Search results for "rase"
showing 10 items of 4343 documents
Spontaneous Quinolone Resistance in the Zoonotic Serovar of Vibrio vulnificus
2009
ABSTRACT This work demonstrates that Vibrio vulnificus biotype 2, serovar E, an eel pathogen able to infect humans, can become resistant to quinolone by specific mutations in gyrA (substitution of isoleucine for serine at position 83) and to some fluoroquinolones by additional mutations in parC (substitution of lysine for serine at position 85). Thus, to avoid the selection of resistant strains that are potentially pathogenic for humans, antibiotics other than quinolones must be used to treat vibriosis on farms.
The Translesion Polymerase Rev3L in the Tolerance of Alkylating Anticancer Drugs
2009
Temozolomide and fotemustine, representing methylating and chloroethylating agents, respectively, are used in the treatment of glioma and malignant melanoma. Because chemoresistance of these tumors is a common phenomenon, identification of the underlying mechanisms is needed. Here we show that Rev3L, the catalytic subunit of the translesion DNA polymerase zeta, mediates resistance to both temozolomide and fotemustine. Rev3L knockout cells are hypersensitive to both agents. It is remarkable that cells heterozygous for Rev3L showed an intermediate sensitivity. Rev3L is not involved in the tolerance of the toxic O6-methylguanine lesion. However, a possible role of Rev3L in the tolerance of O6-…
Cisplatin-induced endoreduplication in CHO cells: DNA damage and inhibition of topoisomerase II.
2006
It has been proposed that polyploid cells that arise during a variety of pathological conditions and as a result of exposure to genotoxicants, typically in the liver, become aneuploid through genetic instability. Aneuploidy contributes to, or even drives, tumour development. We have assessed the capacity of the drug cisplatin, one of the most commonly used compounds for the treatment of malignancies, to induce endoreduplication, a particular type of polyploidy, in cultured Chinese hamster AA8 cells. Taking into account that any interference with DNA topoisomerase II (topo II) function leads to endoreduplication, we have found that treatment of the cells with this platinum compound results i…
The DNA topoisomerase II catalytic inhibitor merbarone is genotoxic and induces endoreduplication
2012
Abstract In the last years a number of reports have shown that the so-called topoisomerase II (topo II) catalytic inhibitors are able to induce DNA and chromosome damage, an unexpected result taking into account that they do not stabilize topo II-DNA cleavable complexes, a feature of topo II poisons such as etoposide and amsacrine. Merbarone inhibits the catalytic activity of topo II by blocking DNA cleavage by the enzyme. While it was first reported that merbarone does not induce genotoxic effects in mammalian cells, this has been challenged by reports showing that the topo II inhibitor induces efficiently chromosome and DNA damage, and the question as to a possible behavior as a topo II p…
The molecular characterization of a depurinated trial DNA sample can be a model to understand the reliability of the results in forensic genetics
2014
The role of DNA damage in PCR processivity/fidelity is a relevant topic in molecular investigation of aged/forensic samples. In order to reproduce one of the most common lesions occurring in postmortem tissues, a new protocol based on aqueous hydrolysis of the DNA was developed in vitro. Twenty-five forensic laboratories were then provided with 3.0 μg of a trial sample (TS) exhibiting, in mean, the loss of 1 base of 20, and a molecular weight below 300 bp. Each participating laboratory could freely choose any combination of methods, leading to the quantification and to the definition of the STR profile of the TS, through the documentation of each step of the analytical approaches selected. …
The Histone Deacetylase Inhibitor JAHA Down-Regulates pERK and Global DNA Methylation in MDA-MB231 Breast Cancer Cells
2015
The histone deacetylase inhibitor N-1-(ferrocenyl)-N-8-hydroxyoctanediamide (JAHA) down-regulates extracellular-signal-regulated kinase (ERK) and its activated form in triple-negative MDA-MB231 breast cancer cells after 18 h and up to 30 h of treatment, and to a lesser extent AKT and phospho-AKT after 30 h and up to 48 h of treatment. Also, DNA methyltransferase 1 (DNMT1), 3b and, to a lesser extent, 3a, downstream ERK targets, were down-regulated already at 18 h with an increase up to 48 h of exposure. Methylation-sensitive restriction arbitrarily-primed (MeSAP) polymerase chain reaction (PCR) analysis confirmed the ability of JAHA to induce genome-wide DNA hypomethylation at 48 h of expos…
Comparison of DNase, DNA-polymerase and RNA-polymerase activities present in the DNA-bindung proteins of normal human dermis, epidermis, horny layer …
1978
DNA-binding proteins (DBP) of normal human dermis, epidermis, horny layer and psoriatic scales represent a tissue-specific group of mostly nuclear nonhistone proteins. To analyse their function, the different DBP fractions were examined concerning the presence of DNase, DNA-polymerase and RNA-polymerase activities. DBP of normal epidermis and horny layer contain four different DNases. One DNase of both DBP fractions is active only at pH 5.0. Three DNases of epidermal DBP are active at a pH-range from 5.0--8.5, while the corresponding DNases of horny layer-DBP are most active at pH 7.4. Probably these DNases have changed their pH-optimum during keratinisation. DBP of psoriatic scales include…
Mutations in CTC1, encoding conserved telomere maintenance component 1, cause Coats plus
2012
Coats plus is a highly pleiotropic disorder particularly affecting the eye, brain, bone and gastrointestinal tract. Here, we show that Coats plus results from mutations in CTC1, encoding conserved telomere maintenance component 1, a member of the mammalian homolog of the yeast heterotrimeric CST telomeric capping complex. Consistent with the observation of shortened telomeres in an Arabidopsis CTC1 mutant and the phenotypic overlap of Coats plus with the telomeric maintenance disorders comprising dyskeratosis congenita, we observed shortened telomeres in three individuals with Coats plus and an increase in spontaneous γ 3H2AX-positive cells in cell lines derived from two affected individual…
Association of hepatitis Be antigen (HBeAg) with the core of the hepatitis B virus (HBcAg).
2008
— Three substances (pronase E, sodium dodecylsulfate (SDS) and guanidine hydrochloride) with different chemical actions partially convert HBcAg to HBeAg. This process retains the integrity of the HBcAg particle, which was not different between HBcAg subpopulations, and does not generate HBcAg or HBeAg sub-units. DNA polymerase activity was destroyed by SDS and guanidine hydrochloride, but not by pronase E. Serum HBeAg could not be converted into HBcAg, suggesting that this might be an irreversible process. The data are consistent with the assumption that HBcAg and HBeAg are coded for by the same gene (C gene of the HBV-DNA).
Inhibitors acting on nucleic acid synthesis in an oncogenic RNA virus.
1971
IN infection with an oncogenic RNA virus, synthesis of viral RNA seems to be catalysed by an RNA dependent DNA polymerase in the host cell1–4. Several specific inhibitors of viral DNA polymerases have been found5–7 and Spiegelman8 has shown that the activity of viral enzymes depends strongly on the chemical composition of the template. We report here first a new highly specific poison of the Rauscher murine leukaemia virus (RMLV) DNA polymerases; second, several inactivators of the RNA and DNA template involved in the RMLV enzyme systems; and third, the action of actinomycin D on viral DNA polymerases and on host DNA/RNA polymerase. The results are discussed with respect to the influence of…