Academic literature on the topic 'Demetylace'

Investigations were carried out on intact leaves of <i>Nicotiana alata</i> which contain practically not alkaloids. Whey these leaves are infiltrated with nicotine it undergoes some chemical changes rather quickly. After introducing the nicotine into the leaves the alkaloid composition was investigated in three day intervals after the infiltration was stopped. No oxynicotine was present in the investigated material. The formation of nornicotine was determined quantitatively in outer and internal layers of the leaf blade. On the basis of these results determination of order and rate of nicotine demethylation was attempted. The reaction was classifield as a first order monomolecular reaction. In this connection a presumed mechanism of nicotine demethylation in leaves of <i>Nicotiana alata</i> was discussed.

Seborrheic dermatitis (SD) occurs due to excessive sebum production resulting in the growth of the fungus Mellasezia sp. on the skin becomes uncontrollable. Some of the receptors that play a role in SD regulation are Low Density Lipoprotein (LDL) protein, Lanasterol 14-α Demetylase enzyme, and Lipase enzyme. This study aims to determine the potential compounds of the endophytic fungi Trichoderma sp. as an antiseborrheic and knowing the interaction between ligands as inhibitors in SD regulation. The research was conducted with computer-based molecular docking. The results showed that there were two inhibitor candidate compounds based on the selection by binding affinity value, namely Chloromycetin and Benzyl benzoate. Based on the results of docking with VINA autodock, the potential compounds were Benzyl benzoate on LDL protein with binding affinity values of -7.3 kcal/mol, compounds were Chloromycethin on Lipase enzyme with binding affinity values of -7.3 kcal/mol and Lanasterol 14-α demethylase enzyme with a binding affinity value of -7.6 kcal/mol. These compounds form hydrogen bonds and hydrophobic bonds. Based on the prediction of Lipinski's rule of five, the two compounds are effective orally used as anti seborrheic dermatitis drugs

Ekspresja genów w komórkach jest ściśle kontrolowana i podlega regulacji m.in. za pomocą mechanizmów epigenetycznych takich jak metylacja DNA, modyfikacje histonów, pozycjonowanie nukleosomów czy niekodujące RNA. Deregulacja mechanizmów epigenetycznych odgrywa kluczową rolę w procesie nowotworzenia, przy czym naukowcy spierają się czy zjawisko to jest przyczyną czy też konsekwencją rozwoju nowotworu. W wyniku deregulacji mechanizmów epigenetycznych w komórce następują głębokie zmiany w ekspresji genów zarówno na poziomie RNA jak i białka. W wyniku zmian epigenetycznych dochodzi najczęściej do zwiększonej proliferacji komórek, wzrostu nowotworu i przerzutowania. Większość zmian epigenetycznych w komórce takich jak nieprawidłowe wzory metylacji DNA czy modyfikacji histonówjest wynikiem mutacji w genach odpowiedzialnych za ich wprowadzanie lub usuwanie. Mutacje w genach regulujących pozycjonowanie nukleosomów prowadzą do zmian w organizacji genomu w jądrze, a w konsekwencji do mutacji na poziomie chromosomu, takich jak translokacje czy zmiany liczby kopii genu w komórce. Ponadto, zaobserwowano również mutacje w genach metabolizmu komórkowego, które mogą wpływać na aktywność genów odpowiedzialnych za demetylację DNA lub modyfikacje histonów. Rozwój technik sekwencjonowania cało genomowego umożliwił poznanie globalnych zmian w profilu epigenetycznym komórek nowotworowych.

Epidemiological investigations in representative chickpea (Cicer arietinum L.) fields in southern Italy (Larino, Campobasso, 41°50′45″ N, 14°55′28″ E) identified severe withering (25 to 51%) of plants during flowering. Diseased plants showed a reduced total root biomass associated with less vigorous and chlorotic foliage. Browning and necrosis of subcortical and xylematic tissues of the crown and main roots were observed in affected plants. Symptomatic root and stem portions from 50 plants were sampled, surface disinfected with a sodium hypochlorite water solution (2% v/v for 2 min), rinsed with sterile distilled water, and placed in petri dishes containing potato dextrose agar with streptomycin sulfate (200 mg/l) and incubated at 25°C for 10 days. The most frequent fungal colony isolated showed macro- and microscopic characters specific of the genus Fusarium (3), with falcate and three-septate macroconidia (24.0 to 43.8 μm long) and microconidia (6.8 to 10.4 μm long) with zero or one septa. The ribosomal DNA of the fungal isolate processed by PCR using the ITS1F/ITS4 primers (2) produced an amplicon of 545 bp (ENA, Accession No. HG423346). A BLAST search with the amplified sequence in the database of the International Mycological Association ( www.mycobank.org ) revealed 99% identity with F. oxysporum sequences. Additional molecular analysis using the specific primers Foc0-12/Foc0-12rf for F. oxysporum f.sp. ciceris (Foc) produced an amplicon only in the chickpea virulent strain Foc-7952, race 0 (1) used as control; furthermore, PCR amplification for the Pisatin Demetylase gene by using the specific primers PDAF2a and PDAR3a (4) yielded the expected amplicon only for the new isolate, whereas no amplification was obtained with the control strain Foc-7952. Pathogenicity assays were carried out to complete Koch's postulates. To this aim, horticultural peat was infested with a conidial suspension (1 × 104 conidia/g of soil) from the new fungal pathogen, dispensed in plastic pots, and sown with surface sterilized seeds of chickpea (cv. Real, ISEA, Italy). Uncontaminated peat was used as control. For both treatments, 3 replicates of 10 seeds were used and experiments repeated twice. The plastic pots were kept in a growth chamber (28°C; 70% RH; 15/9 h light/dark) where the first disease symptoms on plants appeared 20 days after sowing. At the end of the experiments, all plants inoculated with the new isolate showed a high disease severity (98%), whereas non-inoculated plants remained healthy. The seedlings from infested soil demonstrated the same symptoms previously observed in the field, and after re-isolation, the causal agent demonstrated the same morphological features of the isolate used for inoculation. Pathogenicity tests were performed on pea, faba bean, melon, and tomato by using three cultivars for each crop. The results demonstrated high virulence of the new isolate of F. oxysporum f.sp. pisi (Fop) on both chickpea and pea with seed germination reduction, rot on main and secondary roots and cotyledonary leaves, and root biomass reduction and foliage chlorosis. No symptoms were observed on other inoculated vegetal species. Collectively, data of our investigation allow us to affirm that this is the first report of Fop as a new pathogen of chickpea. This result has great economic importance since it enables specific monitoring and management plans for this new disease caused by Fop on chickpea, a key crop for human and animal nutrition. References: (1) M. M. Jiménez-Gasco and R. M. Jiménez-Díaz, Phytopathology 93:201, 2003. (2) I. Larena et al. J. Biotechnol. 75:187, 1999. (3) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Ames, IA, 2006. (4) N. A. Milani et al. Fungal Genet. Biol. 933:942, 2012.

Abstract Abstract 1206 Introduction: Induced pluripotent stem cells (iPSCs) can be generated from various cell types by the expression of defined transcription factors. In addition to the regenerative medicine, iPSCs have been used for the study of the pathogenesis of inherited genetic disease. Recently, it was reported that iPSCs were generated not only from normal tissue, but also from malignant cells. In those cases, cancer cells themselves must be the starting material from which iPSCs are derived. However, in almost all the cases, they used the established cell lines (chronic myelogenous leukemia (CML), gastrointestinal cancers, and melanoma) except for the JAK2-V617F mutation (+) polycythemia vera (PV) patient. In this study, we established the iPSCs from primary CML patient sample. Results: After obtaining informed consent, bone marrow cells from CML patient were reprogrammed by introducing the transcription factors Oct3/4, Sox2, KLF4, and c-myc. To improve the efficiency of the development of iPSCs, we added valproic acid (VPA), a histone deacetylase inhibitor, to the culture. Two CML derived iPSCs (CML-iPSCs) were generated. CML-iPSCs expressed the pluripotency markers such as SSEA-4 and Tra-1-60, and the endogenous expression of embryonic stem cell (ESC) characteristic transcripts (Oct3/4, Sox2, KLF4, Nanog, LIN28, REX1) was confirmed by RT-PCR. Oct4 and Nanog promoter regions were demetylated in the CML-iPSCs. Although CML-iPSCs expressed bcr-abl, they were resistant to the imatinib. Then we differentiated them into hematopoietic progenitors within the ‘unique sac-like structures’ (iPS-sacs). This method was reported to be able to produce the hematopoietic progenitors with higher efficiency than the usual embryoid body formation method using human ESCs (Takayama et al., Blood, 111, 5298–306, 2008). The hematopoietic progenitors showed the hematopoietic marker CD45 and immature marker CD34, and recovered the sensitivity to the imatinib, which recapitulated the feature of initial CML disease. Then we investigated the mechanism of the resistance to the imatinib in CML-iPSCs. The phosphorylation state of ERK1/2, AKT, and STAT5, which are the essential for the survival of bcr-abl (+) hematopoietic progenitors, were evaluated after imatinib treatment in CML-iPSCs. The phosphorylation of ERK1/2 and AKT, which were also essential for the maintenance of iPSCs, were unchanged after treatment, although STAT5 was not activated both before and after treatment. These results showed that the signaling for iPSCs maintenance compensated for the inhibition of bcr-abl in CML-iPSCs and that the oncogene addiction was lost in CML-iPSCs. Conclusion: We generated the iPSCs from primary CML patient samples, re-differentiated them into hematopoietic lineage and showed the recapitulation of the features of initial disease. Primary samples of hematological malignancy are usually difficult to be expanded. However, if once they are reprogrammed to iPSCs, they can expand unlimitedly. As a result, we can obtain the genetically abnormal hematopoietic cells continuously by re-differentiating them into hematopoietic cells and use them for the studies which require the large number of living cells such as the analysis for leukemia stem cells or drug screening. Thus iPSCs technology would be useful for the study of hematological malignancy, especially for which animal model was not established such as myelodysplastic syndrome and be applicable for other cancers than hematological malignancies. We are now trying to establish the iPSCs derived from other hematological malignancies. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 1345 Background: Among the subtypes of acute myeloid leukemia (AML), acute promyelocytic leukemia (APL) responds dramatically to differentiation therapy with all-trans retinoic acid (ATRA). However, ATRA is not sufficient to induce differentiation in non-APL AML. Although the molecular basis for the poor response of non-APL AML to ATRA was poorly understood, Lysine-specific demethylase 1 (LSD1), the histone demetylase, was found to inhibit the retinoic acid pathway by chromatin modification through H3K4 demethylation, resulting in silencing of gene expression targeted by retinoic acid. Herein, we first evaluated whether MLL fusion partners, such as MLL-AF9 and MLL-AF4/AF5q31, affect the sensitivity of ATRA in human and murine MLL fusion positive AML cells, which is one of the most aggressive pediatric AML. In addition, we also assess whether the LSD1 inhibitor affects the ATRA sensitivity in MLL fusion positive AML cells. Methods: Three human AML cell lines with MLL fusion (THP-1 and MOLM-13 expressing MLL-AF9, and KOCL48 expressing MLL-AF4) and two murine leukemic cell lines derived from murine Lin- hematopoietic progenitors transduced by retroviral vector expressing MLL fusion genes, such as MLL-AF9 and MLL-AF5q31 were used in this study. To test the sensitivity of ATRA, all cell lines were treated with 1 μM ATRA for three days. Cell growth was analyzed by counting nuclei using a Coulter counter. Monocytic differentiation was assessed by morphological analysis, NBT reduction test and flow cytometric analysis (FCM) of CD11b expression. FCM analysis was also carried out to evaluate cell cycle and annexin V assay. Quantitative RT-PCR (qRT-PCR) analysis and western blotting was carried out to measure the RARα, C/EBPα, C/EBPε, and PU.1 expressions. To determine whether Tranylcypromine (TCP), which is a nonreversible LSD1 inhibitor, could decrease the IC50 of ATRA in MLL-AF4/AF5q31 positive cells, KOCL48 and murine MLL-AF5q31 expressing cells were treated with 0μM or 10μM TCP and titrating doses of ATRA (ranging from 0μM to 10μM). After three days, cell count was analyzed by counting nuclei using a Coulter counter to evaluate IC50 of ATRA in each cell lines. Results: We first determined that morphological changes characteristic of monocytic differentiation, CD11b expression and NBT reduction are more readily induced by ATRA in human and murine MLL-AF9 positive cells than human and murine MLL-AF4/AF5q31 positive cells The NBT reduction percentage was 17.6±1.69 in THP-1, but 2.7±1.2 in KOCL48 cells (p<0.01). The ATRA treatment also induced growth inhibition accompanied with G0/G1 arrest and apoptosis more efficiency in MLL-AF9 positive cells than MLL-AF4/AF5q31 cells. The IC50 of ATRA for THP-1 cells was 0.21±0.04 μM, but 5.31±1.50 μM for KOCL48 cells (p<0.01) The percentage of cells arrested in G0/G1 phase and Annexin/PI positive cells were 84% and 17.8% in THP-1 but 40% and 4.8% in KOCL48, respectively. Furthermore, qRT-PCR analysis and western blot analysis revealed that ATRA increased expression level of RARα, C/EBPα, C/EBPε, and PU.1, which is involved in monocytic differentiation through retinoic acid pathway, in MLL-AF9 positive cells, but not in MLL-AF4/AF5q31 positive cells. Collectively, retinoic acid pathway is more impaired in MLL-AF4/AF5q31 positive cells than MLL-AF9 positive cells. Next, we also determined that ATRA and TCP combination treatment suppressed cell growth and decreased the IC50 of ATRA in KOCL48 and murine MLL-AF5q31 expressing cells (IC50 of ATRA: 0.20±0.10 μM and 0.20±0.09 μM with TCP, vs 5.5±3.2 μM and over 10 μM without TCP, p<0.05), accompanied with morphological changes and CD11b expression, suggesting that inhibition of LSD1 restores ATRA sensitivity in both cell lines. Conclusions: Our data demonstrate that retinoic acid pathway was more profoundly impaired in MLL-AF4/AF5q31 positive cell than MLL-AF9 positive cells, suggesting MLL-AF4/AF5q31 contributes inactivation of retinoic acid pathway. Our data also demonstrate TCP restore the sensitivity of ATRA in ATRA-resistant MLL-AF4/AF5q31 positive cell lines, suggesting LSD1 plays a major role in inactivation of retinoic acid pathway in MLL-AF4/AF5q31 positive cells. Therefore, LSD1 inhibitor might be important novel therapeutic option for differentiation therapy of MLL-fusion positive AML, especially for ATRA resistant MLL-AF4/AF5q31 positive cells. Disclosures: No relevant conflicts of interest to declare.

Rtuť je v přírodě přirozeně se vyskytujícím toxickým prvkem, jehož globální emise jsou ovlivňovány zejména antropogenními zdroji znečištění. Obrovský globální nárůst v usazování rtuti, zejména ve vodných ekosystémech, byl zaznamenán současně s počátkem průmyslové revoluce. Sedimenty jsou posledním místem úložiště nejrůznějších komplexů rtuti. Rtuť však zde může být přeměněna na toxičtější organickou formu, methylrtuť, pomocí transformačních procesů kontrolovaných různými fyzikálními, chemickými, ale i biologickými faktory. Navíc mohou být specie rtuti remobilizovány ze sedimentů pomocí difuze a resuspenzace a tak se sedimenty mohou stát i potenciálním zdrojem rtuti. Proces bioakumulace a bioobohacování tak pokračuje v potravním řetězci, ve kterém se člověk, i další zvířata, stává konzumentem methylrtuti. Stanovení celkové koncentrace rtuti není dostačující k porozumění osudu rtuti v přírodním prostředí a tak stanovení MeHg poskytuje nezbytnou doplňující informaci. Dostatečně citlivá a přesná analytická metoda pro stanovení specií rtuti je nezbytným nástrojem environmentální chemie. Metody vhodné pro stanovení specií rtuti v sedimentech jsou popsány v části metodologie disertační práce. Metoda stanovení methylrtuti v sedimentech pomocí automatické Headspace vybavené pastí („trap“) a spojené s plynovou chromatografií a fluorescenční detekcí je zde také popsána. Zvláštní pozornost je také věnována potřebám zásad čistého vzorkování, skladování vzorků a přípravě vzorků před samotou analýzou, jakož i samostatné části věnující se terénní studii rtuti a methylrtuti v sedimentech vytipovaných lokalit. Sedimenty jižní Moravy a severní Francie jsou srovnány z hlediska znečištění rtutí. Specie rtuti a další ukazatele (Fe, Mn, S) byly analyzovány v sedimentech, pórové vodě a povrchové vodě řek Dele a Lys (Francie) a Jihlava a Morava (Česká republika). Z hlediska posouzení vodních ekosystémů a jejich znečištění rtutí, je vhodné znát koncentraci rtuti v pórové vodě a posoudit dostupnost rtuti ze sedimentů. Technika difuzního gradientu v tenkém filmu je vhodným způsobem jak stanovit koncentraci rtuti v pórové vodě sedimentů. Do roku 2005 bylo použití této techniky pro měření rtuti značně limitováno. Ale nedávný pokrok především v dostupnosti možných sorpčních gelů vhodných pro stanovení rtuti umožnilo využití této techniky i pro stanovení rtuti. Byly použity různé sorpční gely: Spheron.Thiol, Duolite GT-73 a TiO2. Řeka Dele představuje past enormního množství antropogenní rtuti pocházející z průmyslových zdrojů a je považována za potenciální významný zdroj methylrtuti pro okolní prostředí a živé organismy především. Poslední část dizertační práce se zabývá aplikací dobře zavedeného experimentu využívajícím stabilní isotopy ke studiu metylačních a demethylačních procesů v sedimentech řeky Dele. Obohacené stabilní značkovače rtuti v anorganické formě (199Hg) and methylované formě (201MeHg) byly přidány do sedimentů. Tyto označené specie rtuti tak pomohly sledovat osud specií rtuti a vypočítat rozsah jejich přeměny v průběhu experimentu.