to-arginine mutation. Single-strand conformation polymorphism analysis identified a patient of indeterminate status (by linkage) to be a noncarrier of Norrie disease. Ophthalmoscopy and electroretinography could not identify carriers of this Norrie disease mutation. Single-strand conformation polymorphism analysis was more sensitive and specific than linkage analysis in identifying carriers in this family.

Unedited Version

Indian Academy of Sciences (India)

58

Identification of RNA-specific adenosine deaminase 1 (ADAR1) gene results in ... youth male patient with a deleterious substitution of Leu1052Pro of ADAR1 ... reaction system contained 14.75 µl double-distilled water, 2.5 µl 10X buffer, 2 µl.

Analysis of DNA methylation related to rice adult plant resistance to bacterial blight based on methylation-sensitive AFLP (MSAP) analysis.

Science.gov (United States)

Sha, A H; Lin, X H; Huang, J B; Zhang, D P

2005-07-01

DNA methylation is known to play an important role in the regulation of gene expression in eukaryotes. The rice cultivar Wase Aikoku 3 becomes resistant to the blight pathogen Xanthomonas oryzae pv. oryzae at the adult stage. Using methylation-sensitive amplified polymorphism (MSAP) analysis, we compared the patterns of cytosine methylation in seedlings and adult plants of the rice cultivar Wase Aikoku 3 that had been inoculated with the pathogen Xanthomonas oryzae pv. oryzae, subjected to mock inoculation or left untreated. In all, 2000 DNA fragments, each representing a recognition site cleaved by either or both of two isoschizomers, were amplified using 60 pairs of selective primers. A total of 380 sites were found to be methylated. Of these, 45 showed differential cytosine methylation among the seedlings and adult plants subjected to different treatments, and overall levels of methylation were higher in adult plants than in seedlings. All polymorphic fragments were sequenced, and six showed homology to genes that code for products of known function. Northern analysis of three fragments indicated that their expression varied with methylation pattern, with hypermethylation being correlated with repression of transcription, as expected. The results suggest that significant differences in cytosine methylation exist between seedlings and adult plants, and that hypermethylation or hypomethylation of specific genes may be involved in the development of adult plant resistance (APR) in rice plants.

Ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) activities in prostate cancer patients: influence of Gleason score, treatment and bone metastasis.

Science.gov (United States)

Battisti, Vanessa; Maders, Liési D K; Bagatini, Margarete D; Battisti, Iara E; Bellé, Luziane P; Santos, Karen F; Maldonado, Paula A; Thomé, Gustavo R; Schetinger, Maria R C; Morsch, Vera M

2013-04-01

The relation between adenine nucleotides and cancer has already been described in literature. Considering that the enzymes ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) act together to control nucleotide levels, we aimed to investigate the role of these enzymes in prostate cancer (PCa). E-NPP and ADA activities were determined in serum and platelets of PCa patients and controls. We also verified the influence of the Gleason score, bone metastasis and treatment in the enzyme activities. Platelets and serum E-NPP activity increased, whereas ADA activity in serum decreased in PCa patients. In addition, Gleason score, metastasis and treatment influenced E-NPP and ADA activities. We may propose that E-NPP and ADA are involved in the development of PCa. Moreover, E-NPP and ADA activities are modified in PCa patients with distinct Gleason score, with bone metastasis, as well as in patients under treatment. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Analysis of serum adenosine deaminase (ADA) and ADA1 and ADA2 isoenzyme activities in HIV positive and HIV-HBV co-infected patients.

Science.gov (United States)

Khodadadi, Iraj; Abdi, Mohammad; Ahmadi, Abbas; Wahedi, Mohammad Saleh; Menbari, Shahoo; Lahoorpour, Fariba; Rahbari, Rezgar

2011-08-01

To determine adenosine deaminase (ADA) activity as a possible diagnostic marker in HIV and HIV-HBV co-infected patients. Blood samples were collected from 72 healthy, 33 HIV positive and 30 HIV-HBV co-infected subjects. Blood CD4+ cell count was recorded and serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total ADA, and ADA1 and ADA2 isoenzyme activities were determined. Serum ALT, AST, total ADA and ADA2 isoenzyme activities were significantly higher in HIV positive and HIV-HBV co-infected groups compare to the control (pADA activities (R(2)=0.589, pADA was significantly increased in HIV and HIV-HBV co-infections. Therefore, because of its low cost and simplicity to perform, ADA activity might be considered as a useful diagnostic tool among the other markers in these diseases. Copyright © 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Inherited variants affecting RNA editing may contribute to ovarian cancer susceptibility

DEFF Research Database (Denmark)

Permuth, Jennifer B; Reid, Brett; Earp, Madalene

2016-01-01

RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single nucleo......, including rs1127313 (G/A), a SNP in the 3' untranslated region. In summary, germline variation involving RNA editing genes may influence EOC susceptibility, warranting further investigation of inherited and acquired alterations affecting RNA editing.......RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single...... nucleotide polymorphisms (SNPs) in ADAR genes modify EOC susceptibility, potentially by altering ovarian tissue gene expression. Using directly genotyped and imputed data from 10,891 invasive EOC cases and 21,693 controls, we evaluated the associations of 5,303 SNPs in ADAD1, ADAR, ADAR2, ADAR3, and SND1...

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.

DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease

International Nuclear Information System (INIS)

Dupuy, Aurélie; Sarasin, Alain

2015-01-01

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

Genomic change, retrotransposon mobilization and extensive cytosine methylation alteration in Brassica napus introgressions from two intertribal hybridizations.

Science.gov (United States)

Zhang, Xueli; Ge, Xianhong; Shao, Yujiao; Sun, Genlou; Li, Zaiyun

2013-01-01

Hybridization and introgression represent important means for the transfer and/or de novo origination of traits and play an important role in facilitating speciation and plant breeding. Two sets of introgression lines in Brassica napus L. were previously established by its intertribal hybridizations with two wild species and long-term selection. In this study, the methods of amplified fragment length polymorphisms (AFLP), sequence-specific amplification polymorphism (SSAP) and methylation-sensitive amplified polymorphism (MSAP) were used to determine their genomic change, retrotransposon mobilization and cytosine methylation alteration in these lines. The genomic change revealed by the loss or gain of AFLP bands occurred for ∼10% of the total bands amplified in the two sets of introgressions, while no bands specific for wild species were detected. The new and absent SSAP bands appeared for 9 out of 11 retrotransposons analyzed, with low frequency of new bands and their total percentage of about 5% in both sets. MSAP analysis indicated that methylation changes were common in these lines (33.4-39.8%) and the hypermethylation was more frequent than hypomethylation. Our results suggested that certain extents of genetic and epigenetic alterations were induced by hybridization and alien DNA introgression. The cryptic mechanism of these changes and potential application of these lines in breeding were also discussed.

Generation and analysis of cDNA library from lipopolysaccharide ...

African Journals Online (AJOL)

These immune-related genes include cytidine deaminase, ferritin, nonmuscle myosin essential light chain, cytochrome c oxidase subunit I, CD63 antigen-like protein and lysosomal-associated transmembrane protein. This study may contribute to the understanding of the immune mechanism of gastropod abalone Haliotis ...

The yield of fission neutron-induced chromatid aberrations in G[sub 2]-stage human lymphocytes: effect of caffeine, hydroxyurea and cytosine arabinoside post-irradiation

Energy Technology Data Exchange (ETDEWEB)

Antoccia, A.; Tanzarella, C. (La Sapienza Univ., Rome (Italy)); Palitti, F. (Tuscia Univ., Viterbo (Italy) La Sapienza Univ., Rome (Italy)); Raggi, T. (Tuscia Univ., Viterbo (Italy)); Catena, C. (ENEA, Casaccia (Italy). Centro Ricerche Energia)

1992-11-01

To evaluate the influence of inhibitors of DNA synthesis/repair on the yield of chromosomal aberrations in the G[sub 2] phase of the cell cycle, whole-blood cultures of human lymphocytes were exposed to various doses of fission neutrons or X-rays and treated post-irradiation during the last 2.45 h before harvesting, with 5mM hydroxyurea (HU) and 0.05 mM cytosine arabinoside (ara-C). The presence of caffeine and HU strongly potentiated the yield of chromatid-type aberrations induced by both neutrons and X-rays. No potentiating effect, except at the highest dose of neutrons, was observed when irradiated cells were subsequently treated with ara-C. In addition, neutron-induced mitotic delay was shortened by treatment with caffeine, mainly within the first 2 h after irradiation. (Author).

Novel germline mutation (Leu512Met) in the thyrotropin receptor gene (TSHR) leading to sporadic non-autoimmune hyperthyroidism

Science.gov (United States)

Roberts, Stephanie A.; Moon, Jennifer E.; Dauber, Andrew; Smith, Jessica R.

2018-01-01

Background Primary nonautoimmune hyperthyroidism is a rare cause of neonatal hyperthyroidism. This results from an activating mutation in the thyrotropin-receptor (TSHR). It can be inherited in an autosomal dominant manner or occur sporadically as a de novo mutation. Affected individuals display a wide phenotype from severe neonatal to mild subclinical hyperthyroidism. We describe a 6-month-old boy with a de novo mutation in the TSHR gene who presented with accelerated growth, enlarging head circumference, tremor and thyrotoxicosis. Methods Genomic DNA from the patient’s and parents’ peripheral blood leukocytes was extracted. Exons 9 and 10 of the TSHR gene were amplified by PCR and sequenced. Results Sequencing exon 10 of the TSHR gene revealed a novel heterozygous missense mutation substituting cytosine to adenine at nucleotide position 1534 in the patient’s peripheral blood leukocytes. This leads to a substitution of leucine to methionine at amino acid position 512. The mutation was absent in the parents. In silico modeling by PolyPhen-2 and SIFT predicted the mutation to be deleterious. Conclusions The p.Leu512Met mutation (c.l534C>A) of the TSHR gene has not been previously described in germline or somatic mutations. This case presentation highlights the possibility of mild thyrotoxicosis in affected individuals and contributes to the understanding of sporadic non-autoimmune primary hyperthyroidism. PMID:28195550

Alterations in the K-ras and p53 genes in rat lung tumors

Energy Technology Data Exchange (ETDEWEB)

Belinsky, S.A.; Swafford, D.S.; Finch, G.L.; Mitchell, C.E. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States)] [and others

1997-06-01

Activation of the K-ras protooncogene and inactivation of the p53 tumor suppressor gene are events common to many types of human cancers. Molecular epidemiology studies have associated mutational profiles in these genes with specific exposures. The purpose of this paper is to review investigations that have examined the role of the K-ras and p53 genes in lung tumors induced in the F344 rat by mutagenic and nonmutagenic exposures. Mutation profiles within the K-ras and p53 genes, if present in rat lung tumors, would help to define some of the molecular mechanisms underlying cancer induction by various environmental agents. Pulmonary adenocarcinomas or squamous cell carcinomas were induced by tetranitromethane (TNM), 4-methylnitrosamino-1-(3-pyridyl)-1-butanone (NNK), beryllium metal, plutonium-239, X-ray, diesel exhaust, or carbon black. These agents were chosen because the tumors they produced could arise via different types of DNA damage. Mutation of the K-ras gene was determined by approaches that included DNA transfection, direct sequencing, mismatch hybridization, and restriction fragment length polymorphism analysis. The frequency for mutation of the K-ras gene was exposure dependent. The transition mutations formed could have been derived from deamination of cytosine. Alteration in the p53 gene was assessed by immunohistochemical analysis for p53 protein and single-strand conformation polymorphism (SSCP) analysis of exons 4 to 9. None of the 93 adenocarinomas examined was immunoreactive toward the anti-p53 antibody CM1. In contrast, 14 of 71 squamous cell carcinomas exhibited nuclear p53 immunoreactivity with no correlation to type of exposure. However, SSCP analysis only detected mutations in 2 of 14 squamous cell tumors that were immunoreactive, suggesting that protein stabilization did not stem from mutations within the p53 gene. Thus, the p53 gene does not appear to be involved in the genesis of most rat lung tumors. 2 figs., 2 tabs., 48 refs.

Can pleural adenosine deaminase (ADA) levels in pleural tuberculosis predict the presence of pulmonary tuberculosis? A CT analysis.

Science.gov (United States)

Koh, Myung Je; Lee, In Jae; Kim, Joo-Hee

2016-06-01

To assess the relationship between imaging features of pulmonary tuberculosis at computed tomography (CT) and adenosine deaminase (ADA) values via pleural fluid analysis in patients with pleural tuberculosis. This retrospective study enrolled 60 patients who underwent fluid analysis for ADA and chest CT and were diagnosed with tuberculosis by culture or polymerase chain reaction of pleural fluid and sputum. The presence of centrilobular nodules, consolidation, cavitation, and mediastinal lymphadenopathy at CT were evaluated. The relationship between ADA values and the pattern of pulmonary involvement of tuberculosis was analysed. Pulmonary involvement was seen in 42 of the 60 patients. A centrilobular nodular pattern was seen in 37 and consolidation in 22. In 17 patients, both findings were identified. A centrilobular nodular pattern was more common than consolidation or cavitary lesions. When ADA values were high, pulmonary involvement was more frequent (p=0.002). Comparing low and high ADA groups using an obtained cut-off value of 80 IU/l, the high group had more frequent pulmonary involvement (pADA values had a higher probability of manifesting pulmonary tuberculosis. High ADA values may help predict contagious pleuroparenchymal tuberculosis. The most common pulmonary involvement of tuberculous pleurisy showed a centrilobular nodular pattern. Copyright © 2016 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Cerebrospinal fluid adenosine deaminase activity: A complimentary tool in the early diagnosis of tuberculous meningitis

Directory of Open Access Journals (Sweden)

Taori Girdhar M

2006-03-01

Full Text Available Abstract Background Tuberculous meningitis (TBM is the commonest form of neurotuberculosis caused by Mycobacterium tuberculosis bacilli (MTB. The diagnosis of TBM is often difficult. A reliable, cost-effective and rapid diagnostic test, which can be performed in any standard pathology laboratory, could be of help in the diagnosis of TBM. In the present study we measured the adenosine deaminase (ADA activity in cerebrospinal fluid (CSF of TBM and non-TBM patients. Method ADA activity in CSF was determined according to a method based on the Berthlot reaction, which is the formation of a colored indophenol complex from ammonia liberated from adenosine, and quantified spectrophotometrically. Results The CSF ADA activity from TBM patients was compared with CSF ADA from non-TBM infectious meningitis patients, and from patients with non-infectious neurological disorders. The mean CSF ADA activity was found to be significantly higher in CSF of TBM patients, 14.31 ± 3.87 (2.99–26.94, mean ± SD with range, than in the CSF from non-TBM infectious meningitis, 9.25 ± 2.14 (4.99–13.96 and from the non-infectious neurological disorders group, 2.71 ± 1.96 (0.00–7.68, P Conclusion This study demonstrated that ADA activity in the CSF of TBM patients, using a cut-off value 11.39 U/L/min, can be useful for the early differential diagnosis of TBM. This test can be performed in any pathology laboratory where more sophisticated methods are not available.

Cerebrospinal fluid adenosine deaminase levels as a diagnostic marker in tuberculous meningitis in adult Nepalese patients

Directory of Open Access Journals (Sweden)

Anil Chander

2013-02-01

Full Text Available Objective: To study the cerebrospinal fluid (CSF adenosine deaminase (ADA levels in tuberculous meningitis (TBM and non-TBM -viral meningitis cases and to determine its diagnostic significance as a biochemical marker of TBM infection.Methods: The study population comprised two different patient groups. TBM - group I - 28 cases and non-TBM-viral meningitis - 22 cases. These were enrolled consecutively in the study and CSF specimens were collected from them. ADA estimation was carried out by spectrophotometry.Results: ADA levels (mean依 SD in the TBM and non-TBM groups were 16.46依6.24 U/L and 5.13依2.96 U/L, respectively (highly significant P10 IU/L, the test showed a good sensitivity of 82.14% (95% CI 64.41-92.12 and a high specificity of 90.91% (95% CI 72.19-97.47. Positive and negative predictive value and positive and negative likelihood ratios and accuracy of the test in TBM cases were 92% (95% CI 75.03-97.77, 80% (95% CI 60.86-91.13, 9.03 (95% CI 2.38- 34.25, 0.19 (95% CI 0.09-0.44 and 86%, respectively.Conclusion: CSF ADA levels are elevated in the TBM cases as compared to the non-TBM - viral meningitis cases with a good sensitivity and a high specificity. It is a simple and inexpensive diagnostic adjunctive test in the rapid and early diagnosis of TBM.

Assessing the fidelity of ancient DNA sequences amplified from nuclear genes

DEFF Research Database (Denmark)

Binladen, Jonas; Wiuf, Carsten Henrik; Gilbert, M. Thomas P.

2006-01-01

To date, the field of ancient DNA has relied almost exclusively on mitochondrial DNA (mtDNA) sequences. However, a number of recent studies have reported the successful recovery of ancient nuclear DNA (nuDNA) sequences, thereby allowing the characterization of genetic loci directly involved...... in phenotypic traits of extinct taxa. It is well documented that postmortem damage in ancient mtDNA can lead to the generation of artifactual sequences. However, as yet no one has thoroughly investigated the damage spectrum in ancient nuDNA. By comparing clone sequences from 23 fossil specimens, recovered from...... adenine), respectively. Type 2 transitions are by far the most dominant and increase relative to those of type 1 with damage load. The results suggest that the deamination of cytosine (and 5-methyl cytosine) to uracil (and thymine) is the main cause of miscoding lesions in both ancient mtDNA and nu...

A phase I study of hydralazine to demethylate and reactivate the expression of tumor suppressor genes

International Nuclear Information System (INIS)

Zambrano, Pilar; Sandoval, Karina; Trejo-Becerril, Catalina; Chanona-Vilchis, Jose; Duenas-González, Alfonso; Segura-Pacheco, Blanca; Perez-Cardenas, Enrique; Cetina, Lucely; Revilla-Vazquez, Alma; Taja-Chayeb, Lucía; Chavez-Blanco, Alma; Angeles, Enrique; Cabrera, Gustavo

2005-01-01

The antihypertensive compound hydralazine is a known demethylating agent. This phase I study evaluated the tolerability and its effects upon DNA methylation and gene reactivation in patients with untreated cervical cancer. Hydralazine was administered to cohorts of 4 patients at the following dose levels: I) 50 mg/day, II) 75 mg/day, III) 100 mg/day and IV) 150 mg/day. Tumor biopsies and peripheral blood samples were taken the day before and after treatment. The genes APC, MGMT; ER, GSTP1, DAPK, RARβ, FHIT and p16 were evaluated pre and post-treatment for DNA promoter methylation and gene expression by MSP (Methylation-Specific PCR) and RT-PCR respectively in each of the tumor samples. Methylation of the imprinted H19 gene and the 'normally methylated' sequence clone 1.2 was also analyzed. Global DNA methylation was analyzed by capillary electrophoresis and cytosine extension assay. Toxicity was evaluated using the NCI Common Toxicity Criteria. Hydralazine was well tolerated. Toxicities were mild being the most common nausea, dizziness, fatigue, headache and palpitations. Overall, 70% of the pretreatment samples and all the patients had at least one methylated gene. Rates of demethylation at the different dose levels were as follows: 50 mg/day, 40%; 75 mg/day, 52%, 100 mg/day, 43%, and 150 mg/day, 32%. Gene expression analysis showed only 12 informative cases, of these 9 (75%) re-expressed the gene. There was neither change in the methylation status of H19 and clone 1.2 nor changes in global DNA methylation. Hydralazine at doses between 50 and 150 mg/day is well tolerated and effective to demethylate and reactivate the expression of tumor suppressor genes without affecting global DNA methylation

A Genome-Scale Investigation of How Sequence, Function, and Tree-Based Gene Properties Influence Phylogenetic Inference.

Science.gov (United States)

Shen, Xing-Xing; Salichos, Leonidas; Rokas, Antonis

2016-09-02

Molecular phylogenetic inference is inherently dependent on choices in both methodology and data. Many insightful studies have shown how choices in methodology, such as the model of sequence evolution or optimality criterion used, can strongly influence inference. In contrast, much less is known about the impact of choices in the properties of the data, typically genes, on phylogenetic inference. We investigated the relationships between 52 gene properties (24 sequence-based, 19 function-based, and 9 tree-based) with each other and with three measures of phylogenetic signal in two assembled data sets of 2,832 yeast and 2,002 mammalian genes. We found that most gene properties, such as evolutionary rate (measured through the percent average of pairwise identity across taxa) and total tree length, were highly correlated with each other. Similarly, several gene properties, such as gene alignment length, Guanine-Cytosine content, and the proportion of tree distance on internal branches divided by relative composition variability (treeness/RCV), were strongly correlated with phylogenetic signal. Analysis of partial correlations between gene properties and phylogenetic signal in which gene evolutionary rate and alignment length were simultaneously controlled, showed similar patterns of correlations, albeit weaker in strength. Examination of the relative importance of each gene property on phylogenetic signal identified gene alignment length, alongside with number of parsimony-informative sites and variable sites, as the most important predictors. Interestingly, the subsets of gene properties that optimally predicted phylogenetic signal differed considerably across our three phylogenetic measures and two data sets; however, gene alignment length and RCV were consistently included as predictors of all three phylogenetic measures in both yeasts and mammals. These results suggest that a handful of sequence-based gene properties are reliable predictors of phylogenetic signal

Levels of HIV1 gp120 3D B-cell epitopes mutability and variability: searching for possible vaccine epitopes.

Science.gov (United States)

Khrustalev, Vladislav Victorovich

2010-01-01

We used a DiscoTope 1.2 (http://www.cbs.dtu.dk/services/DiscoTope/), Epitopia (http://epitopia.tau.ac.il/) and EPCES (http://www.t38.physik.tu-muenchen.de/programs.htm) algorithms to map discontinuous B-cell epitopes in HIV1 gp120. The most mutable nucleotides in HIV genes are guanine (because of G to A hypermutagenesis) and cytosine (because of C to U and C to A mutations). The higher is the level of guanine and cytosine usage in third (neutral) codon positions and the lower is their level in first and second codon positions of the coding region, the more stable should be an epitope encoded by this region. We compared guanine and cytosine usage in regions coding for five predicted 3D B-cell epitopes of gp120. To make this comparison we used GenBank resource: 385 sequences of env gene obtained from ten HIV1-infected individuals were studied (http://www.barkovsky.hotmail.ru/Data/Seqgp120.htm). The most protected from nonsynonymous nucleotide mutations of guanine and cytosine 3D B-cell epitope is situated in the first conserved region of gp120 (it is mapped from 66th to 86th amino acid residue). We applied a test of variability to confirm this finding. Indeed, the less mutable predicted B-cell epitope is the less variable one. MEGA4 (standard PAM matrix) was used for the alignments and "VVK Consensus" algorithm (http://www.barkovsky.hotmail.ru) was used for the calculations.

DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease.

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Dupuy, Aurélie; Sarasin, Alain

2015-06-01

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. Copyright © 2014 Elsevier B.V. All rights reserved.

Cytosine-assisted synthesis of gold nanochains and gold nanoflowers for the construction of a microperoxidase-11 based amperometric biosensor for hydrogen peroxide

International Nuclear Information System (INIS)

Zhang, Qian-Li; Zhou, Dan-Ling; Wang, Ai-Jun; Qin, Su-Fang; Feng, Jiu-Ju; Li, Yong-Fang

2014-01-01

A simple method was developed for synthesis of network-like gold nanochains and gold nanoflowers in the presence of cytosine by reduction of tetrachloroauric acid with sodium borohydride and ascorbic acid, respectively. The resulting gold nanocrystals were coated with microperoxidase-11 via electrostatic interactions. Electrodes modified with protein-coated gold nanochains or nanoflowers display well-defined and quasi reversible redox peaks and enhanced high electrocatalytic activity toward the reduction of H 2 O 2 that is due to direct electron transfer to the protein. The effects were exploited for the amperometric detection of H 2 O 2 with a linear response from 0.5 μM to 0.13 mM (for the gold nanochains) and from 1.0 μM to 0.11 mM (for the gold nanoflowers), respectively. The sensor shows lower detection limit and faster response time than sensors based on the use of spherical gold nanoparticles. (author)

Infraspecific DNA methylation polymorphism in cotton (Gossypium hirsutum L.).

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Keyte, Anna L; Percifield, Ryan; Liu, Bao; Wendel, Jonathan F

2006-01-01

Cytosine methylation is important in the epigenetic regulation of gene expression and development in plants and has been implicated in silencing duplicate genes after polyploid formation in several plant groups. Relatively little information exists, however, on levels and patterns of methylation polymorphism (MP) at homologous loci within species. Here we explored the levels and patterns of methylation-polymorphism diversity at CCGG sites within allotetraploid cotton, Gossypium hirsutum, using a methylation-sensitive amplified fragment length polymorphism screen and a selected set of 20 G. hirsutum accessions for which we have information on genetic polymorphism levels and relationships. Methylation and MP exist at high levels within G. hirsutum: of 150 HpaII/MspI sites surveyed, 48 were methylated at the inner cytosine (32%) and 32 of these were polymorphic (67%). Both these values are higher than comparable measures of genetic diversity using restriction fragment length polymorphisms. The high percentage of methylation-polymorphic sites and potential relationship to gene expression underscore the potential significance of MP within and among populations. We speculate that biased correlation of methylation-polymorphic sites and genes in cotton may be a consequence of polyploidy and the attendant doubling of all genes.

A novel bidirectional expression system for simultaneous expression of both the protein-coding genes and short hairpin RNAs in mammalian cells

International Nuclear Information System (INIS)

Hung, C.-F.; Cheng, T.-L.; Wu, R.-H.; Teng, C.-F.; Chang, W.-T.

2006-01-01

RNA interference (RNAi) is an extremely powerful and widely used gene silencing approach for reverse functional genomics and molecular therapeutics. In mammals, the conserved poly(ADP-ribose) polymerase 2 (PARP-2)/RNase P bidirectional control promoter simultaneously expresses both the PARP-2 protein and RNase P RNA by RNA polymerase II- and III-dependent mechanisms, respectively. To explore this unique bidirectional control system in RNAi-mediated gene silencing strategy, we have constructed two novel bidirectional expression vectors, pbiHsH1 and pbiMmH1, which contained the PARP-2/RNase P bidirectional control promoters from human and mouse, for simultaneous expression of both the protein-coding genes and short hairpin RNAs. Analyses of the dual transcriptional activities indicated that these two bidirectional expression vectors could not only express enhanced green fluorescent protein as a functional reporter but also simultaneously transcribe shLuc for inhibiting the firefly luciferase expression. In addition, to extend its utility for the establishment of inherited stable clones, we have also reconstructed this bidirectional expression system with the blasticidin S deaminase gene, an effective dominant drug resistance selectable marker, and examined both the selection and inhibition efficiencies in drug resistance and gene expression. Moreover, we have further demonstrated that this bidirectional expression system could efficiently co-regulate the functionally important genes, such as overexpression of tumor suppressor protein p53 and inhibition of anti-apoptotic protein Bcl-2 at the same time. In summary, the bidirectional expression vectors, pbiHsH1 and pbiMmH1, should provide a simple, convenient, and efficient novel tool for manipulating the gene function in mammalian cells

Histone H3.3 promotes IgV gene diversification by enhancing formation of AID-accessible single-stranded DNA.

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Romanello, Marina; Schiavone, Davide; Frey, Alexander; Sale, Julian E

2016-07-01

Immunoglobulin diversification is driven by activation-induced deaminase (AID), which converts cytidine to uracil within the Ig variable (IgV) regions. Central to the recruitment of AID to the IgV genes are factors that regulate the generation of single-stranded DNA (ssDNA), the enzymatic substrate of AID Here, we report that chicken DT40 cells lacking variant histone H3.3 exhibit reduced IgV sequence diversification. We show that this results from impairment of the ability of AID to access the IgV genes due to reduced formation of ssDNA during IgV transcription. Loss of H3.3 also diminishes IgV R-loop formation. However, reducing IgV R-loops by RNase HI overexpression in wild-type cells does not affect IgV diversification, showing that these structures are not necessary intermediates for AID access. Importantly, the reduction in the formation of AID-accessible ssDNA in cells lacking H3.3 is independent of any effect on the level of transcription or the kinetics of RNAPII elongation, suggesting the presence of H3.3 in the nucleosomes of the IgV genes increases the chances of the IgV DNA becoming single-stranded, thereby creating an effective AID substrate. © 2016 MRC Laboratory of Molecular Biology. Published under the terms of the CC BY 4.0 license.

Genomic change, retrotransposon mobilization and extensive cytosine methylation alteration in Brassica napus introgressions from two intertribal hybridizations.

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Xueli Zhang

Full Text Available Hybridization and introgression represent important means for the transfer and/or de novo origination of traits and play an important role in facilitating speciation and plant breeding. Two sets of introgression lines in Brassica napus L. were previously established by its intertribal hybridizations with two wild species and long-term selection. In this study, the methods of amplified fragment length polymorphisms (AFLP, sequence-specific amplification polymorphism (SSAP and methylation-sensitive amplified polymorphism (MSAP were used to determine their genomic change, retrotransposon mobilization and cytosine methylation alteration in these lines. The genomic change revealed by the loss or gain of AFLP bands occurred for ∼10% of the total bands amplified in the two sets of introgressions, while no bands specific for wild species were detected. The new and absent SSAP bands appeared for 9 out of 11 retrotransposons analyzed, with low frequency of new bands and their total percentage of about 5% in both sets. MSAP analysis indicated that methylation changes were common in these lines (33.4-39.8% and the hypermethylation was more frequent than hypomethylation. Our results suggested that certain extents of genetic and epigenetic alterations were induced by hybridization and alien DNA introgression. The cryptic mechanism of these changes and potential application of these lines in breeding were also discussed.

Within-Host Variations of Human Papillomavirus Reveal APOBEC-Signature Mutagenesis in the Viral Genome.

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Hirose, Yusuke; Onuki, Mamiko; Tenjimbayashi, Yuri; Mori, Seiichiro; Ishii, Yoshiyuki; Takeuchi, Takamasa; Tasaka, Nobutaka; Satoh, Toyomi; Morisada, Tohru; Iwata, Takashi; Miyamoto, Shingo; Matsumoto, Koji; Sekizawa, Akihiko; Kukimoto, Iwao

2018-03-28

Persistent infection with oncogenic human papillomaviruses (HPVs) causes cervical cancer, accompanied with the accumulation of somatic mutations into the host genome. There are concomitant genetic changes in the HPV genome during viral infection; however, their relevance to cervical carcinogenesis is poorly understood. Here we explored within-host genetic diversity of HPV by performing deep sequencing analyses of viral whole-genome sequences in clinical specimens. The whole genomes of HPV types 16, 52 and 58 were amplified by type-specific PCR from total cellular DNA of cervical exfoliated cells collected from patients with cervical intraepithelial neoplasia (CIN) and invasive cervical cancer (ICC), and were deep-sequenced. After constructing a reference vial genome sequence for each specimen, nucleotide positions showing changes with > 0.5% frequencies compared to the reference sequence were determined for individual samples. In total, 1,052 positions of nucleotide variations were detected in HPV genomes from 151 samples (CIN1, n = 56; CIN2/3, n = 68; ICC, n = 27), with varying numbers per sample. Overall, C-to-T and C-to-A substitutions were the dominant changes observed across all histological grades. While C-to-T transitions were predominantly detected in CIN1, their prevalence was decreased in CIN2/3 and fell below that of C-to-A transversions in ICC. Analysis of the tri-nucleotides context encompassing substituted bases revealed that Tp C pN, a preferred target sequence for cellular APOBEC cytosine deaminases, was a primary site for C-to-T substitutions in the HPV genome. These results strongly imply that the APOBEC proteins are drivers of HPV genome mutation, particularly in CIN1 lesions. IMPORTANCE HPVs exhibit surprisingly high levels of genetic diversity, including a large repertoire of minor genomic variants in each viral genotype. Here, by conducting deep sequencing analyses, we show for the first time a comprehensive snapshot of the "within

Further observations on associations between the ADA gene and past malaria morbidity in Sardinia.

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Gloria-Bottini, Fulvia; Saccucci, Patrizia; Meloni, Gianfranco; Bottini, Egidio

2014-01-01

Adenosine Deaminase (ADA) contributes to the regulation of adenosine concentration and in turn to T cell activation. Genetic variability of ADA activity may have, therefore, an important role in resistance to malaria. Indeed, previous studies in Sardinia have shown a lower frequency of ADA1 *2 allele (associated with low ADA activity) in areas, where malaria was heavily endemic compared to areas where malaria was not endemic. We have now studied the ADA2 locus, another polymorphic site with two alleles ADA2 *1 and ADA2 *2 within the ADA gene. In the area of Oristano (where malaria was endemic in the past) 51 consecutive newborns and in the area of Nuoro (where malaria was not as endemic) 48 consecutive newborns were examined. ADA1 and ADA2 genotypes were determined by DNA analysis. The low frequency of the ADA1 *2 allele in the area where malaria was endemic is confirmed. The frequency of the ADA2 *2 allele is higher in Oristano than in Nuoro resulting in a higher frequency of the ADA1 *1/ADA2 *2 haplotype in Oristano as compared to Nuoro. This suggests a selective advantage of this haplotype in a malarial environment. The ADA gene shows other polymorphic sites further studies on their role in human adaptation to malaria could be rewarding. © 2014 Wiley Periodicals, Inc.

Detection of biosynthetic gene and phytohormone production by endophytic actinobacteria associated with Solanum lycopersicum and their plant-growth-promoting effect.

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Passari, Ajit Kumar; Chandra, Preeti; Zothanpuia; Mishra, Vineet Kumar; Leo, Vincent Vineeth; Gupta, Vijai Kumar; Kumar, Brijesh; Singh, Bhim Pratap

2016-10-01

In the present study, fifteen endophytic actinobacterial isolates recovered from Solanum lycopersicum were studied for their antagonistic potential and plant-growth-promoting (PGP) traits. Among them, eight isolates showed significant antagonistic and PGP traits, identified by amplification of the 16S rRNA gene. Isolate number DBT204, identified as Streptomyces sp., showed multiple PGP traits tested in planta and improved a range of growth parameters in seedlings of chili (Capsicum annuum L.) and tomato (S. lycopersicum L.). Further, genes of indole acetic acid (iaaM) and 1-aminocyclopropane-1-carboxylate (ACC) deaminase (acdS) were successively amplified from five strains. Six antibiotics (trimethoprim, fluconazole, chloramphenicol, nalidixic acid, rifampicin and streptomycin) and two phytohormones [indole acetic acid (IAA) and kinetin (KI)] were detected and quantified in Streptomyces sp. strain DBT204 using UPLC-ESI-MS/MS. The study indicates the potential of these PGP strains for production of phytohormones and shows the presence of biosynthetic genes responsible for production of secondary metabolites. It is the first report showing production of phytohormones (IAA and KI) by endophytic actinobacteria having PGP and biosynthetic potential. We propose Streptomyces sp. strain DBT204 for inoculums production and development of biofertilizers for enhancing growth of chili and tomato seedlings. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

An RNA editing/dsRNA binding-independent gene regulatory mechanism of ADARs and its clinical implication in cancer.

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Qi, Lihua; Song, Yangyang; Chan, Tim Hon Man; Yang, Henry; Lin, Chi Ho; Tay, Daryl Jin Tai; Hong, HuiQi; Tang, Sze Jing; Tan, Kar Tong; Huang, Xi Xiao; Lin, Jaymie Siqi; Ng, Vanessa Hui En; Maury, Julien Jean Pierre; Tenen, Daniel G; Chen, Leilei

2017-10-13

Adenosine-to-inosine (A-to-I) RNA editing, catalyzed by Adenosine DeAminases acting on double-stranded RNA(dsRNA) (ADAR), occurs predominantly in the 3' untranslated regions (3'UTRs) of spliced mRNA. Here we uncover an unanticipated link between ADARs (ADAR1 and ADAR2) and the expression of target genes undergoing extensive 3'UTR editing. Using METTL7A (Methyltransferase Like 7A), a novel tumor suppressor gene with multiple editing sites at its 3'UTR, we demonstrate that its expression could be repressed by ADARs beyond their RNA editing and double-stranded RNA (dsRNA) binding functions. ADARs interact with Dicer to augment the processing of pre-miR-27a to mature miR-27a. Consequently, mature miR-27a targets the METTL7A 3'UTR to repress its expression level. In sum, our study unveils that the extensive 3'UTR editing of METTL7A is merely a footprint of ADAR binding, and there are a subset of target genes that are equivalently regulated by ADAR1 and ADAR2 through their non-canonical RNA editing and dsRNA binding-independent functions, albeit maybe less common. The functional significance of ADARs is much more diverse than previously appreciated and this gene regulatory function of ADARs is most likely to be of high biological importance beyond the best-studied editing function. This non-editing side of ADARs opens another door to target cancer. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

The relationship in Japanese infants between a genetic polymorphism in the promoter region of the insulin-like growth factor I gene and the plasma level.

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Kinoshita, Yumiko; Kizaki, Zenro; Ishihara, Yasunori; Nakajima, Hisakazu; Adachi, Shinsuke; Kosaka, Kitaro; Kinugasa, Akihiko; Sugimoto, Tohru

2007-01-01

Evidence is accumulating that the promoter region of the insulin-like growth factor I (IGF-I) gene polymorphism and low levels of IGF-I are associated with type 2 diabetes, cardiovascular disease and birth weight; however, the number of wild-type alleles is different in each country. This study aimed to examine the 737/738 marker, a cytosine-adenine repeat in the promoter region of the IGF-I gene polymorphism, and plasma IGF-I levels in Japanese infants and analyze the genetic background. Data were collected for 15 months in Kyoto Prefectural University of Medicine. The body composition parameters of all infants were determined at birth. At 5 days after birth, we took blood samples to measure the product size of the promoter region of the IGF-I gene polymorphism and plasma IGF-I. In a population-based sample of 160 subjects, 6 different alleles and 16 genotypes were identified in the promoter region of the IGF-I gene polymorphism. The existence of a 196-bp allele has proved to result in a low plasma IGF-I level, a small head and chest circumference (p body composition parameters in Japanese infants. Our results suggest genetical influence on prenatal growth and serum IGF-I levels.

Transcriptional changes in epigenetic modifiers associated with gene silencing in the intestine of the sea cucumber, Apostichopus japonicus (Selenka), during aestivation

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Wang, Tianming; Yang, Hongsheng; Zhao, Huan; Chen, Muyan; Wang, Bing

2011-11-01

The sea cucumber, Apostichopus japonicus, undergoes aestivation to improve survival during periods of high-temperature. During aestivation, the metabolic rate is depressed to reduce the consumption of reserved energy. We evaluated the role of epigenetic modification on global gene silencing during metabolic rate depression in the sea cucumber. We compared the expression of epigenetic modifiers in active and aestivating sea cucumbers. The expression of three genes involved in DNA methylation and chromatin remodeling (DNA (cytosine-5)-methyltransferase 1, Methyl-CpG-binding domain protein 2), and Chromodomain-helicase-DNA-binding protein 5) was significantly higher during aestivation (Days 20 and 40). Similarly, we observed an increase in the expression of genes involved in histone acetylation (Histone deacetylase 3) and Histone-binding protein RBBP4) during the early (Days 5 and 10) and late phases (Days 20 and 40) of aestivation. There was no change in the expression of KAT2B, a histone acetyltransferase. However, the expression of histone methylation associated modifiers (Histone-arginine methyltransferase CARMER and Histone-lysine N-methyltransferase MLL5) was significantly higher after 5 d in the aestivating group. The results suggest that the expression of epigenetic modifiers involved in DNA methylation, chromatin remodeling, histone acetylation, and histone methylation is upregulated during aestivation. We hypothesize that these changes regulate global gene silencing during aestivation in A. japonicus.

Pathogenic mechanisms of intracellular bacteria.

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Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

2017-06-01

We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

A genetic screen identifies interferon-α effector genes required to suppress hepatitis C virus replication.

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Fusco, Dahlene N; Brisac, Cynthia; John, Sinu P; Huang, Yi-Wen; Chin, Christopher R; Xie, Tiao; Zhao, Hong; Jilg, Nikolaus; Zhang, Leiliang; Chevaliez, Stephane; Wambua, Daniel; Lin, Wenyu; Peng, Lee; Chung, Raymond T; Brass, Abraham L

2013-06-01

Hepatitis C virus (HCV) infection is a leading cause of end-stage liver disease. Interferon-α (IFNα) is an important component of anti-HCV therapy; it up-regulates transcription of IFN-stimulated genes, many of which have been investigated for their antiviral effects. However, all of the genes required for the antiviral function of IFNα (IFN effector genes [IEGs]) are not known. IEGs include not only IFN-stimulated genes, but other nontranscriptionally induced genes that are required for the antiviral effect of IFNα. In contrast to candidate approaches based on analyses of messenger RNA (mRNA) expression, identification of IEGs requires a broad functional approach. We performed an unbiased genome-wide small interfering RNA screen to identify IEGs that inhibit HCV. Huh7.5.1 hepatoma cells were transfected with small interfering RNAs incubated with IFNα and then infected with JFH1 HCV. Cells were stained using HCV core antibody, imaged, and analyzed to determine the percent infection. Candidate IEGs detected in the screen were validated and analyzed further. The screen identified 120 previously unreported IEGs. From these, we more fully evaluated the following: asparagine-linked glycosylation 10 homolog (yeast, α-1,2-glucosyltransferase); butyrylcholinesterase; dipeptidyl-peptidase 4 (CD26, adenosine deaminase complexing protein 2); glucokinase (hexokinase 4) regulator; guanylate cyclase 1, soluble, β 3; MYST histone acetyltransferase 1; protein phosphatase 3 (formerly 2B), catalytic subunit, β isoform; peroxisomal proliferator-activated receptor-γ-DBD-interacting protein 1; and solute carrier family 27 (fatty acid transporter), member 2; and demonstrated that they enabled IFNα-mediated suppression of HCV at multiple steps of its life cycle. Expression of these genes had more potent effects against flaviviridae because a subset was required for IFNα to suppress dengue virus but not influenza A virus. In addition, many of the host genes detected in this

Candidate genes that may be responsible for the unusual resistances exhibited by Bacillus pumilus SAFR-032 spores.

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Madhan R Tirumalai

Full Text Available The spores of several Bacillus species, including Bacillus pumilus SAFR-032 and B. safensis FO-36b, which were isolated from the spacecraft assembly facility at NASA's Jet Propulsion Laboratory, are unusually resistant to UV radiation and hydrogen peroxide. In order to identify candidate genes that might be associated with these resistances, the whole genome of B. pumilus SAFR-032, and the draft genome of B. safensis FO-36b were compared in detail with the very closely related type strain B. pumilus ATCC7061(T. 170 genes are considered characteristic of SAFR-032, because they are absent from both FO-36b and ATCC7061(T. Forty of these SAFR-032 characteristic genes are entirely unique open reading frames. In addition, four genes are unique to the genomes of the resistant SAFR-032 and FO-36b. Fifty three genes involved in spore coat formation, regulation and germination, DNA repair, and peroxide resistance, are missing from all three genomes. The vast majority of these are cleanly deleted from their usual genomic context without any obvious replacement. Several DNA repair and peroxide resistance genes earlier reported to be unique to SAFR-032 are in fact shared with ATCC7061(T and no longer considered to be promising candidates for association with the elevated resistances. Instead, several SAFR-032 characteristic genes were identified, which along with one or more of the unique SAFR-032 genes may be responsible for the elevated resistances. These new candidates include five genes associated with DNA repair, namely, BPUM_0608 a helicase, BPUM_0652 an ATP binding protein, BPUM_0653 an endonuclease, BPUM_0656 a DNA cytosine-5- methyltransferase, and BPUM_3674 a DNA helicase. Three of these candidate genes are in immediate proximity of two conserved hypothetical proteins, BPUM_0654 and BPUM_0655 that are also absent from both FO-36b and ATCC7061(T. This cluster of five genes is considered to be an especially promising target for future experimental

Investigation on the diagnosis significance of C reactive protein and adenosine deaminase in cerebrospinal fluid among children with meningitis%脑脊液C反应蛋白和腺苷脱氨酶检测在小儿脑膜炎中的诊断价值探讨

Institute of Scientific and Technical Information of China (English)

徐仁荣; 张慧华; 朱华丽

2015-01-01

Objective To determine C reactive protein and adenosine deaminase in cerebrospinal fluid,and to investigate the clinical diagnosis significance for tuberculosis meningitis,purulent meningitis and viral meningitis. Methods A total of 31 5 children with meningitis (1 02 cases of tuberculosis meningitis,1 08 cases of purulent meningitis and 1 05 cases of viral meningitis)were enrolled,96 children undergoing operation without meningitis were enrolled as control group,and their cerebrospinal fluid samples were collected.The levels of C reactive protein and adenosine deaminase were determined,and the results were compared.Results C reactive protein and adenosine deaminase in control and viral meningitis groups were significantly lower than those in tuberculosis and purulent meningitis groups (P 0.05 ).C reactive protein in purulent meningitis group was higher than that in tuberculosis meningitis group(P <0.05 ),and adenosine deaminase was lower than that in tuberculosis meningitis group (P <0.05).C reactive protein in purulent meningitis group was positive,and the positive rate was 1 00%.There were 63 positive cases in tuberculosis meningitis group,and the positive rate was 61 .76%.That in viral meningtis was negative.Conclusions In cerebrospinal fluid,C reactive protein and adenosine deaminase determinations have important reference significance for the differential diagnosis of bacterial meningitis (purulent meningitis and tuberculosis meningitis)and viral meningitis.Adenosine deaminase may be a good indicator for the diagnosis of tuberculosis meningitis,in order to provide the reference for the early diagnosis of various types of meningitis.%目的：探讨小儿脑脊液C反应蛋白和腺苷脱氨酶在结核性脑膜炎、化脓性脑膜炎和病毒性脑膜炎早期诊断中的临床意义。方法分别检测315例小儿脑膜炎患儿（包括结核性脑膜炎102例、化脓性脑膜炎108例、病毒性脑膜炎105例）及96�

The Human SLC25A33 and SLC25A36 Genes of Solute Carrier Family 25 Encode Two Mitochondrial Pyrimidine Nucleotide Transporters*

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Di Noia, Maria Antonietta; Todisco, Simona; Cirigliano, Angela; Rinaldi, Teresa; Agrimi, Gennaro; Iacobazzi, Vito; Palmieri, Ferdinando

2014-01-01

The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown. PMID:25320081

Kennedy's disease and partial androgen insensitivity syndrome. Report of 4 cases and literature review.

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Valera Yepes, Rocío; Virgili Casas, Maria; Povedano Panades, Monica; Guerrero Gual, Mireia; Villabona Artero, Carles

2015-05-01

Kennedy's disease, also known as bulbospinal muscular atrophy, is a rare, X-linked recessive neurodegenerative disorder affecting adult males. It is caused by expansion of an unstable cytosine-adenine-guanine tandem-repeat in exon 1 of the androgen-receptor gene on chromosome Xq11-12, and is characterized by spinal motor neuron progressive degeneration. Endocrinologically, these patients often have the features of hypogonadism associated to the androgen insensitivity syndrome, particularly its partial forms. We report 4 cases with the typical neurological presentation, consisting of slowly progressing generalized muscle weakness with atrophy and bulbar muscle involvement; these patients also had several endocrine manifestations; the most common non-neurological manifestation was gynecomastia. In all cases reported, molecular analysis showed an abnormal cytosine-adenine-guanine triplet repeat expansion in the androgen receptor gene. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

Molecular Evidence of Adenosine Deaminase Linking Adenosine A2A Receptor and CD26 Proteins.

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Moreno, Estefanía; Canet, Júlia; Gracia, Eduard; Lluís, Carme; Mallol, Josefa; Canela, Enric I; Cortés, Antoni; Casadó, Vicent

2018-01-01

Adenosine is an endogenous purine nucleoside that acts in all living systems as a homeostatic network regulator through many pathways, which are adenosine receptor (AR)-dependent and -independent. From a metabolic point of view, adenosine deaminase (ADA) is an essential protein in the regulation of the total intracellular and extracellular adenosine in a tissue. In addition to its cytosolic localization, ADA is also expressed as an ecto-enzyme on the surface of different cells. Dipeptidyl peptidase IV (CD26) and some ARs act as binding proteins for extracellular ADA in humans. Since CD26 and ARs interact with ADA at opposite sites, we have investigated if ADA can function as a cell-to-cell communication molecule by bridging the anchoring molecules CD26 and A 2A R present on the surfaces of the interacting cells. By combining site-directed mutagenesis of ADA amino acids involved in binding to A 2A R and a modification of the bioluminescence resonance energy transfer (BRET) technique that allows detection of interactions between two proteins expressed in different cell populations with low steric hindrance (NanoBRET), we show direct evidence of the specific formation of trimeric complexes CD26-ADA-A 2A R involving two cells. By dynamic mass redistribution assays and ligand binding experiments, we also demonstrate that A 2A R-NanoLuc fusion proteins are functional. The existence of this ternary complex is in good agreement with the hypothesis that ADA could bridge T-cells (expressing CD26) and dendritic cells (expressing A 2A R). This is a new metabolic function for ecto-ADA that, being a single chain protein, it has been considered as an example of moonlighting protein, because it performs more than one functional role (as a catalyst, a costimulator, an allosteric modulator and a cell-to-cell connector) without partitioning these functions in different subunits.

Molecular Evidence of Adenosine Deaminase Linking Adenosine A2A Receptor and CD26 Proteins

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Estefanía Moreno

2018-02-01

Full Text Available Adenosine is an endogenous purine nucleoside that acts in all living systems as a homeostatic network regulator through many pathways, which are adenosine receptor (AR-dependent and -independent. From a metabolic point of view, adenosine deaminase (ADA is an essential protein in the regulation of the total intracellular and extracellular adenosine in a tissue. In addition to its cytosolic localization, ADA is also expressed as an ecto-enzyme on the surface of different cells. Dipeptidyl peptidase IV (CD26 and some ARs act as binding proteins for extracellular ADA in humans. Since CD26 and ARs interact with ADA at opposite sites, we have investigated if ADA can function as a cell-to-cell communication molecule by bridging the anchoring molecules CD26 and A2AR present on the surfaces of the interacting cells. By combining site-directed mutagenesis of ADA amino acids involved in binding to A2AR and a modification of the bioluminescence resonance energy transfer (BRET technique that allows detection of interactions between two proteins expressed in different cell populations with low steric hindrance (NanoBRET, we show direct evidence of the specific formation of trimeric complexes CD26-ADA-A2AR involving two cells. By dynamic mass redistribution assays and ligand binding experiments, we also demonstrate that A2AR-NanoLuc fusion proteins are functional. The existence of this ternary complex is in good agreement with the hypothesis that ADA could bridge T-cells (expressing CD26 and dendritic cells (expressing A2AR. This is a new metabolic function for ecto-ADA that, being a single chain protein, it has been considered as an example of moonlighting protein, because it performs more than one functional role (as a catalyst, a costimulator, an allosteric modulator and a cell-to-cell connector without partitioning these functions in different subunits.

Methylated Host Cell Gene Promoters and Human Papillomavirus Type 16 and 18 Predicting Cervical Lesions and Cancer.

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Nina Milutin Gašperov

Full Text Available Change in the host and/or human papillomavirus (HPV DNA methylation profile is probably one of the main factors responsible for the malignant progression of cervical lesions to cancer. To investigate those changes we studied 173 cervical samples with different grades of cervical lesion, from normal to cervical cancer. The methylation status of nine cellular gene promoters, CCNA1, CDH1, C13ORF18, DAPK1, HIC1, RARβ2, hTERT1, hTERT2 and TWIST1, was investigated by Methylation Specific Polymerase Chain Reaction (MSP. The methylation of HPV18 L1-gene was also investigated by MSP, while the methylated cytosines within four regions, L1, 5'LCR, enhancer, and promoter of the HPV16 genome covering 19 CpG sites were evaluated by bisulfite sequencing. Statistically significant methylation biomarkers distinguishing between cervical precursor lesions from normal cervix were primarily C13ORF18 and secondly CCNA1, and those distinguishing cervical cancer from normal or cervical precursor lesions were CCNA1, C13ORF18, hTERT1, hTERT2 and TWIST1. In addition, the methylation analysis of individual CpG sites of the HPV16 genome in different sample groups, notably the 7455 and 7694 sites, proved to be more important than the overall methylation frequency. The majority of HPV18 positive samples contained both methylated and unmethylated L1 gene, and samples with L1-gene methylated forms alone had better prognosis when correlated with the host cell gene promoters' methylation profiles. In conclusion, both cellular and viral methylation biomarkers should be used for monitoring cervical lesion progression to prevent invasive cervical cancer.

Coordinated and sequential transcription of the cyprinid herpesvirus-3 annotated genes.

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Ilouze, Maya; Dishon, Arnon; Kotler, Moshe

2012-10-01

Cyprinid herpesvirus-3 (CyHV-3) is the cause of a fatal disease in carp and koi fish. The disease is seasonal and appears when water temperatures range from 18 to 28°C. CyHV-3 is a member of the Alloherpesviridae, a family in the Herpesvirales order that encompasses mammalian, avian and reptilian viruses. CyHV-3 is a large double-stranded DNA (dsDNA) herpesvirus with a genome of approximately 295kbp, divergent from other mammalian, avian and reptilian herpesviruses, but bearing several genes similar to cyprinid herpesvirus-1 (CyHV-1), CyHV-2, anguillid herpesvirus-1 (AngHV-1), ictalurid herpesvirus-1 (IcHV-1) and ranid herpes virus-1 (RaHV-1). Here we show that viral DNA synthesis commences 4-8h post-infection (p.i.), and is completely inhibited by pre-treatment with cytosine β-d-arabinofuranoside (Ara-C). Transcription of CyHV-3 genes initiates after infection as early as 1-2h p.i., and precedes viral DNA synthesis. All 156 annotated open reading frames (ORFs) of the CyHV-3 genome are transcribed into RNAs, most of which can be classified into immediate early (IE or α), early (E or β) and late (L or γ) classes, similar to all other herpesviruses. Several ORFs belonging to these groups are clustered along the viral genome. Copyright © 2012 Elsevier B.V. All rights reserved.

Evidence-based gene models for structural and functional annotations of the oil palm genome.

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Chan, Kuang-Lim; Tatarinova, Tatiana V; Rosli, Rozana; Amiruddin, Nadzirah; Azizi, Norazah; Halim, Mohd Amin Ab; Sanusi, Nik Shazana Nik Mohd; Jayanthi, Nagappan; Ponomarenko, Petr; Triska, Martin; Solovyev, Victor; Firdaus-Raih, Mohd; Sambanthamurthi, Ravigadevi; Murphy, Denis; Low, Eng-Ti Leslie

2017-09-08

Oil palm is an important source of edible oil. The importance of the crop, as well as its long breeding cycle (10-12 years) has led to the sequencing of its genome in 2013 to pave the way for genomics-guided breeding. Nevertheless, the first set of gene predictions, although useful, had many fragmented genes. Classification and characterization of genes associated with traits of interest, such as those for fatty acid biosynthesis and disease resistance, were also limited. Lipid-, especially fatty acid (FA)-related genes are of particular interest for the oil palm as they specify oil yields and quality. This paper presents the characterization of the oil palm genome using different gene prediction methods and comparative genomics analysis, identification of FA biosynthesis and disease resistance genes, and the development of an annotation database and bioinformatics tools. Using two independent gene-prediction pipelines, Fgenesh++ and Seqping, 26,059 oil palm genes with transcriptome and RefSeq support were identified from the oil palm genome. These coding regions of the genome have a characteristic broad distribution of GC 3 (fraction of cytosine and guanine in the third position of a codon) with over half the GC 3 -rich genes (GC 3  ≥ 0.75286) being intronless. In comparison, only one-seventh of the oil palm genes identified are intronless. Using comparative genomics analysis, characterization of conserved domains and active sites, and expression analysis, 42 key genes involved in FA biosynthesis in oil palm were identified. For three of them, namely EgFABF, EgFABH and EgFAD3, segmental duplication events were detected. Our analysis also identified 210 candidate resistance genes in six classes, grouped by their protein domain structures. We present an accurate and comprehensive annotation of the oil palm genome, focusing on analysis of important categories of genes (GC 3 -rich and intronless), as well as those associated with important functions, such as FA

Deficiency in L-serine deaminase interferes with one-carbon metabolism and cell wall synthesis in Escherichia coli K-12.

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Zhang, Xiao; El-Hajj, Ziad W; Newman, Elaine

2010-10-01

Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes L-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S L-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of L-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C(1) units and interferes with cell wall synthesis. We suggest that at high concentrations, L-serine decreases synthesis of UDP-N-acetylmuramate-L-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high L-serine is overcome in several ways: by a large concentration of L-alanine, by overproducing MurC together with a low concentration of L-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide.

Diagnostic Algorithm for Glycogenoses and Myoadenylate Deaminase Deficiency Based on Exercise Testing Parameters: A Prospective Study.

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Fabrice Rannou

Full Text Available Our aim was to evaluate the accuracy of aerobic exercise testing to diagnose metabolic myopathies.From December 2008 to September 2012, all the consecutive patients that underwent both metabolic exercise testing and a muscle biopsy were prospectively enrolled. Subjects performed an incremental and maximal exercise testing on a cycle ergometer. Lactate, pyruvate, and ammonia concentrations were determined from venous blood samples drawn at rest, during exercise (50% predicted maximal power, peak exercise, and recovery (2, 5, 10, and 15 min. Biopsies from vastus lateralis or deltoid muscles were analysed using standard techniques (reference test. Myoadenylate deaminase (MAD activity was determined using p-nitro blue tetrazolium staining in muscle cryostat sections. Glycogen storage was assessed using periodic acid-Schiff staining. The diagnostic accuracy of plasma metabolite levels to identify absent and decreased MAD activity was assessed using Receiver Operating Characteristic (ROC curve analysis.The study involved 51 patients. Omitting patients with glycogenoses (n = 3, MAD staining was absent in 5, decreased in 6, and normal in 37 subjects. Lactate/pyruvate at the 10th minute of recovery provided the greatest area under the ROC curves (AUC, 0.893 ± 0.067 to differentiate Abnormal from Normal MAD activity. The lactate/rest ratio at the 10th minute of recovery from exercise displayed the best AUC (1.0 for discriminating between Decreased and Absent MAD activities. The resulting decision tree achieved a diagnostic accuracy of 86.3%.The present algorithm provides a non-invasive test to accurately predict absent and decreased MAD activity, facilitating the selection of patients for muscle biopsy and target appropriate histochemical analysis.

Adenine N6-methylation in diverse fungi

NARCIS (Netherlands)

Seidl, Michael F.

2017-01-01

A DNA modification - methylation of cytosines and adenines - has important roles in diverse processes such as regulation of gene expression and genome stability, yet until recently adenine methylation had been considered to be only a hallmark of prokaryotes. A new study identifies abundant

Characterisation of ALS genes in the polyploid species Schoenoplectus mucronatus and implications for resistance management.

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Scarabel, Laura; Locascio, Antonella; Furini, Antonella; Sattin, Maurizio; Varotto, Serena

2010-03-01

The polyploid weed Schoenoplectus mucronatus (L.) Palla has evolved target-site resistance to ALS-inhibiting herbicides in Italian rice crops. Molecular and genetic characterisation of the resistance mechanism is relevant to the evolution and management of herbicide resistance. The authors aimed (a) to study the organisation of the target-site loci in two field-selected S. mucronatus populations with different cross-resistance patterns, (b) to identify the mutations endowing resistance to ALS inhibitors and determine the role of these mutations by using transgenesis and (c) to analyse the implications for the management of the S. mucronatus populations. Two complete ALS genes (ALS1 and ALS2) having an intron and a third partial intronless ALS gene (ALS3) were identified. The presence of multiple ALS genes was confirmed by Southern blot analyses, and ALS loci were characterised by examining cytosine methylation. In S. mucronatus leaves, the transcripts of ALS1, ALS2 and ALS3 were detected. Two mutations endowing resistance (Pro(197) to His and Trp(574) to Leu) were found in both resistant populations, but at different frequencies. Tobacco plants transformed with the two resistant alleles indicated that the Pro(197)-to-His substitution conferred resistance to SU and TP herbicides, while the allele with the Trp(574)-to-Leu substitution conferred cross-resistance to SU, TP, IMI and PTB herbicides. Schoenoplectus mucronatus has multiple ALS genes characterised by methylated sites that can influence the expression profile. The two mutated alleles proved to be responsible for ALS resistance. At population level, the resistance pattern depends on the frequency of various resistant genotypes, and this influences the efficacy of various ALS-inhibiting herbicides.

Use of MSAP markers to analyse the effects of salt stress on DNA methylation in rapeseed (Brassica napus var. oleifera.

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Gianpiero Marconi

Full Text Available Excessive soil salinity is a major ecological and agronomical problem, the adverse effects of which are becoming a serious issue in regions where saline water is used for irrigation. Plants can employ regulatory strategies, such as DNA methylation, to enable relatively rapid adaptation to new conditions. In this regard, cytosine methylation might play an integral role in the regulation of gene expression at both the transcriptional and post-transcriptional levels. Rapeseed, which is the most important oilseed crop in Europe, is classified as being tolerant of salinity, although cultivars can vary substantially in their levels of tolerance. In this study, the Methylation Sensitive Amplified Polymorphism (MSAP approach was used to assess the extent of cytosine methylation under salinity stress in salinity-tolerant (Exagone and salinity-sensitive (Toccata rapeseed cultivars. Our data show that salinity affected the level of DNA methylation. In particular methylation decreased in Exagone and increased in Toccata. Nineteen DNA fragments showing polymorphisms related to differences in methylation were sequenced. In particular, two of these were highly similar to genes involved in stress responses (Lacerata and trehalose-6-phosphatase synthase S4 and were chosen to further characterization. Bisulfite sequencing and quantitative RT-PCR analysis of selected MSAP loci showed that cytosine methylation changes under salinity as well as gene expression varied. In particular, our data show that salinity stress influences the expression of the two stress-related genes. Moreover, we quantified the level of trehalose in Exagone shoots and found that it was correlated to TPS4 expression and, therefore, to DNA methylation. In conclusion, we found that salinity could induce genome-wide changes in DNA methylation status, and that these changes, when averaged across different genotypes and developmental stages, accounted for 16.8% of the total site

Induction of cytosine arabinoside-resistant human myeloid leukemia cell death through autophagy regulation by hydroxychloroquine.

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Kim, Yundeok; Eom, Ju-In; Jeung, Hoi-Kyung; Jang, Ji Eun; Kim, Jin Seok; Cheong, June-Won; Kim, Young Sam; Min, Yoo Hong

2015-07-01

We investigated the effects of the autophagy inhibitor hydroxychloroquine (HCQ) on cell death of cytosine arabinoside (Ara-C)-resistant human acute myeloid leukemia (AML) cells. Ara-C-sensitive (U937, AML-2) and Ara-C-resistant (U937/AR, AML-2/AR) human AML cell lines were used to evaluate HCQ-regulated cytotoxicity, autophagy, and apoptosis as well as effects on cell death-related signaling pathways. We found that HCQ-induced dose- and time-dependent cell death in Ara-C-resistant cells compared to Ara-C-sensitive cell lines. The extent of cell death and features of HCQ-induced autophagic markers including increase in microtubule-associated protein light chain 3 (LC3) I conversion to LC3-II, beclin-1, ATG5, as well as green fluorescent protein-LC3 positive puncta and autophagosome were remarkably greater in U937/AR cells. Also, p62/SQSTM1 was increased in response to HCQ. p62/SQSTM1 protein interacts with both LC3-II and ubiquitin protein and is degraded in autophagosomes. Therefore, a reduction of p62/SQSTM1 indicates increased autophagic degradation, whereas an increase of p62/SQSTM1 by HCQ indicates inhibited autophagic degradation. Knock down of p62/SQSTM1 using siRNA were prevented the HCQ-induced LC3-II protein level as well as significantly reduced the HCQ-induced cell death in U937/AR cells. Also, apoptotic cell death and caspase activation in U937/AR cells were increased by HCQ, provided evidence that HCQ-induced autophagy blockade. Taken together, our data show that HCQ-induced apoptotic cell death in Ara-C-resistant AML cells through autophagy regulation. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Transcripts of the NADH-dehydrogenase subunit 3 gene are differentially edited in Oenothera mitochondria.

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Schuster, W; Wissinger, B; Unseld, M; Brennicke, A

1990-01-01

A number of cytosines are altered to be recognized as uridines in transcripts of the nad3 locus in mitochondria of the higher plant Oenothera. Such nucleotide modifications can be found at 16 different sites within the nad3 coding region. Most of these alterations in the mRNA sequence change codon identities to specify amino acids better conserved in evolution. Individual cDNA clones differ in their degree of editing at five nucleotide positions, three of which are silent, while two lead to codon alterations specifying different amino acids. None of the cDNA clones analysed is maximally edited at all possible sites, suggesting slow processing or lowered stringency of editing at these nucleotides. Differentially edited transcripts could be editing intermediates or could code for differing polypeptides. Two edited nucleotides in an open reading frame located upstream of nad3 change two amino acids in the deduced polypeptide. Part of the well-conserved ribosomal protein gene rps12 also encoded downstream of nad3 in other plants, is lost in Oenothera mitochondria by recombination events. The functional rps12 protein must be imported from the cytoplasm since the deleted sequences of this gene are not found in the Oenothera mitochondrial genome. The pseudogene sequence is not edited at any nucleotide position. Images Fig. 3. Fig. 4. Fig. 7. PMID:1688531

The role of DNA methylation in catechol-enhanced erythroid differentiation of K562 cells

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Li, Xiao-Fei; Wu, Xiao-Rong; Xue, Ming; Wang, Yan; Wang, Jie; Li, Yang; Suriguga,; Zhang, Guang-Yao; Yi, Zong-Chun

2012-01-01

Catechol is one of phenolic metabolites of benzene in vivo. Catechol is also widely used in pharmaceutical and chemical industries. In addition, fruits, vegetables and cigarette smoke also contain catechol. Our precious study showed that several benzene metabolites (phenol, hydroquinone, and 1,2,4-benzenetriol) inhibited erythroid differentiation of K562 cells. In present study, the effect of catechol on erythroid differentiation of K562 cells was investigated. Moreover, to address the role of DNA methylation in catechol-induced effect on erythroid differentiation in K562 cells, methylation levels of erythroid-specific genes were analyzed by Quantitative MassARRAY methylation analysis platform. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation in K562 cells in concentration- and time-dependent manners. The mRNA expression of erythroid specific genes, including α-globin, β-globin, γ-globin, erythroid 5-aminolevulinate synthase, erythroid porphobilinogen deaminase, and transcription factor GATA-1 genes, showed a significant concentration-dependent increase in catechol-treated K562 cells. The exposure to catechol caused a decrease in DNA methylation levels at a few CpG sites in some erythroid specific genes including α-globin, β-globin and erythroid porphobilinogen deaminase genes. These results indicated that catechol improved erythroid differentiation potency of K562 cells at least partly via up-regulating transcription of some erythroid related genes, and suggested that inhibition of DNA methylation might be involved in up-regulated expression of some erythroid related genes. -- Highlights: ► Catechol enhanced hemin-induced hemoglobin accumulation. ► Exposure to catechol resulted in up-regulated expression of erythroid genes. ► Catechol reduced methylation levels at some CpG sites in erythroid genes.

The role of DNA methylation in catechol-enhanced erythroid differentiation of K562 cells

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Li, Xiao-Fei; Wu, Xiao-Rong; Xue, Ming; Wang, Yan; Wang, Jie; Li, Yang; Suriguga,; Zhang, Guang-Yao; Yi, Zong-Chun, E-mail: yizc@buaa.edu.cn

2012-11-15

Catechol is one of phenolic metabolites of benzene in vivo. Catechol is also widely used in pharmaceutical and chemical industries. In addition, fruits, vegetables and cigarette smoke also contain catechol. Our precious study showed that several benzene metabolites (phenol, hydroquinone, and 1,2,4-benzenetriol) inhibited erythroid differentiation of K562 cells. In present study, the effect of catechol on erythroid differentiation of K562 cells was investigated. Moreover, to address the role of DNA methylation in catechol-induced effect on erythroid differentiation in K562 cells, methylation levels of erythroid-specific genes were analyzed by Quantitative MassARRAY methylation analysis platform. Benzidine staining showed that exposure to catechol enhanced hemin-induced hemoglobin accumulation in K562 cells in concentration- and time-dependent manners. The mRNA expression of erythroid specific genes, including α-globin, β-globin, γ-globin, erythroid 5-aminolevulinate synthase, erythroid porphobilinogen deaminase, and transcription factor GATA-1 genes, showed a significant concentration-dependent increase in catechol-treated K562 cells. The exposure to catechol caused a decrease in DNA methylation levels at a few CpG sites in some erythroid specific genes including α-globin, β-globin and erythroid porphobilinogen deaminase genes. These results indicated that catechol improved erythroid differentiation potency of K562 cells at least partly via up-regulating transcription of some erythroid related genes, and suggested that inhibition of DNA methylation might be involved in up-regulated expression of some erythroid related genes. -- Highlights: ► Catechol enhanced hemin-induced hemoglobin accumulation. ► Exposure to catechol resulted in up-regulated expression of erythroid genes. ► Catechol reduced methylation levels at some CpG sites in erythroid genes.

GenBank blastx search result: AK058464 [KOME

Lifescience Database Archive (English)

Full Text Available AK058464 001-016-A10 U27202.1 Actinobacillus pleuropneumoniae riboflavin biosynthesis operon, riboflavin...-specific deaminase (ribG), riboflavin synthase alpha subunit (ribB), bifunctional GTP ...cyclohydrase II/3,4-dihydroxy-2-butanone-4-phosphate synthase (ribA), and riboflavin synthase beta subunit (ribH) genes, complete cds.|BCT BCT 1e-105 +2 ...

Regulation of epithelial and lymphocyte cell adhesion by adenosine deaminase-CD26 interaction.

Science.gov (United States)

Ginés, Silvia; Mariño, Marta; Mallol, Josefa; Canela, Enric I; Morimoto, Chikao; Callebaut, Christian; Hovanessian, Ara; Casadó, Vicent; Lluis, Carmen; Franco, Rafael

2002-01-01

The extra-enzymic function of cell-surface adenosine deaminase (ADA), an enzyme mainly localized in the cytosol but also found on the cell surface of monocytes, B cells and T cells, has lately been the subject of numerous studies. Cell-surface ADA is able to transduce co-stimulatory signals in T cells via its interaction with CD26, an integral membrane protein that acts as ADA-binding protein. The aim of the present study was to explore whether ADA-CD26 interaction plays a role in the adhesion of lymphocyte cells to human epithelial cells. To meet this aim, different lymphocyte cell lines (Jurkat and CEM T) expressing endogenous, or overexpressing human, CD26 protein were tested in adhesion assays to monolayers of colon adenocarcinoma human epithelial cells, Caco-2, which express high levels of cell-surface ADA. Interestingly, the adhesion of Jurkat and CEM T cells to a monolayer of Caco-2 cells was greatly dependent on CD26. An increase by 50% in the cell-to-cell adhesion was found in cells containing higher levels of CD26. Incubation with an anti-CD26 antibody raised against the ADA-binding site or with exogenous ADA resulted in a significant reduction (50-70%) of T-cell adhesion to monolayers of epithelial cells. The role of ADA-CD26 interaction in the lymphocyte-epithelial cell adhesion appears to be mediated by CD26 molecules that are not interacting with endogenous ADA (ADA-free CD26), since SKW6.4 (B cells) that express more cell-surface ADA showed lower adhesion than T cells. Adhesion stimulated by CD26 and ADA is mediated by T cell lymphocyte function-associated antigen. A role for ADA-CD26 interaction in cell-to-cell adhesion was confirmed further in integrin activation assays. FACS analysis revealed a higher expression of activated integrins on T cell lines in the presence of increasing amounts of exogenous ADA. Taken together, these results suggest that the ADA-CD26 interaction on the cell surface has a role in lymphocyte-epithelial cell adhesion. PMID

New PAH gene promoter KLF1 and 3'-region C/EBPalpha motifs influence transcription in vitro.

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Klaassen, Kristel; Stankovic, Biljana; Kotur, Nikola; Djordjevic, Maja; Zukic, Branka; Nikcevic, Gordana; Ugrin, Milena; Spasovski, Vesna; Srzentic, Sanja; Pavlovic, Sonja; Stojiljkovic, Maja

2017-02-01

Phenylketonuria (PKU) is a metabolic disease caused by mutations in the phenylalanine hydroxylase (PAH) gene. Although the PAH genotype remains the main determinant of PKU phenotype severity, genotype-phenotype inconsistencies have been reported. In this study, we focused on unanalysed sequences in non-coding PAH gene regions to assess their possible influence on the PKU phenotype. We transiently transfected HepG2 cells with various chloramphenicol acetyl transferase (CAT) reporter constructs which included PAH gene non-coding regions. Selected non-coding regions were indicated by in silico prediction to contain transcription factor binding sites. Furthermore, electrophoretic mobility shift assay (EMSA) and supershift assays were performed to identify which transcriptional factors were engaged in the interaction. We found novel KLF1 motif in the PAH promoter, which decreases CAT activity by 50 % in comparison to basal transcription in vitro. The cytosine at the c.-170 promoter position creates an additional binding site for the protein complex involving KLF1 transcription factor. Moreover, we assessed for the first time the role of a multivariant variable number tandem repeat (VNTR) region located in the 3'-region of the PAH gene. We found that the VNTR3, VNTR7 and VNTR8 constructs had approximately 60 % of CAT activity. The regulation is mediated by the C/EBPalpha transcription factor, present in protein complex binding to VNTR3. Our study highlighted two novel promoter KLF1 and 3'-region C/EBPalpha motifs in the PAH gene which decrease transcription in vitro and, thus, could be considered as PAH expression modifiers. New transcription motifs in non-coding regions will contribute to better understanding of the PKU phenotype complexity and may become important for the optimisation of PKU treatment.

DNA methyltransferases and stress-related genes expression in zebrafish larvae after exposure to heat and copper during reprogramming of DNA methylation.

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Dorts, Jennifer; Falisse, Elodie; Schoofs, Emilie; Flamion, Enora; Kestemont, Patrick; Silvestre, Frédéric

2016-10-12

DNA methylation, a well-studied epigenetic mark, is important for gene regulation in adulthood and for development. Using genetic and epigenetic approaches, the present study aimed at evaluating the effects of heat stress and copper exposure during zebrafish early embryogenesis when patterns of DNA methylation are being established, a process called reprogramming. Embryos were exposed to 325 μg Cu/L from fertilization (<1 h post fertilization - hpf) to 4 hpf at either 26.5 °C or 34 °C, followed by incubation in clean water at 26.5 °C till 96 hpf. Significant increased mortality rates and delayed hatching were observed following exposure to combined high temperature and Cu. Secondly, both stressors, alone or in combination, significantly upregulated the expression of de novo DNA methyltransferase genes (dnmt3) along with no differences in global cytosine methylation level. Finally, Cu exposure significantly increased the expression of metallothionein (mt2) and heat shock protein (hsp70), the latter being also increased following exposure to high temperature. These results highlighted the sensitivity of early embryogenesis and more precisely of the reprogramming period to environmental challenges, in a realistic situation of combined stressors.

Molecular characterization of adenosine 5'-monophosphate deaminase--the key enzyme responsible for the umami taste of nori (Porphyra yezoensis Ueda, Rhodophyta).

Science.gov (United States)

Minami, Seiko; Sato, Minoru; Shiraiwa, Yoshihiro; Iwamoto, Koji

2011-12-01

The enzyme adenosine 5'-monophosphate deaminase (AMPD, EC 3.5.4.6) catalyzes the conversion of adenosine 5'-monophosphate to inosine 5'-mononucleotide (IMP). IMP is generally known as the compound responsible for the umami taste of the edible red alga Porphyra yezoensis Ueda that is known in Japan as nori. Therefore, we suspect that AMPD plays a key role in providing a favorable nori taste. In this study, we undertake the molecular characterization of nori-derived AMPD. The nori AMPD protein has a molecular mass of 55 kDa as estimated from both gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The calculated molecular mass from the amino acid sequence deduced from cDNA is 57.1 kDa. The isoelectric point is 5.71. The coding region of AMPD consists of 1,566 bp encoding 522 amino acids and possesses a transmembrane domain and two N-glycosylation sites. The sequence identity of nori AMPD in human and yeast AMPDs was found to be less than 50% and 20% in DNA and amino acid sequences, respectively. Proline in the conserved motif of [SA]-[LIVM]-[NGS]-[STA]-D-D-P was found to be converted to glutamate. These results indicate that nori AMPD is a novel type of AMPD.

Evidence that muscle cells do not express the histidine-rich glycoprotein associated with AMP deaminase but can internalise the plasma protein

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A.R.M. Sabbatini

2011-02-01

Full Text Available Histidine-rich glycoprotein (HRG is synthesized by liver and is present at relatively high concentration in the plasma of vertebrates. We have previously described the association of a HRG-like molecule to purified rabbit skeletal muscle AMP deaminase (AMPD. We also provided the first evidence for the presence of a HRG-like protein in human skeletal muscle where a positive correlation between HRG content and total determined AMPD activity has been shown. In the present paper we investigate the origin of skeletal muscle HRG. The screening of a human skeletal muscle cDNA expression library using an anti-HRG antibody failed to reveal any positive clone. The RT-PCR analysis, performed on human skeletal muscle RNA as well as on RNA from the rhabdomyosarcoma (RD cell line, failed to show any mRNA specific for the plasma HRG or for the putative muscle variant. When the RD cells were incubated with human plasma HRG, a time-dependent increase of the HRG immunoreactivity was detected both at the plasma membrane level and intracellularly. The internalisation of HRG was inhibited by the addition of heparin. The above data strongly suggest that skeletal muscle cells do not synthesize the muscle variant of HRG but instead can actively internalise it from plasma.

Analysis of IgV gene mutations in B cell chronic lymphocytic leukaemia according to antigen-driven selection identifies subgroups with different prognosis and usage of the canonical somatic hypermutation machinery.

Science.gov (United States)

Degan, Massimo; Bomben, Riccardo; Bo, Michele Dal; Zucchetto, Antonella; Nanni, Paola; Rupolo, Maurizio; Steffan, Agostino; Attadia, Vincenza; Ballerini, Pier Ferruccio; Damiani, Daniela; Pucillo, Carlo; Poeta, Giovanni Del; Colombatti, Alfonso; Gattei, Valter

2004-07-01

Cases of B-cell chronic lymphocytic leukaemia (B-CLL) with mutated (M) IgV(H) genes have a better prognosis than unmutated (UM) cases. We analysed the IgV(H) mutational status of B-CLL according to the features of a canonical somatic hypermutation (SHM) process, correlating this data with survival. In a series of 141 B-CLLs, 124 cases were examined for IgV(H) gene per cent mutations and skewing of replacement/silent mutations in the framework/complementarity-determining regions as evidence of antigen-driven selection; this identified three B-CLL subsets: significantly mutated (sM), with evidence of antigen-driven selection, not significantly mutated (nsM) and UM, without such evidence and IgV(H) gene per cent mutations above or below the 2% cut-off. sM B-CLL patients had longer survival within the good prognosis subgroup that had more than 2% mutations of IgV(H) genes. sM, nsM and UM B-CLL were also characterized for the biased usage of IgV(H) families, intraclonal IgV(H) gene diversification, preference of mutations to target-specific nucleotides or hotspots, and for the expression of enzymes involved in SHM (translesion DNA polymerase zeta and eta and activation-induced cytidine deaminase). These findings indicate the activation of a canonical SHM process in nsM and sM B-CLLs and underscore the role of the antigen in defining the specific clinical and biological features of B-CLL.

DNA methylation inhibits expression and transposition of the Neurospora Tad retrotransposon.

Science.gov (United States)

Zhou, Y; Cambareri, E B; Kinsey, J A

2001-06-01

Tad is a LINE-like retrotransposon of the filamentous fungus Neurospora crassa. We have analyzed both expression and transposition of this element using strains with a single copy of Tad located in the 5' noncoding sequences of the am (glutamate dehydrogenase) gene. Tad in this position has been shown to carry a de novo cytosine methylation signal which causes reversible methylation of both Tad and am upstream sequences. Here we find that methylation of the Tad sequences inhibits both Tad expression and transposition. This inhibition can be relieved by the use of 5-azacytidine, a drug which reduces cytosine methylation, or by placing the Tad/am sequences in a dim-2 genetic background.

Elevated Adenosine Induces Placental DNA Hypomethylation Independent of A2B Receptor Signaling in Preeclampsia.

Science.gov (United States)

Huang, Aji; Wu, Hongyu; Iriyama, Takayuki; Zhang, Yujin; Sun, Kaiqi; Song, Anren; Liu, Hong; Peng, Zhangzhe; Tang, Lili; Lee, Minjung; Huang, Yun; Ni, Xin; Kellems, Rodney E; Xia, Yang

2017-07-01

Preeclampsia is a prevalent pregnancy hypertensive disease with both maternal and fetal morbidity and mortality. Emerging evidence indicates that global placental DNA hypomethylation is observed in patients with preeclampsia and is linked to altered gene expression and disease development. However, the molecular basis underlying placental epigenetic changes in preeclampsia remains unclear. Using 2 independent experimental models of preeclampsia, adenosine deaminase-deficient mice and a pathogenic autoantibody-induced mouse model of preeclampsia, we demonstrate that elevated placental adenosine not only induces hallmark features of preeclampsia but also causes placental DNA hypomethylation. The use of genetic approaches to express an adenosine deaminase minigene specifically in placentas, or adenosine deaminase enzyme replacement therapy, restored placental adenosine to normal levels, attenuated preeclampsia features, and abolished placental DNA hypomethylation in adenosine deaminase-deficient mice. Genetic deletion of CD73 (an ectonucleotidase that converts AMP to adenosine) prevented the elevation of placental adenosine in the autoantibody-induced preeclampsia mouse model and ameliorated preeclampsia features and placental DNA hypomethylation. Immunohistochemical studies revealed that elevated placental adenosine-mediated DNA hypomethylation predominantly occurs in spongiotrophoblasts and labyrinthine trophoblasts and that this effect is independent of A2B adenosine receptor activation in both preeclampsia models. Extending our mouse findings to humans, we used cultured human trophoblasts to demonstrate that adenosine functions intracellularly and induces DNA hypomethylation without A2B adenosine receptor activation. Altogether, both mouse and human studies reveal novel mechanisms underlying placental DNA hypomethylation and potential therapeutic approaches for preeclampsia. © 2017 American Heart Association, Inc.

ORF Alignment: NC_000913 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available amine-6-Phosphate ... Deaminase From E.Coli, T Conformer, At 1.9a Resolution ... pdb|1FS6|A Ch...ain A, Glucosamine-6-Phosphate Deaminase ... From E.Coli, T Conformer, At ...phate Isomerase pdb|1FRZ|B Chain B, ... Glucosamine-6-Phosphate Deaminase From E.Coli, R ... C...lution ... pdb|1FRZ|A Chain A, Glucosamine-6-Phosphate Deaminase ... From E.Coli, R Conformer....hate At 2.2 A ... Resolution pdb|1CD5|A Chain A, Glucosamine-6-Phosphate ... Deaminase From E.Coli

Mechanisms of Breast Cancer in Shift Workers: DNA Methylation in Five Core Circadian Genes in Nurses Working Night Shifts.

Science.gov (United States)

Samulin Erdem, Johanna; Skare, Øivind; Petersen-Øverleir, Marte; Notø, Heidi Ødegaard; Lie, Jenny-Anne S; Reszka, Edyta; Pepłońska, Beata; Zienolddiny, Shanbeh

2017-01-01

Shift work has been suggested to be associated with breast cancer risk, and circadian disruption in shift workers is hypothesized as one of the mechanisms of increased cancer risk. There is, however, insufficient molecular evidence supporting this hypothesis. Using the quantitative methodology of pyrosequencing, epigenetic changes in 5-methyl cytosine (5mC) in five circadian genes CLOCK , BMAL1 , CRY1, PER1 and PER2 in female nurses working night shift work (278 breast cancer cases, 280 controls) were analyzed. In breast cancer cases, a medium exposure to night work was associated with increased methylation levels of the CLOCK (p=0.050), BMAL1 (p=0.001) and CRY1 (p=0.040) genes, compared with controls. Within the cases, analysis of the effects of shift work on the methylation patterns showed that methylation of CRY1 was lower in those who had worked night shift and had a high exposure (p=0.006) compared with cases that had worked only days. For cases with a medium exposure to night work, an increase in BMAL1 (p=0.003) and PER1 (p=0.035) methylation was observed compared with day working (unexposed) cases. The methylation levels of the five core circadian genes were also analyzed in relation to the estrogen and progesterone receptors status of the tumors in the cases, and no correlations were observed. Furthermore, nineteen polymorphisms in the five circadian genes were assessed for their effects on the methylation levels of the respective genes, but no associations were found. In summary, our data suggest that epigenetic regulation of CLOCK , BMAL1, CRY1 and PER1 may contribute to breast cancer in shift workers.

Induction and maintenance of DNA methylation in plant promoter sequences by apple latent spherical virus-induced transcriptional gene silencing

Directory of Open Access Journals (Sweden)

Tatsuya eKon

2014-11-01

Full Text Available Apple latent spherical virus (ALSV is an efficient virus-induced gene silencing vector in functional genomics analyses of a broad range of plant species. Here, an Agrobacterium-mediated inoculation (agroinoculation system was developed for the ALSV vector, and virus-induced transcriptional gene silencing (VITGS is described in plants infected with the ALSV vector. The cDNAs of ALSV RNA1 and RNA2 were inserted between the CaMV 35S promoter and the NOS-T sequences in a binary vector pCAMBIA1300 to produce pCALSR1 and pCALSR2-XSB or pCALSR2-XSB/MN. When these vector constructs were agroinoculated into Nicotiana benthamiana plants with a construct expressing a viral silencing suppressor, the infection efficiency of the vectors was 100%. A recombinant ALSV vector carrying part of the 35S promoter sequence induced transcriptional gene silencing of the green fluorescent protein gene in a line of N. benthamiana plants, resulting in the disappearance of green fluorescence of infected plants. Bisulfite sequencing showed that cytosine residues at CG and CHG sites of the 35S promoter sequence were highly methylated in the silenced generation 0 plants infected with the ALSV carrying the promoter sequence as well as in progeny. The ALSV-mediated VITGS state was inherited by progeny for multiple generations. In addition, induction of VITGS of an endogenous gene (chalcone synthase-A was demonstrated in petunia plants infected with an ALSV vector carrying the native promoter sequence. These results suggest that ALSV-based vectors can be applied to study DNA methylation in plant genomes, and provide a useful tool for plant breeding via epigenetic modification.

The human SLC25A33 and SLC25A36 genes of solute carrier family 25 encode two mitochondrial pyrimidine nucleotide transporters.

Science.gov (United States)

Di Noia, Maria Antonietta; Todisco, Simona; Cirigliano, Angela; Rinaldi, Teresa; Agrimi, Gennaro; Iacobazzi, Vito; Palmieri, Ferdinando

2014-11-28

The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Deficiency in l-Serine Deaminase Interferes with One-Carbon Metabolism and Cell Wall Synthesis in Escherichia coli K-12▿

Science.gov (United States)

Zhang, Xiao; El-Hajj, Ziad W.; Newman, Elaine

2010-01-01

Escherichia coli K-12 provided with glucose and a mixture of amino acids depletes l-serine more quickly than any other amino acid even in the presence of ammonium sulfate. A mutant without three 4Fe4S l-serine deaminases (SdaA, SdaB, and TdcG) of E. coli K-12 is unable to do this. The high level of l-serine that accumulates when such a mutant is exposed to amino acid mixtures starves the cells for C1 units and interferes with cell wall synthesis. We suggest that at high concentrations, l-serine decreases synthesis of UDP-N-acetylmuramate-l-alanine by the murC-encoded ligase, weakening the cell wall and producing misshapen cells and lysis. The inhibition by high l-serine is overcome in several ways: by a large concentration of l-alanine, by overproducing MurC together with a low concentration of l-alanine, and by overproducing FtsW, thus promoting septal assembly and also by overexpression of the glycine cleavage operon. S-Adenosylmethionine reduces lysis and allows an extensive increase in biomass without improving cell division. This suggests that E. coli has a metabolic trigger for cell division. Without that reaction, if no other inhibition occurs, other metabolic functions can continue and cells can elongate and replicate their DNA, reaching at least 180 times their usual length, but cannot divide. PMID:20729359

Serum Adenosine Deaminase (ADA) Activity: A Novel Screening Test to Differentiate HIV Monoinfection From HIV-HBV and HIV-HCV Coinfections.

Science.gov (United States)

Abdi, Mohammad; Rahbari, Rizgar; Khatooni, Zahed; Naseri, Nima; Najafi, Adel; Khodadadi, Iraj

2016-05-01

CD4(+) cell count, the common HIV infection screening test, is costly and unable to differentiate HIV monoinfection from its concurrent infection with hepatitis B or C virus. We aimed to ascertain diagnostic value of serum adenosine deaminase (ADA) activity as a useful tool to differentiate HIV mono- and co-infection. Blood samples were collected from 30 HIV-HBV and 30 HIV-HCV coinfected patients, 33 HIV positive subjects, and 72 controls. CD4(+) cell count, serum total ADA (tADA), and ADA1, and ADA2 isoenzyme activities were determined and their sensitivity and specificity were computed. tADA and ADA2 activities were significantly higher and CD4(+) counts were markedly lower in all patients compared with controls. Strong inverse agreements between CD4(+) cell counts and both tADA and ADA2 activities were observed. Serum tADA and ADA1 activities showed the highest specificity and the highest sensitivity, respectively, for differentiating HIV monoinfection from HIV-HBV and HIV-HCV coinfections. We showed strong agreement and correlation between CD4(+) cell count and ADA enzyme activity. Based on high ADA sensitivity and specificity, it is concluded that determination of ADA activity might be a novel diagnostic tool to distinguish of HIV monoinfection from its coinfection with HBV or HCV. © 2015 Wiley Periodicals, Inc.

MECP2 Is a Frequently Amplified Oncogene with a Novel Epigenetic Mechanism That Mimics the Role of Activated RAS in Malignancy

DEFF Research Database (Denmark)

Neupane, Manish; Clark, Allison P.; Landini, Serena

2016-01-01

An unbiased genome-scale screen for unmutated genes that drive cancer growth when overexpressed identified methyl cytosine-guanine dinucleotide (CpG) binding protein 2 (MECP2) as a novel oncogene. MECP2 resides in a region of the X-chromosome that is significantly amplified across 18% of cancers,...

Epigenetic silencing of the DNA mismatch repair gene, MLH1, induced by hypoxic stress in a pathway dependent on the histone demethylase, LSD1

Science.gov (United States)

Lu, Yuhong; Wajapeyee, Narendra; Turker, Mitchell S.; Glazer, Peter M.

2014-01-01

SUMMARY Silencing of the MLH1 gene is frequently seen in sporadic cancers. We report that hypoxia causes decreased H3K4 methylation at the MLH1 promoter via the H3K4 demethylases, LSD1 and PLU-1, and promotes long-term silencing of the promoter in a pathway that requires LSD1. Knockdown of LSD1 or its co-repressor, CoREST, also prevents the re-silencing (and cytosine DNA methylation) of the endogenous MLH1 promoter in RKO colon cancer cells following transient reactivation by the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5-aza-dC). The results demonstrate that hypoxia is a critical driving force for silencing of MLH1 through chromatin modification and indicate that the LSD1/CoREST complex is essential for MLH1 silencing. PMID:25043185

Mutations of the resistance to 6-thioguanine after exposure of Chinese hamster cells at G1 phase to x-radiation and subsequent treatment with cytosine arabinoside combined with hydroxyurea

International Nuclear Information System (INIS)

Elisova, T.V.; Feoktistova, T.P.; Stavrakova, N.M.

1988-01-01

A study was made of the effect of two-hour treatment of Chinese hamster cells with cytosine arabinoside (AraC) combined with hydroxyurea (HU) at the G 1 phase of the cell cycle on lethal and mutagenic effects of X-radiation (50 to 400 cGy). The inhibitors were shown to increase a spontaneous mutation level of the resistance to 6-thioguanine: this increase augmented by 3 times as the time the treatment increased from 1-2 to 6 h. However, while shorply enhancing the inactivating effect of X-radiation (the enhancement coefficient was 2.6) Arac+HU caused an additive, or a somewhat lesser, effect as estimated by the yield of mutations. It is suggested that AraC combined with hydroxyurea fail to modify the radiation-induced premutation damages

Can pleural adenosine deaminase (ADA) levels in pleural tuberculosis predict the presence of pulmonary tuberculosis? A CT analysis

International Nuclear Information System (INIS)

Koh, Myung Je; Lee, In Jae; Kim, Joo-Hee

2016-01-01

Aim: To assess the relationship between imaging features of pulmonary tuberculosis at computed tomography (CT) and adenosine deaminase (ADA) values via pleural fluid analysis in patients with pleural tuberculosis. Materials and methods: This retrospective study enrolled 60 patients who underwent fluid analysis for ADA and chest CT and were diagnosed with tuberculosis by culture or polymerase chain reaction of pleural fluid and sputum. The presence of centrilobular nodules, consolidation, cavitation, and mediastinal lymphadenopathy at CT were evaluated. The relationship between ADA values and the pattern of pulmonary involvement of tuberculosis was analysed. Results: Pulmonary involvement was seen in 42 of the 60 patients. A centrilobular nodular pattern was seen in 37 and consolidation in 22. In 17 patients, both findings were identified. A centrilobular nodular pattern was more common than consolidation or cavitary lesions. When ADA values were high, pulmonary involvement was more frequent (p=0.002). Comparing low and high ADA groups using an obtained cut-off value of 80 IU/l, the high group had more frequent pulmonary involvement (p<0.001). Conclusion: Patients with tuberculous pleurisy who had high ADA values had a higher probability of manifesting pulmonary tuberculosis. High ADA values may help predict contagious pleuroparenchymal tuberculosis. The most common pulmonary involvement of tuberculous pleurisy showed a centrilobular nodular pattern. - Highlights: • To know the relationship of ADA values and pulmonary involvement pattern of pleural tuberculosis. • To help exact diagnosis of pleuroparenchymal tuberculosis in clinical setting. • The imaging findings of pleuroparenchymal tuberculosis.

The Role of DNA Methylation in Xylogenesis in Different Tissues of Poplar

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Qingshi Wang

2016-07-01

Full Text Available In trees, xylem tissues play a key role in the formation of woody tissues, which have important uses for pulp and timber production; also DNA methylation plays an important part in gene regulation during xylogenesis in trees. In our study, methylation-sensitive amplified polymorphism (MSAP analysis was used to analyze the role cytosine methylation plays in wood formation in the commercially important tree species Populus tomentosa. This analysis compared the methylation patterns between xylem tissues (developing xylem and mature xylem and non-xylem tissues (cambium, shoot apex, young leaf, mature leaf, phloem, root, male catkin, and female catkin and found 10,316 polymorphic methylation sites. MSAP identified 132 candidate genes with the same methylation patterns in xylem tissues, including seven wood-related genes. The expression of these genes differed significantly between xylem and non-xylem tissue types (P<0.01. This indicated that the difference of expression of specific genes with unique methylation patterns, rather than relative methylation levels between the two tissue types plays a critical role in wood biosynthesis. However, 46.2% of candidate genes with the same methylation pattern in vascular tissues (cambium, phloem, and developing xylem did not have distinct expression patterns in xylem and non-xylem tissue. Also, bisulfite sequencing and transcriptome sequencing of MYB, NAC and FASCICLIN-LIKE AGP 13 revealed that the location of cytosine methylation in the gene might affect the expression of different transcripts from the corresponding gene. The expression of different transcripts that produce distinct proteins from a single gene might play an important role in the regulation of xylogenesis.

DNA Methylation: A Frontier in Tooth Organogenesis and Developmental Dental Defects.

Science.gov (United States)

Wan, Mian; Li, Hongyu; Zhou, Yachuan; Du, Wei; Xu, Xin; Ye, Ling; Zhou, Xuedong; Zheng, Liwei

2018-01-01

Tooth development relies on interactions between epithelial and mesenchymal tissues, which are controlled by sophisticated networks of conserved signaling. The signaling networks regulating odontogenesis have been well characterized, but the epigenetic mechanisms underlying remain to be elucidated. In this review, we describe current researches regarding the control of various genes expression by DNA methylation during odontogenesis, summarize genomic mapping of DNA methylation in various stages of tooth formation and diverse dental tissues by high-throughput approaches, and highlight the roles of DNA methylation in odontogenesis. Researches on mammals have revealed that the genomic methylation, which occurs on cytosine residues, regulates certain genes transcription. Consequently, DNA methylation plays a crucial role in spatiotemporal organization of signaling pathways, and is essential for organogenesis. Recently, mounting evidence proves that methylation of genomes contributes to the spatiotemporal gene dynamics during odontogenesis. With emerging new technologies of mapping cytosine modifications in global genome, investigators are seeking an overall view of DNA methylome dynamics that characterize genetic information to manifest across incredibly varied tooth development stages, dental tissues, and developmental dental defects. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Solvent effect on the intermolecular proton transfer of the Watson and Crick guanine-cytosine and adenine-thymine base pairs: a polarizable continuum model study.

Science.gov (United States)

Romero, Eduardo E; Hernandez, Florencio E

2018-01-03

Herein we present our results on the study of the double proton transfer (DPT) mechanism in the adenine-thymine (AT) and guanine-cytosine (GC) base pairs, both in gas phase and in solution. The latter was modeled using the polarizable continuum method (PCM) in different solvents. According to our DFT calculations, the DPT may occur for both complexes in a stepwise mechanism in condensate phase. In gas phase only the GC base pair exhibits a concerted DPT mechanism. Using the Wigner's tunneling corrections to the transition state theory we demonstrate that such corrections are important for the prediction of the rate constants of both systems in gas and in condensate phase. We also show that (i) as the polarity of the medium decreases the equilibrium constant of the DPT reaction increases in both complexes, and (ii) that the equilibrium constant in the GC complex is four orders of magnitude larger than in AT. This observation suggests that the spontaneous mutations in DNA base pairs are more probable in GC than in AT.

Epigenetic silencing of nucleolar rRNA genes in Alzheimer's disease.

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Maciej Pietrzak

Full Text Available Ribosomal deficits are documented in mild cognitive impairment (MCI, which often represents an early stage Alzheimer's disease (AD, as well as in advanced AD. The nucleolar rRNA genes (rDNA, transcription of which is critical for ribosomal biogenesis, are regulated by epigenetic silencing including promoter CpG methylation.To assess whether CpG methylation of the rDNA promoter was dysregulated across the AD spectrum, we analyzed brain samples from 10 MCI-, 23 AD-, and, 24 age-matched control individuals using bisulfite mapping. The rDNA promoter became hypermethylated in cerebro-cortical samples from MCI and AD groups. In parietal cortex, the rDNA promoter was hypermethylated more in MCI than in advanced AD. The cytosine methylation of total genomic DNA was similar in AD, MCI, and control samples. Consistent with a notion that hypermethylation-mediated silencing of the nucleolar chromatin stabilizes rDNA loci, preventing their senescence-associated loss, genomic rDNA content was elevated in cerebrocortical samples from MCI and AD groups.In conclusion, rDNA hypermethylation could be a new epigenetic marker of AD. Moreover, silencing of nucleolar chromatin may occur during early stages of AD pathology and play a role in AD-related ribosomal deficits and, ultimately, dementia.

Silver(I)-Mediated Base Pairs in DNA Sequences Containing 7-Deazaguanine/Cytosine: towards DNA with Entirely Metallated Watson-Crick Base Pairs.

Science.gov (United States)

Méndez-Arriaga, José M; Maldonado, Carmen R; Dobado, José A; Galindo, Miguel A

2018-03-26

DNA sequences comprising noncanonical 7-deazaguanine ( 7C G) and canonical cytosine (C) are capable of forming Watson-Crick base pairs via hydrogen bonds as well as silver(I)-mediated base pairs by coordination to central silver(I) ions. Duplexes I and II containing 7C G and C have been synthesized and characterized. The incorporation of silver(I) ions into these duplexes has been studied by means of temperature-dependent UV spectroscopy, circular dichroism, and DFT calculations. The results suggest the formation of DNA molecules comprising contiguous metallated 7C G-Ag I -C Watson-Crick base pairs that preserve the original B-type conformation. Furthermore, additional studies performed on duplex III indicated that, in the presence of Ag I ions, 7C G-C and 7C A-T Watson-Crick base pairs ( 7C A, 7-deazadenine; T, thymine) can be converted to metallated 7C G-Ag I -C and 7C A-Ag I -T base pairs inside the same DNA molecule whilst maintaining its initial double helix conformation. These findings are very important for the development of customized silver-DNA nanostructures based on a Watson-Crick complementarity pattern. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DNA Hypermethylation of the Serotonin Receptor Type-2A Gene Is Associated with a Worse Response to a Weight Loss Intervention in Subjects with Metabolic Syndrome

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Aurora Perez-Cornago

2014-06-01

Full Text Available Understanding the regulation of gene activities depending on DNA methylation has been the subject of much recent study. However, although polymorphisms of the HTR2A gene have been associated with both obesity and psychiatric disorders, the role of HTR2A gene methylation in these illnesses remains uncertain. The aim of this study was to evaluate the association of HTR2A gene promoter methylation levels in white blood cells (WBC with obesity traits and depressive symptoms in individuals with metabolic syndrome (MetS enrolled in a behavioural weight loss programme. Analyses were based on 41 volunteers (mean age 49 ± 1 year recruited within the RESMENA study. Depressive symptoms (as determined using the Beck Depression Inventory, anthropometric and biochemical measurements were analysed at the beginning and after six months of weight loss treatment. At baseline, DNA from WBC was isolated and cytosine methylation in the HTR2A gene promoter was quantified by a microarray approach. In the whole-study sample, a positive association of HTR2A gene methylation with waist circumference and insulin levels was detected at baseline. Obesity measures significantly improved after six months of dietary treatment, where a lower mean HTR2A gene methylation at baseline was associated with major reductions in body weight, BMI and fat mass after the treatment. Moreover, mean HTR2A gene methylation at baseline significantly predicted the decrease in depressive symptoms after the weight loss treatment. In conclusion, this study provides newer evidence that hypermethylation of the HTR2A gene in WBC at baseline is significantly associated with a worse response to a weight-loss intervention and with a lower decrease in depressive symptoms after the dietary treatment in subjects with MetS.

Identification of a point mutation in growth factor repeat C of the low density lipoprotein-receptor gene in a patient with homozygous familial hypercholesterolemia

International Nuclear Information System (INIS)

Soutar, A.K.; Knight, B.L.; Patel, D.D.

1989-01-01

The coding region of the low density lipoprotein (LDL)-receptor gene from a patient (MM) with homozygous familial hypercholesterolemia (FH) has been sequenced from six overlapping 500-base-pair amplified fragments of the cDNA from cultured skin fibroblasts. Two separate single nucleotide base changes from the normal sequence were detected. The first involved substitution of guanine for adenine in the third position of the codon for amino acid residue Cys-27 and did not affect the protein sequence. The second mutation was substitution of thymine for cytosine in the DNA for the codon for amino acid residue 664, changing the codon from CCG (proline) to CTG (leucine) and introducing a new site for the restriction enzyme PstI. MM is a true homozygote with two identical genes, and the mutation cosegregated with clinically diagnosed FH in his family in which first cousin marriages occurred frequently. LDL receptors in MM's skin fibroblasts bind less LDL than normal and with reduced affinity. Thus this naturally occurring single point mutation affects both intracellular transport of the protein and ligand binding and occurs in growth factor-like repeat C, a region that has not previously been found to influence LDL binding

Radiation effects on DNA methylation in mice

International Nuclear Information System (INIS)

Komura, J.; Kurishita, A.; Miyamura, Y.; Ono, T.; Tawa, R.; Sakurai, H.

1992-01-01

Effects of ionizing radiation on DNA methylation in liver, brain and spleen were examined by high performance liquid chromatography (HPLC). The total methylated cytosine level in the genome was reduced within 8 hours after 3.8 Gy of irradiation in liver of adult mice. But no appreciable effect was observed in brain and spleen. When mice were irradiated at newborn, liver DNA revealed no change in methylated cytosine level. Even though slight effects of radiation were detected in he methylation of the c-myc and c-fos genes, they were only temporary and no long-term effects were observed. These data suggest that the effect of radiation on DNA methylation in vivo is not prevailing a DNA damage, but rather influenced much through biological parameters. (author)

Cytosine hypomethylation at CHG and CHH sites in the pleiotropic ...

Indian Academy of Sciences (India)

Ribonuclease/transcriptional repressor (R/TR). 59. MULTICOPY SUPRESSOR OF IRA1 (MSI). 60. AP2-domain DNA-binding protein (ORCA3). 61. LEAFY PETIOLE (LEP). 62. GLYCINE-RICH PROTEIN 2B (ATGRP2B). 63. LEAFY COTYLEDON 2 (LEC2). 64. YELLOW-LEAF-SPECIFIC GENE 9 (YLS9). 65. TRANSCRIPTION ...

The global repressor FliZ antagonizes gene expression by σS-containing RNA polymerase due to overlapping DNA binding specificity.

Science.gov (United States)

Pesavento, Christina; Hengge, Regine

2012-06-01

FliZ, a global regulatory protein under the control of the flagellar master regulator FlhDC, was shown to antagonize σ(S)-dependent gene expression in Escherichia coli. Thereby it plays a pivotal role in the decision between alternative life-styles, i.e. FlhDC-controlled flagellum-based motility or σ(S)-dependent curli fimbriae-mediated adhesion and biofilm formation. Here, we show that FliZ is an abundant DNA-binding protein that inhibits gene expression mediated by σ(S) by recognizing operator sequences that resemble the -10 region of σ(S)-dependent promoters. FliZ does so with a structural element that is similar to region 3.0 of σ(S). Within this element, R108 in FliZ corresponds to K173 in σ(S), which contacts a conserved cytosine at the -13 promoter position that is specific for σ(S)-dependent promoters. R108 as well as C(-13) are also crucial for DNA binding by FliZ. However, while a number of FliZ binding sites correspond to known σ(S)-dependent promoters, promoter activity is not a prerequisite for FliZ binding and repressor function. Thus, we demonstrate that FliZ also feedback-controls flagellar gene expression by binding to a site in the flhDC control region that shows similarity only to a -10 element of a σ(S)-dependent promoter, but does not function as a promoter.

Pulsed magnetic field from video display terminals enhances teratogenic effects of cytosine arabinoside in mice

Energy Technology Data Exchange (ETDEWEB)

Chiang, H.; Wu, R.Y.; Shao, B.J.; Fu, Y.D.; Yao, G.D.; Lu, D.J. [Zhejiang Medical Univ. (China)

1995-05-01

Eighty-nine Swiss Webster mice were randomly divided into four groups: a control group, a pulsed magnetic field (PMF) group, a cytosine arabinoside (ara-C, a teratogen) group, and a combined PMF + ara-C group. Mice in the PMF and PMF + ara-C groups were irradiated with a PMF (a sawtooth waveform with 52 {mu}s rise time, 12{mu}s decay time, and 15.6 kHz frequency) at a peak magnetic flux density of 40 {mu}T for 4 hours daily on days 6-17 of gestation. The mice in the ara-C and the PMF + ara-C groups were injected intraperitoneally on day 9 of gestation with 10 mg/kg of ara-C. The incidence of resorption and dead fetuses was not affected by PMF but was increased by ara-C injection. The malformation incidence of cleft palate (CP) and/or cleft lip (CL) was significantly higher in all three of the treated groups than in the control group (P < 0.05). If, however, statistical analyses had been done on litters rather than on individual fetuses, they would show that the incidence of CP and/or CL in the PMF group is not significantly greater than that in the control group. A significantly higher incidence of CP and/or CL was found in the PMF + ara-C group (49%) than the ara-C alone group (26.1%). These data suggest that PMF might enhance the development of ara-C-induced CP and/or CL. The incidence of minor variations in skeletal development, including reduction of skeletal calcification and loss of skeleton, was not statistically significant in the PMF group. However, it was higher in the two ara-C-treated groups, and there was no significant difference between the ara-C alone group and the ara-C + PMF group. From these results it is concluded that the very weak embryotoxic effects of PMF exposure may be revealed and enhanced in combination with a teratogenic agent.

The Role of CREB in CML

Science.gov (United States)

2008-02-01

responses differ after stroke, seizures, hypoglycemia , and hypoxia: Blood genomic fingerprints of disease. Ann Neurol 2001;50:699–707. 62 Whitney LW...et al. Engraft- ment of gene-modified umbilical cord blood cells in neonates with adenosine deaminase defi- ciency. Nat Med. 1995;1:1017-1023. 33...Proteolysis Targeting Chimeric molecules: Recruiting Cancer- Causing Proteins for Ubiquitination and Degradation. Modulation of Protein Stability in

Genetic transformation of sweet orange with the coat protein gene of Citrus psorosis virus and evaluation of resistance against the virus.

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Zanek, María Cecilia; Reyes, Carina Andrea; Cervera, Magdalena; Peña, Eduardo José; Velázquez, Karelia; Costa, Norma; Plata, Maria Inés; Grau, Oscar; Peña, Leandro; García, María Laura

2008-01-01

Citrus psorosis is a serious viral disease affecting citrus trees in many countries. Its causal agent is Citrus psorosis virus (CPsV), the type member of genus Ophiovirus. CPsV infects most important citrus varieties, including oranges, mandarins and grapefruits, as well as hybrids and citrus relatives used as rootstocks. Certification programs have not been sufficient to control the disease and no sources of natural resistance have been found. Pathogen-derived resistance (PDR) can provide an efficient alternative to control viral diseases in their hosts. For this purpose, we have produced 21 independent lines of sweet orange expressing the coat protein gene of CPsV and five of them were challenged with the homologous CPV 4 isolate. Two different viral loads were evaluated to challenge the transgenic plants, but so far, no resistance or tolerance has been found in any line after 1 year of observations. In contrast, after inoculation all lines showed characteristic symptoms of psorosis in the greenhouse. The transgenic lines expressed low and variable amounts of the cp gene and no correlation was found between copy number and transgene expression. One line contained three copies of the cp gene, expressed low amounts of the mRNA and no coat protein. The ORF was cytosine methylated suggesting a PTGS mechanism, although the transformant failed to protect against the viral load used. Possible causes for the failed protection against the CPsV are discussed.

Plant Growth-Promoting Rhizobacteria Enhance Salinity Stress Tolerance in Okra through ROS-Scavenging Enzymes

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Sheikh Hasna Habib

2016-01-01

Full Text Available Salinity is a major environmental stress that limits crop production worldwide. In this study, we characterized plant growth-promoting rhizobacteria (PGPR containing 1-aminocyclopropane-1-carboxylate (ACC deaminase and examined their effect on salinity stress tolerance in okra through the induction of ROS-scavenging enzyme activity. PGPR inoculated okra plants exhibited higher germination percentage, growth parameters, and chlorophyll content than control plants. Increased antioxidant enzyme activities (SOD, APX, and CAT and upregulation of ROS pathway genes (CAT, APX, GR, and DHAR were observed in PGPR inoculated okra plants under salinity stress. With some exceptions, inoculation with Enterobacter sp. UPMR18 had a significant influence on all tested parameters under salt stress, as compared to other treatments. Thus, the ACC deaminase-containing PGPR isolate Enterobacter sp. UPMR18 could be an effective bioresource for enhancing salt tolerance and growth of okra plants under salinity stress.

Twenty-Five Years of Gene Therapy for ADA-SCID: From Bubble Babies to an Approved Drug.

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Ferrua, Francesca; Aiuti, Alessandro

2017-11-01

Twenty-five years have passed since first attempts of gene therapy (GT) in children affected by severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA) defect, also known by the general public as bubble babies. ADA-SCID is fatal early in life if untreated. Unconditioned hematopoietic stem cell (HSC) transplant from matched sibling donor represents a curative treatment but is available for few patients. Enzyme replacement therapy can be life-saving, but its chronic use has many drawbacks. This review summarizes the history of ADA-SCID GT over the last 25 years, starting from first pioneering studies in the early 1990s using gamma-retroviral vectors, based on multiple infusions of genetically corrected autologous peripheral blood lymphocytes. HSC represented the ideal target for gene correction to guarantee production of engineered multi-lineage progeny, but it required a decade to achieve therapeutic benefit with this approach. Introduction of low-intensity conditioning represented a crucial step in achieving stable gene-corrected HSC engraftment and therapeutic levels of ADA-expressing cells. Recent clinical trials demonstrated that gamma-retroviral GT for ADA-SCID has a favorable safety profile and is effective in restoring normal purine metabolism and immune functions in patients >13 years after treatment. No abnormal clonal proliferation or leukemia development have been observed in >40 patients treated experimentally in five different centers worldwide. In 2016, the medicinal product Strimvelis™ received marketing approval in Europe for patients affected by ADA-SCID without a suitable human leukocyte antigen-matched related donor. Positive safety and efficacy results have been obtained in GT clinical trials using lentiviral vectors encoding ADA. The results obtained in last 25 years in ADA-SCID GT development fundamentally contributed to improve patients' prognosis, together with earlier diagnosis thanks to newborn screening. These advances

Induction of epigenetic variation in Arabidopsis by over-expression of DNA METHYLTRANSFERASE1 (MET1.

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Samuel Brocklehurst

Full Text Available Epigenetic marks such as DNA methylation and histone modification can vary among plant accessions creating epi-alleles with different levels of expression competence. Mutations in epigenetic pathway functions are powerful tools to induce epigenetic variation. As an alternative approach, we investigated the potential of over-expressing an epigenetic function, using DNA METHYLTRANSFERASE1 (MET1 for proof-of-concept. In Arabidopsis thaliana, MET1 controls maintenance of cytosine methylation at symmetrical CG positions. At some loci, which contain dense DNA methylation in CG- and non-CG context, loss of MET1 causes joint loss of all cytosines methylation marks. We find that over-expression of both catalytically active and inactive versions of MET1 stochastically generates new epi-alleles at loci encoding transposable elements, non-coding RNAs and proteins, which results for most loci in an increase in expression. Individual transformants share some common phenotypes and genes with altered gene expression. Altered expression states can be transmitted to the next generation, which does not require the continuous presence of the MET1 transgene. Long-term stability and epigenetic features differ for individual loci. Our data show that over-expression of MET1, and potentially of other genes encoding epigenetic factors, offers an alternative strategy to identify epigenetic target genes and to create novel epi-alleles.

A novel class of chemicals that react with abasic sites in DNA and specifically kill B cell cancers.

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Shanqiao Wei

Full Text Available Most B cell cancers overexpress the enzyme activation-induced deaminase at high levels and this enzyme converts cytosines in DNA to uracil. The constitutive expression of this enzyme in these cells greatly increases the uracil content of their genomes. We show here that these genomes also contain high levels of abasic sites presumably created during the repair of uracils through base-excision repair. We further show that three alkoxyamines with an alkyne functional group covalently link to abasic sites in DNA and kill immortalized cell lines created from B cell lymphomas, but not other cancers. They also do not kill normal B cells. Treatment of cancer cells with one of these chemicals causes strand breaks, and the sensitivity of the cells to this chemical depends on the ability of the cells to go through the S phase. However, other alkoxyamines that also link to abasic sites- but lack the alkyne functionality- do not kill cells from B cell lymphomas. This shows that the ability of alkoxyamines to covalently link to abasic sites is insufficient for their cytotoxicity and that the alkyne functionality may play a role in it. These chemicals violate the commonly accepted bioorthogonality of alkynes and are attractive prototypes for anti-B cell cancer agents.

Lower frequency of the low activity adenosine deaminase allelic variant (ADA1*2 in schizophrenic patients Diminuição da frequência da variante alélica de baixa atividade da adenosina desaminase (ADA1*2 em pacientes esquizofrênicos

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Gustavo Pimentel Dutra

2010-09-01

Full Text Available OBJECTIVE: Adenosine may play a role in the pathophysiology of schizophrenia, since it modulates the release of several neurotransmitters such as glutamate, dopamine, serotonin and acetylcholine, decreases neuronal activity by pos-synaptic hyperpolarization and inhibits dopaminergic activity. Adenosine deaminase participates in purine metabolism by converting adenosine into inosine. The most frequent functional polymorphism of adenosine deaminase (22G→A (ADA1*2 exhibits 20-30% lower enzymatic activity in individuals with the G/A genotype than individuals with the G/G genotype. The aim of this study was to evaluate the ADA polymorphism 22G→A (ADA1*2 in schizophrenic patients and healthy controls. METHOD: The genotypes of the ADA 22G→A were identified with allele-specific PCR strategy in 152 schizophrenic patients and 111 healthy individuals. RESULTS: A significant decrease in the frequency of the G/A genotype was seen in schizophrenic patients (7/152 - 4.6% relative to controls (13/111 - 11.7%, p = 0.032, OR = 2.6. CONCLUSION: These results suggest that the G/A genotype associated with low adenosine deaminase activity and, supposingly, with higher adenosine levels is less frequent among schizophrenic patients.OBJETIVO: A adenosina pode ter um papel importante na fisiopatologia da esquizofrenia, uma vez que modula a liberação de vários neurotransmissores, tais como glutamato, dopamina, serotonina e acetilcolina, diminui a atividade neuronal por hiperpolarização pós-sináptica e inibe a atividade dopaminérgica. A adenosina desaminase participa do metabolismo das purinas pela conversão de adenosina em inosina. O mais frequente polimorfismo funcional da adenosina desaminase (22G →A (ADA1*2 exibe uma diminuição de 20-30% da atividade funcional em indivíduos com genótipo G/A quando comparados com indivíduos com o genótipo G/G. O objetivo deste estudo foi avaliar o polimorfismo 22G→A (ADA1*2 em pacientes esquizofrênicos e em

Curcumin improves episodic memory in cadmium induced memory impairment through inhibition of acetylcholinesterase and adenosine deaminase activities in a rat model.

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Akinyemi, Ayodele Jacob; Okonkwo, Princess Kamsy; Faboya, Opeyemi Ayodeji; Onikanni, Sunday Amos; Fadaka, Adewale; Olayide, Israel; Akinyemi, Elizabeth Olufisayo; Oboh, Ganiyu

2017-02-01

Curcumin, the main polyphenolic component of turmeric (Curcuma longa) rhizomes has been reported to exert cognitive enhancing potential with limited scientific basis. Hence, this study sought to evaluate the effect of curcumin on cerebral cortex acetylcholinesterase (AChE) and adenosine deaminase (ADA) activities in cadmium (Cd)-induced memory impairment in rats. Animals were divided into six groups (n = 6): saline/vehicle, saline/curcumin 12.5 mg/kg, saline/curcumin 25 mg/kg, Cd/vehicle, Cd/curcumin 12.5 mg/kg, and Cd/curcumin 25 mg/kg. Rats received Cd (2.5 mg/kg) and curcumin (12.5 and 25 mg/kg, respectively) by gavage for 7 days. The results of this study revealed that cerebral cortex AChE and ADA activities were increased in Cd-poisoned rats, and curcumin co-treatment reversed these activities to the control levels. Furthermore, Cd intoxication increased the level of lipid peroxidation in cerebral cortex with a concomitant decreased in functional sulfuhydryl (-SH) group and nitric oxide (NO), a potent neurotransmitter and neuromodulatory agent. However, the co-treatment with curcumin at 12.5 and 25 mg/kg, respectively increased the non-enzymatic antioxidant status and NO in cerebral cortex with a decreased in malondialdehyde (MDA) level. Therefore, inhibition of AChE and ADA activities as well as increased antioxidant status by curcumin in Cd-induced memory dysfunction could suggest some possible mechanism of action for their cognitive enhancing properties.

Evaluation of a diagnostic flow chart applying medical thoracoscopy, adenosine deaminase and T-SPOT.TB in diagnosis of tuberculous pleural effusion.

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He, Y; Zhang, W; Huang, T; Wang, X; Wang, M

2015-10-01

To evaluate a diagnostic flow chart applying medical thoracoscoy (MT), adenosine deaminase (ADA) and T-SPOT.TB in diagnosis of tuberculous pleural effusion (TPE) at a high TB burden country. 136 patients with pleural effusion (PE) were enrolled and divided into TPE and Non-TPE group. MT (histology), PE ADA and T-SPOT.TB were conducted on all patients. ROC analysis was performed for the best cut-off value of PE ADA in detection of TPE. The diagnostic flow chart applying MT, ADA and T-SPOT.TB was evaluated for improving the limitations of each diagnostic method. ROC analysis showed that the best cut-off value of PE ADA was 30U/L. The sensitivity and specificity of these tests were calculated respectively to be: 71.4% (58.5%-81.6%) and 100% (95.4-100.0%) for MT, 92.9% (83.0-97.2%) and 68.8% (57.9-77.9%) for T-SPOT.TB, and 80.0% (69.6-88.1%) and 92.9% (82.7-98.0%) for PE ADA. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value and negative predictive value of the diagnostic flow chart were 96.4% (87.9-99.0%), 96.3% (89.6-98.7%), 25.714, 0.037, 97.4 and 94.9, respectively. The diagnostic flow chart applying MT, ADA and T-SPOT.TB is an accurate and rapid diagnostic method in detection of TPE.

Characterization of Mn-resistant endophytic bacteria from Mn-hyperaccumulator Phytolacca americana and their impact on Mn accumulation of hybrid penisetum.

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Zhang, Wen-Hui; Chen, Wei; He, Lin-Yan; Wang, Qi; Sheng, Xia-Fang

2015-10-01

Three hundred Mn-resistant endophytic bacteria were isolated from the Mn-hyperaccumulator, Phytolacca americana, grown at different levels of Mn (0, 1, and 10mM) stress. Under no Mn stress, 90%, 92%, and 11% of the bacteria produced indole acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, respectively. Under Mn stress, 68-94%, 91-92%, and 21-81% of the bacteria produced IAA, siderophore, and ACC deaminase, respectively. Greater percentages of ACC deaminase-producing bacteria were found in the Mn-treated P. americana. Furthermore, the ratios of IAA- and siderophore-producing bacteria were significantly higher in the Mn treated plant leaves, while the ratio of ACC deaminase-producing bacteria was significantly higher in the Mn treated-roots. Based on 16S rRNA gene sequence analysis, Mn-resistant bacteria were affiliated with 10 genera. In experiments involving hybrid penisetum grown in soils treated with 0 and 1000mgkg(-1) of Mn, inoculation with strain 1Y31 was found to increase the root (ranging from 6.4% to 18.3%) and above-ground tissue (ranging from 19.3% to 70.2%) mass and total Mn uptake of above-ground tissues (64%) compared to the control. Furthermore, inoculation with strain 1Y31 was found to increase the ratio of IAA-producing bacteria in the rhizosphere and bulk soils of hybrid penisetum grown in Mn-added soils. The results showed the effect of Mn stress on the ratio of the plant growth-promoting factor-producing endophytic bacteria of P. americana and highlighted the potential of endophytic bacterium as an inoculum for enhanced phytoremediation of Mn-polluted soils by hybrid penisetum plants. Copyright © 2015 Elsevier Inc. All rights reserved.

Avaliação da adenosina desaminase no diagnóstico da tuberculose pleural: uma metanálise brasileira Evaluation of adenosine deaminase in the diagnosis of pleural tuberculosis: a Brazilian meta-analysis

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Patrizio Morisson

2008-04-01

Full Text Available OBJETIVO: Avaliar trabalhos brasileiros resumindo a acurácia da adenosina desaminase no diagnóstico da tuberculose pleural, com o intuito de contribuir para a concretização do exame como rotina na investigação dos derrames pleurais. MÉTODOS: Depois de realizada uma busca por trabalhos brasileiros referentes à dosagem da adenosina desaminase no líquido pleural, estes foram avaliados e incluídos no estudo. A análise dos dados foi feita por meio da curva summary receiver operating characteristic (SROC que possibilitou a reunião dos estudos quanto a acurácia para o diagnóstico. Com os valores globais de sensibilidade e especificidade foi aplicado o teorema de Bayes para calcular as probabilidades pós-teste em diferentes prevalências da doença. RESULTADOS: Entre 1987 e 2005 foram encontrados 25 estudos contendo informações suficientes que poderiam ser utilizadas na metanálise. Após avaliação, foram incluídos nove estudos, totalizando 1.674 pacientes. De acordo com a curva SROC, foi encontrada uma sensibilidade de 91,8% (IC95%: 89,8-93,6% e uma especificidade de 88,4% (IC95%: 86,0-90,5%, com uma área abaixo da curva de 0,969. O odds ratio global foi de 112,0 (IC95%: 51,6-243,2. Considerando uma prevalência da tuberculose pleural de 50% (considerada neutra, a probabilidade do diagnóstico pós-teste positivo é de 88,7% e sua exclusão após resultado negativo de 91,5%. CONCLUSÕES: Apesar das diferenças encontradas entre os estudos, é possível concluir que a adenosina desaminase possui alta acurácia no diagnóstico da tuberculose pleural, devendo ser utilizada de rotina em sua investigação.OBJECTIVE: To evaluate Brazilian studies by summarizing the accuracy of adenosine deaminase in the diagnosis of pleural tuberculosis, with the objective of lending support to the movement to make the test part of the routine investigation of pleural effusions. METHODS: A search for Brazilian studies related to the determination of

Comparison of identical and functional Igh alleles reveals a nonessential role for Eμ in somatic hypermutation and class-switch recombination.

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Li, Fubin; Yan, Yi; Pieretti, Joyce; Feldman, Danielle A; Eckhardt, Laurel A

2010-11-15

Somatic hypermutation (SHM), coupled with Ag selection, provides a mechanism for generating Abs with high affinity for invading pathogens. Class-switch recombination (CSR) ensures that these Abs attain pathogen-appropriate effector functions. Although the enzyme critical to both processes, activation-induced cytidine deaminase, has been identified, it remains unclear which cis-elements within the Ig loci are responsible for recruiting activation-induced cytidine deaminase and promoting its activity. Studies showed that Ig gene-transcription levels are positively correlated with the frequency of SHM and CSR, making the intronic, transcriptional enhancer Eμ a likely contributor to both processes. Tests of this hypothesis yielded mixed results arising, in part, from the difficulty in studying B cell function in mice devoid of Eμ. In Eμ's absence, V(H) gene assembly is dramatically impaired, arresting B cell development. The current study circumvented this problem by modifying the murine Igh locus through simultaneous insertion of a fully assembled V(H) gene and deletion of Eμ. The behavior of this allele was compared with that of a matched allele carrying the same V(H) gene but with Eμ intact. Although IgH transcription was as great or greater on the Eμ-deficient allele, CSR and SHM were consistently, but modestly, reduced relative to the allele in which Eμ remained intact. We conclude that Eμ contributes to, but is not essential for, these complex processes and that its contribution is not as a transcriptional enhancer but, rather, is at the level of recruitment and/or activation of the SHM/CSR machinery.

Altering the spectrum of immunoglobulin V gene somatic hypermutation by modifying the active site of AID

OpenAIRE

Wang, Meng; Rada, Cristina; Neuberger, Michael S.

2010-01-01

High-affinity antibodies are generated by somatic hypermutation with nucleotide substitutions introduced into the IgV in a semirandom fashion, but with intrinsic mutational hotspots strategically located to optimize antibody affinity maturation. The process is dependent on activation-induced deaminase (AID), an enzyme that can deaminate deoxycytidine in DNA in vitro, where its activity is sensitive to the identity of the 5?-flanking nucleotide. As a critical test of whether such DNA deaminati...

Characterization of plant-growth promoting diazotrophic bacteria isolated from field grown Chinese cabbage under different fertilization conditions.

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Yim, Woo-Jong; Poonguzhali, Selvaraj; Madhaiyan, Munusamy; Palaniappan, Pitchai; Siddikee, M A; Sa, Tongmin

2009-04-01

Diazotrophic bacteria isolated from the rhizosphere of Chinese cabbage were assessed for other plant growth promoting characteristics viz., production of IAA, ethylene, ACC deaminase, phosphate solubilization, and gnotobiotic root elongation. Their effect on inoculation to Chinese cabbage was also observed under growth chamber conditions. A total of 19 strains that showed higher nitrogenase activity identified by 16S rRNA gene sequence analysis were found to be the members of the genera Pseudomonas and Agrobacterium belonging to alpha- and gamma-Proteobacteria groups. These strains were also efficient in producing IAA and ACC deaminase though they produced low levels of ethylene and no phosphate solubilization. In addition, inoculation of selected diazotrophic bacterial strains significantly increased seedling length, dry weight, and total nitrogen when compared to uninoculated control. The colonization of crop plants by diazotrophic bacteria can be affected by many biotic and abiotic factors, and further studies are oriented towards investigating the factors that could influence the establishment of a selected bacterial community.

The rates of G:C[yields]T:A and G:C[yields]C:G transversions at CpG dinucleotides in the human factor IX gene

Energy Technology Data Exchange (ETDEWEB)

Ketterling, R.P.; Vielhaber, E.; Sommer, S.S. (Mayo Clinic/Foundation, Rochester, MN (United States))

1994-05-01

The authors have identified eight independent transversions at CpG in 290 consecutive families with hemophilia B. These eight transversions account for 16.3% of all independent transversions in the sample, yet the expected frequency of CpG transversions at random in the factor IX gene is only 2.6% (P<0.1). The aggregate data suggest that the two types of CpG transversions (G:C[yields]T:A and G:C[yields]C:G) possess similar mutation rates (24.8 [times] 10[sup [minus]10] and 20.6 [times] 10[sup [minus]10], respectively), which are about fivefold greater than the comparable rates for transversions at non-CpG dinucleotides. The enhancement of transversions at CpG suggest that the model by which mutations occur at CpG may need to be reevaluated. The relationship, if any, between deamination of 5-methyl cytosine and enhancement of transversions at CpG remains to be defined. 28 refs., 2 tabs.

Polymorphism and methylation of the MC4R gene in obese and non-obese dogs.

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Mankowska, Monika; Nowacka-Woszuk, Joanna; Graczyk, Aneta; Ciazynska, Paulina; Stachowiak, Monika; Switonski, Marek

2017-08-01

The dog is considered to be a useful biomedical model for human diseases and disorders, including obesity. One of the numerous genes associated with human polygenic obesity is MC4R, encoding the melanocortin 4 receptor. The aim of our study was to analyze polymorphisms and methylation of the canine MC4R in relation to adiposity. Altogether 270 dogs representing four breeds predisposed to obesity: Labrador Retriever (n = 187), Golden Retriever (n = 38), Beagle (n = 28) and Cocker Spaniel (n = 17), were studied. The dogs were classified into three groups: lean, overweight and obese, according to the 5-point Body Condition Score (BCS) scale. In the cohort of Labradors a complete phenotypic data (age, sex, neutering status, body weight and BCS) were collected for 127 dogs. The entire coding sequence as well as 5' and 3'-flanking regions of the studied gene were sequenced and six polymorphic sites were reported. Genotype frequencies differed considerably between breeds and Labrador Retrievers appeared to be the less polymorphic. Moreover, distribution of some polymorphic variants differed significantly (P C, c.868C>T and c.*33C>G) and Beagles (c.-435T>C and c.637G>T). On the contrary, in Labradors no association between the studied polymorphisms and BCS or body weight was observed. Methylation analysis, using bisulfite DNA conversion followed by Sanger sequencing, was carried out for 12 dogs with BCS = 3 and 12 dogs with BCS = 5. Two intragenic CpG islands, containing 19 cytosines, were analyzed and the methylation profile did not differ significantly between lean and obese animals. We conclude that an association of the MC4R gene polymorphism with dog obesity or body weight is unlikely, in spite of the fact that some associations were found in small cohorts of Beagles and Golden Retrievers. Also methylation level of this gene is not related with dog adiposity.

Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity

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Lee, Jae-Geun; Kang, Dong Gu; Yu, Jung Re; Kim, Youngree; Kim, Jinsoek; Koh, Gwanpyo

2011-01-01

Background Dipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents. Methods Fasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects. Results ADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; PADA activity was correlated with fasting plasma glucose (r=0.258, P9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; PADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; PADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect. PMID:21738897

Changes in Adenosine Deaminase Activity in Patients with Type 2 Diabetes Mellitus and Effect of DPP-4 Inhibitor Treatment on ADA Activity.

Science.gov (United States)

Lee, Jae-Geun; Kang, Dong Gu; Yu, Jung Re; Kim, Youngree; Kim, Jinsoek; Koh, Gwanpyo; Lee, Daeho

2011-04-01

Dipeptidyl peptidase 4 (DPP-4, also known as CD26) binds with adenosine deaminase (ADA) to activate T lymphocytes. Here, we investigated whether ADA activity is specifically affected by treatment with DPP-4 inhibitor (DPP4I) compared with other anti-diabetic agents. Fasting ADA activity, in addition to various metabolic and biochemical parameters, were measured in 262 type 2 diabetes mellitus (T2DM) patients taking various anti-diabetic agents and in 46 non-diabetic control subjects. ADA activity was increased in T2DM patients compared with that in non-diabetic control subjects (mean±standard error, 23.1±0.6 U/L vs. 18.6±0.8 U/L; PADA activity was correlated with fasting plasma glucose (r=0.258, P9%) showed significantly increased ADA activity (21.1±0.8 U/L vs. 25.4±1.6 U/L; PADA activity in T2DM patients did not differ from those of other oral anti-diabetic agents or insulin. T2DM patients on metformin monotherapy showed a lower ADA activity (20.9±1.0 U/L vs. 28.1±2.8 U/L; PADA activity is increased in T2DM patients compared to that in non-diabetic patients, is positively correlated with blood glucose level, and that DPP4I has no additional specific effect on ADA activity, except for a glycemic control- or HbA1c-dependent effect.