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    Wyświetlanie 1-14 z 14
    Tytuł:
    Hydrolysis of cyclic GMP in rat peritoneal macrophages.
    Autorzy:
    Witwicka, Hanna
    Kobiałka, Marcin
    Gorczyca, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1043691.pdf
    Data publikacji:
    2002
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    signal transduction
    phosphodiesterases
    cyclic nucleotides
    macrophages
    Opis:
    Intact rat peritoneal macrophages (rPM) treated with 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases (PDEs), accumulated more cGMP than untreated cells. A PDE activity toward [3H]cGMP was detected in the soluble and particulate fractions of rPM. The hydrolysis of cGMP was Ca2+/calmodulin-independent but increased in the presence of cGMP excess. Similar results were obtained when [3H]cAMP was used as a substrate. The hydrolytic activity towards both nucleotides was inhibited in the presence of IBMX. Therefore, the PDEs of families 2, 5, 10 and 11 are potential candidates for cGMP hydrolysis in the rPM. They may not only regulate the cGMP level in a feedback-controlled way but also link cGMP-dependent pathways with those regulated by cAMP.
    Źródło:
    Acta Biochimica Polonica; 2002, 49, 4; 891-897
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effects of galactosamine on UTP levels in the livers of young, adult and old rats.
    Autorzy:
    Kmieć, Zbigniew
    Smoleński, Ryszard
    Zych, Marek
    Myśliwski, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/1044358.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    liver
    UTP
    rat aging
    galactosamine
    nucleotides
    Opis:
    Galactosamine (GalN), a well-known hepatotoxin that depletes the cellular pool of uracil nucleotides, was previously shown to have greater impact on the inhibition of protein synthesis in hepatocytes of old rats as compared with young animals (Kmieć 1994, Ann. N.Y. Ac. Sci. 717, 216-225). In the present study we compared the effects of GalN on the nucleotide content (measured by ion-exchange HPLC) in the livers of young (4 months), adult (12 months), and old (24-26 months old) rats two hours after its intraperitoneal administration. UTP content of the livers of old control rats was significantly lower (by 28%) than that of young animals. GalN administration decreased the UTP content in the livers of young, adult and old rats by, respectively, 55%, 65% and 89%, and increased the content of UDP-sugars by 189%, 175% and 305%. The hepatic content of ATP, ADP, AMP, NAD, GTP except CTP did not differ significantly among the age groups of rats studied, and was not changed by GalN treatment. The content of CTP was significantly higher in old rats (P < 0.03) upon GalN treatment. The lower hepatic content of UTP may partially explain the increased sensitivity of hepatocytes and livers of old rats to the action of galactosamine, and possibly to other hepatotoxic compounds that decrease transcription in the liver.
    Źródło:
    Acta Biochimica Polonica; 2000, 47, 2; 349-353
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Degradation of extracellular nucleotides and their analogs in HeLa and HUVEC cell cultures.
    Autorzy:
    Gendaszewska-Darmach, Edyta
    Maszewska, Maria
    Zakłos, Małgorzata
    Koziołkiewicz, Maria
    Powiązania:
    https://bibliotekanauki.pl/articles/1043368.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    nucleotide analogs
    extracellular nucleotides
    ectoenzymes
    nucleotide pyrophosphatase
    Opis:
    The use of nucleotides and their analogs in the pharmacological studies of nucleotide receptors (P2 class) should be preceded by detailed studies on their degradation connected with ecto-enzymes of a given cell type. In the present studies we have analyzed stability of some phosphorothioate and phosphonate analogs of ATP and ADP in the HeLa epitheloid carcinoma and endothelial HUVEC cells cultures. Our studies have revealed that ecto-nucleotide pyrophosphatase (E-NPP) is one of the main enzymes involved in the extracellular degradation of ATP and other nucleotides in the HeLa cells. On the other hand, the ecto-ATPDase is responsible for the hydrolysis of extracellular nucleotides in human endothelial cell cultures, while the E-NPP-like enzymes of the HUVEC cells are not essential to this degradation. The concerted action of the aforementioned ecto-enzymes and nucleotide pyrophosphatase, 5'-nucleotidase and adenosine deaminase present in fetal bovine serum (FBS) supplied to the culture medium, results in partial or complete degradation of the phosphorothioate (ATPγS) and phosphonate analogs of adenosine nucleotides (α,β-methylene-ATP and β,γ-methylene-ATP) in the cell cultures. Only ADPβS appears to be resistant to these enzymes. The influence of some nucleotides and their analogs on the proliferation of the HeLa cells in presence or absence of FBS is also discussed.
    Źródło:
    Acta Biochimica Polonica; 2003, 50, 4; 973-984
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A new approach to phosphorylation of nucleosides using oxyonium phosphobetaines as intermediates
    Autorzy:
    Materna, Magdalena
    Stawinski, Jacek
    Sobkowski, Michał
    Powiązania:
    https://bibliotekanauki.pl/articles/16673995.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    synthesis
    phosphorylation
    N-oxides
    nucleotides
    oxyonium phosphobetaines
    H-phosphonates
    Opis:
    Oxyonium phosphobetaines are recently discovered molecules with a unique ¯O–P–O–N+ bond system, which makes them useful and versatile intermediates for the synthesis of phosphates and their derivatives. In this paper, the preliminary data on the application of these compounds in nucleoside phosphorylation were presented.
    Źródło:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2023, 104, 1; 93-99
    0860-7796
    Pojawia się w:
    BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Particulate guanylyl cyclases: multiple mechanisms of activation.
    Autorzy:
    Kobiałka, Marcin
    Gorczyca, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1044281.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    signal transduction
    calcium-binding proteins
    guanylyl cyclases
    cyclic nucleotides
    Opis:
    Cyclic GMP (cGMP), a key messenger in several signal transduction pathways, is synthesized from GTP by a family of enzymes termed guanylyl cyclases, which are found in two forms: cytosolic (soluble) and membrane-bound (particulate). The past decade has brought significant progress in understanding the molecular mechanisms that underlie the regulation of particulate guanylyl cyclases and new members of their family have been identified. It has become more evident that the basic mechanism of catalysis of guanylyl cyclases is analogous to that recognized in adenylyl cyclases. Here we review the known basic mechanisms that contribute to the regulation of particulate guanylyl cyclases.
    Źródło:
    Acta Biochimica Polonica; 2000, 47, 3; 517-528
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Building the library of RNA 3D nucleotide conformations using the clustering approach
    Autorzy:
    Zok, T.
    Antczak, M.
    Riedel, M.
    Nebel, D.
    Villmann, T.
    Lukasiak, P.
    Blazewicz, J.
    Szachniuk, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/329744.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    RNA nucleotides
    conformer library
    torsion angles
    clustering
    neural gas
    Opis:
    An increasing number of known RNA 3D structures contributes to the recognition of various RNA families and identification of their features. These tasks are based on an analysis of RNA conformations conducted at different levels of detail. On the other hand, the knowledge of native nucleotide conformations is crucial for structure prediction and understanding of RNA folding. However, this knowledge is stored in structural databases in a rather distributed form. Therefore, only automated methods for sampling the space of RNA structures can reveal plausible conformational representatives useful for further analysis. Here, we present a machine learning-based approach to inspect the dataset of RNA three-dimensional structures and to create a library of nucleotide conformers. A median neural gas algorithm is applied to cluster nucleotide structures upon their trigonometric description. The clustering procedure is two-stage: (i) backbone- and (ii) ribose-driven. We show the resulting library that contains RNA nucleotide representatives over the entire data, and we evaluate its quality by computing normal distribution measures and average RMSD between data points as well as the prototype within each cluster.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 2015, 25, 3; 689-700
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determination of adenine nucleotides and their metabolites in human saliva.
    Autorzy:
    Kochańska, Barbara
    Smoleński, Ryszard
    Knap, Narcyz
    Powiązania:
    https://bibliotekanauki.pl/articles/1044347.pdf
    Data publikacji:
    2000
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    uric acid
    xanthine
    HPLC
    inosine
    saliva
    hypoxanthine
    adenine nucleotides
    Opis:
    The profile and normal concentrations of nucleotide metabolites in human saliva and reproducibility of these determinations were analyzed. Samples of human saliva collected from healthy individuals at weekly intervals, were deproteinized and analysed for the content of adenine nucleotides and their metabolites by reversed-phase HPLC. Initial ATP, hypoxanthine and uric acid concentrations were 0.52 ± 0.15 μM, 1.91 ± 0.37 μM and 184 ± 22 μM respectively. A substantial individual variation persisted within 3 weeks of sampling excepted hypoxanthine which showed some unrelated variations. Determination of nucleotides and their catabolites in saliva due to its simplicity and reproducibility, may be of clinical value in diagnosis of local or systemic disorders.
    Źródło:
    Acta Biochimica Polonica; 2000, 47, 3; 877-879
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Metabolism of cyclic GMP in peritoneal macrophages of rat and guinea pig.
    Autorzy:
    Kobiałka, Marcin
    Witwicka, Hanna
    Siednienko, Jakub
    Gorczyca, Wojciech
    Powiązania:
    https://bibliotekanauki.pl/articles/1043463.pdf
    Data publikacji:
    2003
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    guinea pig
    rat
    signal transduction
    phosphodiesterases
    guanylyl cyclases
    protein kinases
    cyclic nucleotides
    macrophages
    Opis:
    The aim of our studies was to establish which enzymes constitute the "cGMP pathway" in rat and guinea pig peritoneal macrophages (PM). We found that in guinea pig PM synthesis of the nucleotide was significantly enhanced in response to activators of soluble guanylyl cyclase (sGC) and it was only slightly stimulated by specific activators of particulate guanylyl cyclases (pGC). In contrast, rat PM responded strongly to atrial natriuretic peptide (ANP), the activator of pGC type A. The rat cells synthesized about three-fold more cGMP than an equal number of the guinea pig cells. The activity of phosphodiesterases (PDE) hydrolyzing cGMP was apparently regulated by cGMP itself in PM of both species and again it was higher in the rat cells than in those isolated from guinea pig. However, guinea pig PM revealed an activity of Ca2+/calmodulin-dependent PDE1, which was absent in the rat cells. Using Western blotting analysis we were unable to detect the presence of cGMP-dependent protein kinase 1 (PKG1) in PM isolated from either species. In summary, our findings indicate that particulate GC-A is the main active form of GC in the rat PM, while in guinea pig macrophages the sGC activity dominates. Since the profiles of the PDE activities in rat and guinea pig PM are also different, we conclude that the mechanisms regulating cGMP metabolism in PM are species-specific. Moreover, our results suggest that targets for cGMP other than PKG1 should be present in PM of both species.
    Źródło:
    Acta Biochimica Polonica; 2003, 50, 3; 837-847
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chromatograficzna analiza związków budujących kwasy nukleinowe
    Chromatographic analysis of nucleic acids constituents
    Autorzy:
    Studzińska, S.
    Rola, R.
    Łobodziński, F.
    Krzemińska, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/172180.pdf
    Data publikacji:
    2016
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    nukleozydy
    nukleotydy
    oligonukleotydy
    chromatografia cieczowa
    czułość
    selektywność
    nucleosides
    nucleotides
    oligonucleotides
    liquid chromatography
    sensitivity
    selectivity
    Opis:
    Understanding the characteristics, role and structure of nucleic acids allowed to answer questions about the disease processes. Today, nucleic acids and their constituents are tools, which are used by molecular biology in medicine and biotechnology. Antisense and gene therapy are intensively developing methods for possible treating or preventing disease. They use short fragments of DNA or RNA - oligonucleotides to silence the genes expression. They are not the only ones that allow analytical chemists to obtain information about the state of our body. Determination of modified nucleoside allows detection of cancer, while analysis of nucleotides allows the estimation of strengthening the immune system. There is a great need of sensitive, selective and precise methods of separation of nucleosides, nucleotides and oligonucleotides and their qualitative and quantitative analysis. Consequently liquid chromatography (LC) is the most commonly used for analysis of nucleic acid constituents. The most widely used modes of LC include Ion Exchange Chromatography (IEC) and Reversed Phase High Performance Liquid Chromatography (RP HPLC). Both techniques have their advantages and disadvantages in the analysis of nucleosides, nucleotides and oligonucleotides. In the case of IEC it is necessary to use high concentrations of the salt in the mobile phase or concentration gradients, which considerably limits the possibility of using MS detection. RP HPLC can be coupled with MS detection but only when volatile salts are mobile phase components. On the other hand there is a significant problem is the lack of sufficient selectivity for the most polar nucleosides and nucleotides. RP HPLC MS is still most often used in the determination of nucleosides and nucleotides, due to its high sensitivity and a comprehensive qualitative analysis. Another system used for the HPLC analysis of oligonucleotides is Ion Pair Reversed Phase High Performance Liquid Chromatography (IP RP HPLC). These compounds can not be analyzed by RP HPLC due to their high polarity. The advantage of IP RP HPLC is selectivity, achieved by a suitable choice of mobile phase composition and the possibility of using MS. A disadvantage of IP RP HPLC in the analysis of oligonucleotides is however lower sensitivity compared to RP HPLC. During the last few years Hydrophilic Interaction Liquid Chromatography (HILIC) was applied for the separation of mixtures of nucleosides, nucleotides, oligonucleotides extracted from a biological or food samples. The presented results demonstrate the usefulness of this method, however, the resolving power is limited due to the asymmetric peak shape. On the other hand proper selection of the mobile and stationary phase can lead to a high selectivity in the analysis of the most polar nucleosides, nucleotides and oligonucleotides, which can not be separated by RP HPLC.
    Źródło:
    Wiadomości Chemiczne; 2016, 70, 9-10; 633-656
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Rola sygnalizacji purynergicznej i cytokin w indukcji procesów zapalnych w udarze niedokrwiennym mózgu
    Role of purinergic signalling and cytokines in the ischaemic stroke
    Autorzy:
    Cieślak, Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/1057753.pdf
    Data publikacji:
    2012
    Wydawca:
    Medical Communications
    Tematy:
    nukleotydy
    nukleozydy
    cytokiny
    receptory purynergiczne
    udar niedokrwienny mózgu
    nucleotides
    nucleosides
    cytokines
    purinergic receptors
    ischaemic stroke
    Opis:
    Inflammation plays an important role in the aetiology of various diseases of the central nervous system including the stroke. Accumulating evidence indicates that inflammation in the central nervous system is controlled by purinergic signalling. The mediators of purinergic signalling are extracellular nucleotides (e.g. ATP, ADP, UTP and UDP) and adenosine that act via activation of P2 and P1 purinergic receptors, respectively. The activation of P2 and P1 receptors is regulated by the enzymes ectonucleotidases that hydrolyse either extracellular nucleotides or adenosine. This review focuses on the role of purinergic signalling in the ischaemic stroke. We and others have demonstrated the presence of nucleotides and adenosine in the cerebrospinal fluid. We have also shown that the concentration of ATP and other nucleotides is increased in cerebrospinal fluid of patients with ischaemic stroke. Evidence suggests that the activation of P2 and P1 recep-tors have an opposite role in the ischaemic stroke, i.e. while the nucleoside adenosine exert neuroprotective effects, nucleotides generally promote the proinflammatory and apoptotic responses. P2X7, P2Y2, P2Y6, P2Y11 and P2Y12 are proposed to be involved in the central nervous system inflammation as they are expressed in the brain and their activation is known to control the key inflammatory processes such as release of inflammatory mediators (e.g. cytokines, NO), migration of leukocytes, phagocytosis, apoptosis and thrombosis. The activation of P2 receptors can also increase the release of excitatory neurotransmitters that further exacerbate the inflammatory response. Three cytokines whose release is controlled by P2 receptors have a major role in the ischaemic stroke, namely tumour necrosis factor alpha (TNF-α), interleukin 1 (IL-1) and interleukin 6 (IL-6). By promoting inflammation and thrombosis, these proinflammatory cytokines contribute to the increase in lesion size and thus functional impairment of the affected tissue. Cytokines as well as extracellular nucleotides are involved in leukocyte migration to lesions. By their adherence to endothelium, leukocytes impair cerebral blood circulation and thus exacerbate damage to the brain. The hydrolysis of nucleotides to adenosine by the ectonucleotidases leads to deactivation of proinflammatory responses. Similar effect can also be obtained with P2X7 and IL-1 receptor antagonists that are presently under clinical development and investigation.
    Wyniki badań opublikowanych w ostatnich latach wskazują, że indukcja stanów zapalnych w ośrodkowym układzie nerwowym może stanowić podstawę patofizjologiczną wielu chorób, w tym udaru niedokrwiennego mózgu. Istotną rolę w tych procesach przypisuje się sygnalizacji purynergicznej i cytokinom. Receptory purynergiczne P1 i P2 oraz enzymy uczestniczące w degradacji nukleotydów są szeroko rozpowszechnione na komórkach ośrodkowego układu nerwowego. Puryny i pirymidyny wykazują dwojakie działanie w udarze niedokrwiennym mózgu: pozytywne (neuroprotekcyjne) nukleozydów oraz negatywne (prozapalne i proapoptotyczne) nukleotydów. W przebiegu udaru niedokrwiennego mózgu udowodniono udział w indukcji procesów zapalnych trzech cytokin: czynnika martwicy nowotworów α (TNF-α), interleukiny 1 (IL-1) i interleukiny 6 (IL-6). Cytokiny prozapalne wywołują procesy zapalne i prozakrzepowe, przez co zwiększają obszar zawału, a w konsekwencji stopień deficytu neurologicznego. Cytokiny i ATP sprzyjają migracji leukocytów do miejsca niedokrwienia mózgu, natomiast adenozyna działa przeciwstawnie. Leukocyty, przylegając do śródbłonka, upośledzają przepływ mózgowy krwi, w wyniku czego nasilają uszkodzenie tkanki nerwowej. Na uwalnianie cytokin prozapalnych, głównie interleukiny 1β, wpływa aktywacja receptora P2X7. Przypuszcza się, że w procesach zapalnych ośrodkowego układu nerwowego mogą uczestniczyć także receptory: P2Y2, P2Y6, P2Y11, P2Y12. Wydaje się, że degradacja nukleotydów z powstaniem adenozyny może być skutecznym sposobem obniżenia stężenia w przestrzeni pozakomórkowej nukleotydów, jak również cytokin prozapalnych i wygaszania procesów zapalnych. Inną metodą osłabienia intensywności procesów zapalnych jest zastosowanie antagonistów receptora P2X7 oraz inhibitora receptora IL-1 (IL-1Ra). Obecnie prowadzone są badania zarówno nad potencjalnymi antagonistami receptora P2X7, jak i inhibitorem receptora IL-1 (IL-1Ra).
    Źródło:
    Aktualności Neurologiczne; 2012, 12, 4; 205-214
    1641-9227
    2451-0696
    Pojawia się w:
    Aktualności Neurologiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of Organophosphorus Compounds. 1. Application of Iodine-Azide Reaction for Detection of Thiophosphoorganic Compounds in Thin-Layer Chromatography
    Autorzy:
    Kotyński, Andrzej
    Kudzin, Zbigniew H
    Ciesielski, Witold
    Powiązania:
    https://bibliotekanauki.pl/articles/896207.pdf
    Data publikacji:
    2004
    Wydawca:
    Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
    Tematy:
    induced iodine-azide reaction
    organophosphorus inductors
    phosphorothioates
    sugar phosphorothioates
    thiophosphoryl nucleotides
    microdetermination of thiophophoryl inductors
    detection
    TLC
    Opis:
    Wydrukowano z dostarczonych Wydawnictwu UŁ gotowych materiałów
    Źródło:
    Acta Universitatis Lodziensis. Folia Chimica; 2004, 13
    0208-6182
    Pojawia się w:
    Acta Universitatis Lodziensis. Folia Chimica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Xanthine, xanthosine and its nucleotides: solution structures of neutral and ionic forms, and relevance to substrate properties in various enzyme systems and metabolic pathways.
    Autorzy:
    Kulikowska, Ewa
    Kierdaszuk, Borys
    Shugar, David
    Powiązania:
    https://bibliotekanauki.pl/articles/1043286.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    enzyme reactions
    prototropic tautomerism
    xanthine
    caffeine biosynthesis
    metabolic pathways
    G proteins
    base pairing
    xanthosine
    acid/base properties
    nucleotides
    Opis:
    The 6-oxopurine xanthine (Xan, neutral form 2,6-diketopurine) differs from the corresponding 6-oxopurines guanine (Gua) and hypoxanthine (Hyp) in that, at physiological pH, it consists of a ≈ 1:1 equilibrium mixture of the neutral and monoanionic forms, the latter due to ionization of N(3)-H, in striking contrast to dissociation of the N(1)-H in both Gua and Hyp at higher pH. In xanthosine (Xao) and its nucleotides the xanthine ring is predominantly, or exclusively, a similar monoanion at physiological pH. The foregoing has, somewhat surprisingly, been widely overlooked in studies on the properties of these compounds in various enzyme systems and metabolic pathways, including, amongst others, xanthine oxidase, purine phosphoribosyltransferases, IMP dehydrogenases, purine nucleoside phosphorylases, nucleoside hydrolases, the enzymes involved in the biosynthesis of caffeine, the development of xanthine nucleotide-directed G proteins, the pharmacological properties of alkylxanthines. We here review the acid/base properties of xanthine, its nucleosides and nucleotides, their N-alkyl derivatives and other analogues, and their relevance to studies on the foregoing. Included also is a survey of the pH-dependent helical forms of polyxanthylic acid, poly(X), its ability to form helical complexes with a broad range of other synthetic homopolynucleotides, the base pairing properties of xanthine in synthetic oligonucleotides, and in damaged DNA, as well as enzymes involved in circumventing the existence of xanthine in natural DNA.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 2; 493-531
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Purine metabolism in the light of aerobic and anaerobic capacity of female boxers
    Autorzy:
    Domaszewska, Katarzyna
    Szewczyk, Piotr
    Kryściak, Jakub
    Michalak, Edyta
    Podgórski, Tomasz
    Powiązania:
    https://bibliotekanauki.pl/articles/1030895.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
    Tematy:
    Acid-Base Balance (ABB)
    Wingate anaerobic test
    anaerobic threshold (AT)
    maximal oxygen uptake
    purine nucleotides
    uric acid
    Opis:
    The aim of the work was to assess the intensity of purine nucleotide degradation during maximum physical exercise. 5 elite female boxers were the subject of the study. Each of them underwent two exercise stress tests in order to evaluate the level of V̊O2peak and the level of anaerobic capacity during a Wingate test. The study involved collecting capillary and venous blood samples at rest and after the exercise test to determine the Acid-Base Balance (ABB), concentration of lactic acid (LA) and purine metabolism nucleotides. The average value of V̊O2peak was 40.92 (SD = 4.087) ml/kg/min, the average anaerobic capacity Ppeak was 7.57 (SD = 0.380) Watt/kg. The workload resulted in significant changes in the level of ABB and LA after both of the exercise stress tests (p < 0.001). Concentrations of hypoxanthine (Hx), xanthine (X) and uric acid (UA) in the blood increased significantly after the Wingate test (p < 0.05). The level of plasma purine nucleotides at rest and after standard exercise may be a useful tool for monitoring the adaptation of energetic processes in different training phases and support the overload diagnosis.
    Źródło:
    Central European Journal of Sport Sciences and Medicine; 2020, 30, 2; 97-106
    2300-9705
    2353-2807
    Pojawia się w:
    Central European Journal of Sport Sciences and Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Wykorzystanie spektrometrii mas do analizy modyfikacji nukleotydów i adduktów DNA
    Application of mass spectrometry methods for analysis of modified nucleotides and DNA adducts
    Autorzy:
    Hanus, J.
    Jelonek, K.
    Pietrowska, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/171867.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Chemiczne
    Tematy:
    kancerogeneza
    diagnostyka molekularna
    spektrometria mas
    nukleotydy
    uszkodzenia DNA
    addukty DNA
    metylacja DNA
    carcinogenesis
    molecular diagnostics
    mass spectrometry
    nucleotides
    DNA damage
    DNA adducts
    DNA methylation
    Opis:
    Chemically modified nucleotides, which are not normally present in genetic material, are called DN A adducts. This type of DN A modifications (damage) is directly related to processes of mutagenesis and carcinogenesis. Elevated levels of DN A adducts present in genetic material reflect exposure of humans to carcinogenic factors and are markers of increased risk of cancer [1]. For this reason different methods useful for quantitative and qualitative analyses of DN A adducts are used in the field of cancer prevention and research (Tab. 1). Enzymatically-catalyzed methylation of cytosine, observed mostly in so called CpG islands, is a frequent endogenous modification of genetic material. Such a DN A methylation is a key factor involved in regulation of gene expression, and methylation status of oncogenes and tumor supressor genes is an important biomarker of carcinogenesis. As such, analytical methods for assessment of DN A methylation are of great importance for molecular diagnostics of cancer. During the last decade significant progress has been made in methods available for quantitative, qualitative and structural analyses of biological molecules. Among intensively developed tools for bioanalyses are methods of mass spectrometry. Spectrometers that are based on two methods of ionization, namely electrospray ionization (ESI ) [30] and matrix-assisted laser desorption-ionization (MALDI ) [48], are particularly suitable for analyses of biological macromolecules: proteins and nucleic acids. Currently available mass spectrometers, together with microscale methods for sample preparation and separation, significantly increased sensitivity and accessible mass range of analyses. New generation of “user-friendly” instruments is developed to bring the techniques directly into the workplaces of biological and clinical investigators. This review demonstrates representative examples of mass spectrometry techniques used for qualitative analyses of nucleotide modifications and adducts present in genetic material of humans. In this field several methods base on spectrometers with electrospray ionization. Generated ions are separated according to their mass-to-charge ratio in an analyzer by electric fields; among different ion analyzers frequently used in this methods are single or triple quadrupole and ion traps (Fig. 1). Among other methods available for assessment of DN A adducts is so called Accelerator Mass Spectrometry (Fig. 2) [41]. The most frequently applied method for the assessment of DN A methylation is based on methylation-specific PCR reaction. Products of such PCR reactions are analyzed using MALDI mass spectrometry [54] (Fig. 3). In summary, new powerful methods of mass spectrometry that made available qualitative analyses of damage and modifications of human genetic material found their important place in modern biological and medical laboratories.
    Źródło:
    Wiadomości Chemiczne; 2011, 65, 3-4; 191-205
    0043-5104
    2300-0295
    Pojawia się w:
    Wiadomości Chemiczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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