Search results for "Polymerases"
showing 10 items of 66 documents
A genome-wide transcriptional study reveals that iron deficiency inhibits the yeast TORC1 pathway
2019
Iron is an essential micronutrient that participates as a cofactor in a broad range of metabolic processes including mitochondrial respiration, DNA replication, protein translation and lipid biosynthesis. Adaptation to iron deficiency requires the global reorganization of cellular metabolism directed to optimize iron utilization. The budding yeast Saccharomyces cerevisiae has been widely used to characterize the responses of eukaryotic microorganisms to iron depletion. In this report, we used a genomic approach to investigate the contribution of transcription rates to the modulation of mRNA levels during adaptation of yeast cells to iron starvation. We reveal that a decrease in the activity…
Pyrrolotetrazinones deazaanalogues of temozolomide induce apoptosis in Jurkat cell line: involvement of tubulin polymerization inhibition.
2009
Pyrrolotetrazinones are a new class of azolotetrazinones endowed with a high, remarkable antiproliferative activity in human tumor cultured cells. They hold the deaza skeleton of the antitumor drug temozolomide, although preliminary investigations indicated a different mechanism of action. To understand their mechanism(s) of action along with their target at molecular level, four derivatives were selected on the basis of their activity on a panel of human tumor cell lines and they were investigated in depth in a T leukemia cell line (Jurkat). Flow cytometric analysis of cell cycle after treatment with pyrrolotetrazinones has demonstrated that they were able to induce an arrest of the cell c…
A novel form of ataxia oculomotor apraxia characterized by oxidative stress and apoptosis resistance
2007
Several different autosomal recessive genetic disorders characterized by ataxia with oculomotor apraxia (AOA) have been identified with the unifying feature of defective DNA damage recognition and/or repair. We describe here the characterization of a novel form of AOA showing increased sensitivity to agents that cause single-strand breaks (SSBs) in DNA but having no gross defect in the repair of these breaks. Evidence for the presence of residual SSBs in DNA was provided by dramatically increased levels of poly (ADP-ribose)polymerase (PARP-1) auto-poly (ADP-ribosyl)ation, the detection of increased levels of reactive oxygen/nitrogen species (ROS/RNS) and oxidative damage to DNA in the patie…
Acute ammonia intoxication induces an NMDA receptor-mediated increase in poly(ADP-ribose) polymerase level and NAD+ metabolism in nuclei of rat brain…
2004
Acute ammonia toxicity is mediated by excessive activation of NMDA receptors. Activation of NMDA receptors leads to activation of poly(ADP-ribose) polymerase (PARP) which mediates NMDA excitotoxicity. PARP is activated following DNA damage and may lead to cell death via NAD+ and ATP depletion. The aim of the present work was to assess whether acute ammonia intoxication in vivo leads to increased PARP in brain cells nuclei and to altered NAD+ and superoxide metabolism and the contribution of NMDA receptors to these alterations. Acute ammonia intoxication increases PARP content twofold in brain cells nuclei.NAD+ content decreased by 55% in rats injected with ammonia. This was not due to decre…
Mutations in the rpoB and katG Genes Leading to Drug Resistance in Mycobacterium tuberculosis in Latvia
2002
ABSTRACT To characterize the genetic basis of drug resistance in Mycobacterium tuberculosis in Latvia, mutations involved in rifampin ( rpoB gene) and isoniazid ( katG gene) resistance in DNA from 19 drug-susceptible and 51 multidrug-resistant M. tuberculosis complex isolates were analyzed. The most frequent rpoB gene mutations found by the Line Probe assay were the S531L (14 of 34 isolates), D516V (7 of 34), H526D (4 of 34), and D516Y plus P535S (4 of 34) mutations. Direct sequencing of seven isolates with unclear results from Line Probe assay showed the presence of the L533P mutation and the Q510H plus H526Y (1 of 34) and D516V plus P535S (4 of 34) double mutations, neither of which has b…
Incidence, Diversity, and Molecular Epidemiology of Sapoviruses in Swine across Europe▿
2010
ABSTRACT Porcine sapovirus is an enteric calicivirus in domestic pigs that belongs to the family Caliciviridae . Some porcine sapoviruses are genetically related to human caliciviruses, which has raised public health concerns over animal reservoirs and the potential cross-species transmission of sapoviruses. We report on the incidence, genetic diversity, and molecular epidemiology of sapoviruses detected in domestic pigs in a comprehensive study conducted in six European countries (Denmark, Finland, Hungary, Italy, Slovenia, and Spain) between 2004 and 2007. A total of 1,050 swine fecal samples from 88 pig farms were collected and tested by reverse transcription-PCR for sapoviruses, and pos…
Social evolution of innate immunity evasion in a virus
2019
Antiviral immunity has been studied extensively from the perspective of virus−cell interactions, yet the role of virus−virus interactions remains poorly addressed. Here, we demonstrate that viral escape from interferon (IFN)-based innate immunity is a social process in which IFN-stimulating viruses determine the fitness of neighbouring viruses. We propose a general and simple social evolution framework to analyse how natural selection acts on IFN shutdown and validate it in cell cultures and mice infected with vesicular stomatitis virus. Furthermore, we find that IFN shutdown is costly because it reduces short-term viral progeny production, thus fulfilling the definition of an altruistic tr…
Molecular Epidemiology of Caliciviruses Causing Outbreaks and Sporadic Cases of Acute Gastroenteritis in Spain
2002
ABSTRACT The molecular epidemiology of human caliciviruses (HuCVs) causing sporadic cases and outbreaks of acute gastroenteritis around eastern Spain (Catalonia and the Valencian Community) was studied by reverse transcription-PCR (RT-PCR) and by sequencing part of the RNA polymerase gene in open reading frame 1. HuCVs were detected in 44 of 310 stool specimens (14.19%) negative for other enteric pathogens obtained from children with acute gastroenteritis. Norwalk-like viruses (NLVs) were the most common cause of the gastroenteritis outbreaks investigated here. They were detected in 14 out of 25 (56%) outbreaks with an identified pathogen. Genotypes producing both sporadic cases and outbrea…
Genes, Ageing and Longevity in Humans: Problems, Advantages and Perspectives.
2006
Many epidemiological data indicate the presence of a strong familial component of longevity that is largely determined by genetics, and a number of possible associations between longevity and allelic variants of genes have been described. A breakthrough strategy to get insight into the genetics of longevity is the study of centenarians, the best example of successful ageing. We review the main results regarding nuclear genes as well as the mitochondrial genome, focusing on the investigations performed on Italian centenarians, compared to those from other countries. These studies produced interesting results on many putative "longevity genes". Nevertheless, many discrepancies are reported, l…
Determination of enrichment factors for modified RNA in MeRIP experiments
2019
In the growing field of RNA modification, precipitation techniques using antibodies play an important role. However, little is known about their specificities and protocols are missing to assess their effectiveness. Here we present a method to assess enrichment factors after MeRIP-type pulldown experiments, here exemplified with a commercial antibody against N6-methyladenosine (m6A). Testing different pulldown and elution conditions, we measure enrichment factors of 4-5 using m6A-containing mRNAs against an unmodified control of identical sequence. Both types of mRNA carry 32P labels at different nucleotides, allowing their relative quantification in a mixture after digestion to nucleotides…