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    Wyświetlanie 1-9 z 9
    Tytuł:
    Maillard neoglycans as inhibitors for in vitro adhesion of F4+ enterotoxigenic Escherichia coli to piglet intestinal cells
    Autorzy:
    Sarabia-Sainz, Héctor
    Mata Haro, Verónica
    Sarabia Sainz, José
    Vázquez-Moreno, Luz
    Montfort, Gabriela
    Powiązania:
    https://bibliotekanauki.pl/articles/1038559.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    Albumin glycation
    biorecognition
    anti-adhesion
    E. coli
    Opis:
    Adhesion of enterotoxigenic (ETEC) E. coli to host intestinal cells is mediated by lectin-like fimbriae that bind to specific glycan moieties on the surfaces of enterocytes. To prevent in vitro binding of E. coli F4 fimbriae (F4 ETEC+) to piglet enterocytes, neoglycans were synthesized by the Maillard reaction conjugating lactose (Lac), galacto-oligosaccharides (GOS) or chitin oligosaccharides (Ochit) to porcine serum albumin (PSA). Neoglycans were characterized by SDS-PAGE, intrinsic tryptophan fluorescence and recognition by plant lectins, as well as by F4 ETEC variants. Electrophoretic patterns suggested the binding to PSA of 63, 13 and 2 molecules of Lac, GOS and Ochit, respectively. All neoglycans displayed quenching of tryptophan fluorescence consistent with the degree of glycation estimated by SDS-PAGE. Plant lectins recognized the neoglycans according to their specificity, whereas antigenic variants of F4 ETEC (ab, ac and ad) recognized PSA-Ochit and PSA-Lac with higher affinity than that for GOS. Neoglycans partially hindered the in vitro binding of F4+ ETEC to piglet enterocytes in a dose-dependent manner. The most effective blocking was observed with PSA-Lac that partially inhibited the adhesion of bacteria to enterocytes in a dose dependent manner, as quantified by flow cytometry. Increased production of the cytokines IL-6 and TNF-α was observed in response to F4+ ETEC infection of enterocytes and production was reduced in the presence of PSA-Ochit and PSA-GOS. These results suggest that neoglycans synthesized by the Maillard reaction could be useful in the prophylaxis of diarrhea in piglets.
    Źródło:
    Acta Biochimica Polonica; 2017, 64, 4; 679-686
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Type 1 fimbriae in commensal Escherichia coli derived from healthy humans
    Autorzy:
    Pusz, Paweł
    Bok, Ewa
    Mazurek, Justyna
    Stosik, Michał
    Baldy-Chudzik, Katarzyna
    Powiązania:
    https://bibliotekanauki.pl/articles/1039310.pdf
    Data publikacji:
    2014
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    commensal E. coli
    type 1 fimbriae
    gene expression
    Opis:
    Type 1 fimbriae are one of the most important factors of Escherichia coli adaptation to different niches in the host. Our study indicated that the genetic marker - fimH gene occurred commonly in commensal E. coli derived from healthy humans but expression of the type 1 fimbriae was not observed. Identification of fim structural subunit genes (fimA-fimH) and recombinase fimE and fimB genes showed that many of the strains were carrying an incomplete set of genes and the genes expression study revealed that in strains with complete set of fim genes, the fimC gene, encoding the chaperone protein, was not expressed.
    Źródło:
    Acta Biochimica Polonica; 2014, 61, 2; 389-392
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    CEA-negative glioblastoma and melanoma cells are sensitive to cytosine deaminase/5-fluorocytosine therapy directed by the carcinoembryonic antigen promoter.
    Autorzy:
    Dąbrowska, Anna
    Szary, Jarosław
    Kowalczuk, Małgorzata
    Szala, Stanisław
    Ugorski, Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/1041550.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    CEA promoter
    E. coli cytosine deaminase
    gene-directed enzyme prodrug therapy
    Opis:
    Recent studies have suggested that carcinoembryonic antigen (CEA)-promoter sequences are active only in CEA-positive cells, filing in the criteria for tumor specific targeting of suicide genes. However, the present study on gene therapy of colon cancer and cell-specificity of CEA promoter, provide evidence that CEA-positive and CEA-negative cells transfected with E. coli cytosine deaminase (CD) gene under the control of CEA promotor sequence are sensitive to enzyme/pro-drug therapy with 5-fluorocytosine (5-FC). Individual clones derived from the CEA-negative cell lines: melanoma Hs294T and glioblastoma T98G after transfection with CD differed profoundly in their sensitivity to 5-FC. The IC50 values for several clones of the CEA-negative cells were almost the same as for CEA-positive colon cancer cells. Such 5-FC-sensitive clones derived from the population of CEA-negative cells, present even in small number, because of the very effective bystender effect of this enzyme/pro-drug system can cause severe problems during therapy by efficiently killing surrounding normal cells. Safety is the major issue in gene therapy. Our data suggest that the safety of gene-directed enzyme pro-drug therapy (GDEPT) with CEA promoter driven expression of therapeutic genes is not so obvious as it has originally been claimed.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 3; 723-732
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mutator specificity of Escherichia coli alkB117 allele
    Autorzy:
    Nieminuszczy, Jadwiga
    Janion, Celina
    Grzesiuk, Elżbieta
    Powiązania:
    https://bibliotekanauki.pl/articles/1041261.pdf
    Data publikacji:
    2006
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    lacZ → Lac+ reversion
    mutational specificity
    E. coli
    MMS
    alkB117
    Opis:
    The Escherichia coli AlkB protein encoded by alkB gene was recently found to repair cytotoxic DNA lesions 1-methyladenine (1-meA) and 3-methylcytosine (3-meC) by using a novel iron-catalysed oxidative demethylation mechanism that protects the cell from the toxic effects of methylating agents. Mutation in alkB results in increased sensitivity to MMS and elevated level of MMS-induced mutations. The aim of this study was to analyse the mutational specificity of alkB117 in a system developed by J.H. Miller involving two sets of E. coli lacZ mutants, CC101-106 allowing the identification of base pair substitutions, and CC107-CC111 indicating frameshift mutations. Of the six possible base substitutions, the presence of alkB117 allele led to an increased level of GC→AT transitions and GC→TA and AT→TA transversions. After MMS treatment the level of GC→AT transitions increased the most, 22-fold. Among frameshift mutations, the most numerous were -2CG, -1G, and -1A deletions and +1G insertion. MMS treatment appreciably increased all of the above types of frameshifts, with additional appearance of the +1A insertion.
    Źródło:
    Acta Biochimica Polonica; 2006, 53, 2; 425-428
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design of small molecule inhibitors of type III secretion system ATPase EscN from enteropathogenic Escherichia coli
    Autorzy:
    Bzdzion, Lukasz
    Krezel, Hanna
    Wrzeszcz, Karol
    Grzegorek, Irmina
    Nowinska, Katarzyna
    Chodaczek, Grzegorz
    Swietnicki, Wieslaw
    Powiązania:
    https://bibliotekanauki.pl/articles/1038684.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    Escherichia coli (E. coli)
    type III secretion system (T3SS)
    enzyme inhibitor
    small molecule
    Opis:
    Enteropathogenic E. coli (EPEC) is a human pathogen using type III secretion system for delivery of proteins directly into the human host. The system contains a single ATPase, EscN, which is essential for uncoupling of proteins from their complexes with chaperones before the delivery. The structure of EscN ATPase (PDB code: 2obm) was used to screen computationally for small molecule inhibitors blocking its active site. Two lead candidates were examined but only one, Compound 54, was selected for further optimization. After extended QSAR optimization, two derivatives were found to be competitive inhibitors of EscN capable of blocking ATPase activity with a Ki below 50 µM. One candidate, WEN05-03, with a Ki=16±2 µM, was also minimally toxic to mammalian cells as determined by other assays. In the cell infection model of HeLa cells with EPEC, Compound WEN05-03 completely blocked actin cluster formation at 100 µM concentration, when analyzed by confocal microscopy. The second best inhibitor of EscN ATPase activity was WEN04-34 with a Ki=46±2 µM. However, the compound was highly toxic to the BALB/3T3 cell line. In summary, the work identifies a compound blocking bacterial ATPase in its active site without causing cellular toxicity to the host cells. It is the first report showing feasibility of using bacterial virulence system ATPase as a target for safe, non-toxic compounds and offering a proof-of-concept for non-antibiotic alternatives.
    Źródło:
    Acta Biochimica Polonica; 2017, 64, 1; 49-63
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of SOS-induced Pol II, Pol IV, and Pol V DNA polymerases on UV-induced mutagenesis and MFD repair in Escherichia coli cells.
    Autorzy:
    Wrzesiński, Michał
    Nowosielska, Anetta
    Nieminuszczy, Jadwiga
    Grzesiuk, Elżbieta
    Powiązania:
    https://bibliotekanauki.pl/articles/1041471.pdf
    Data publikacji:
    2005
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    MFD
    polB
    UV induced mutagenesis
    E. coli
    dinB
    mutD5
    umuDC
    Opis:
    Irradiation of organisms with UV light produces genotoxic and mutagenic lesions in DNA. Replication through these lesions (translesion DNA synthesis, TSL) in Escherichia coli requires polymerase V (Pol V) and polymerase III (Pol III) holoenzyme. However, some evidence indicates that in the absence of Pol V, and with Pol III inactivated in its proofreading activity by the mutD5 mutation, efficient TSL takes place. The aim of this work was to estimate the involvement of SOS-inducible DNA polymerases, Pol II, Pol IV and Pol V, in UV mutagenesis and in mutation frequency decline (MFD), a mechanism of repair of UV-induced damage to DNA under conditions of arrested protein synthesis. Using the argE3→Arg+ reversion to prototrophy system in E. coli AB1157, we found that the umuDC-encoded Pol V is the only SOS-inducible polymerase required for UV mutagenesis, since in its absence the level of Arg+ revertants is extremely low and independent of Pol II and/or Pol IV. The low level of UV-induced Arg+ revertants observed in the AB1157mutD5ΔumuDC strain indicates that under conditions of disturbed proofreading activity of Pol III and lack of Pol V, UV-induced lesions are bypassed without inducing mutations. The presented results also indicate that Pol V may provide substrates for MFD repair; moreover, we suggest that only those DNA lesions which result from umuDC-directed UV mutagenesis are subject to MFD repair.
    Źródło:
    Acta Biochimica Polonica; 2005, 52, 1; 139-147
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Bacterial recognition of thermal glycation products derived from porcine serum albumin with lactose
    Autorzy:
    Sarabia-Sainz, Andre-i
    Ramos-Clamont, Gabriela
    Winzerling, Joy
    Vázquez-Moreno, Luz
    Powiązania:
    https://bibliotekanauki.pl/articles/1039957.pdf
    Data publikacji:
    2011
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    neoglycans
    bacterial recognition
    E. coli K88 adhesion
    glycation of serum albumin
    Opis:
    Recently, glyco-therapy is proposed to prevent the interaction of bacterial lectins with host ligands (glycoconjugates). This interaction represents the first step in infection. Neoglycans referred to as PSA-Lac (PSA-Glu (β1-4) Gal) were obtained by conjugation of porcine serum albumin (PSA) with lactose at 80 °C, 100 °C and 120 ºC. Characterization studies of the products showed that PSA could contain 1, 38 or 41 added lactoses, depending on the reaction temperature. These neoglycans were approximately 10 times more glycated than PSA-Lac obtained in previous work. Lactose conjugation occurred only at lysines and PSA-Lac contained terminal galactoses as confirmed by Ricinus communis lectin recognition. Furthermore, Escherichia coli K88+, K88ab, K88ac and K88ad adhesins showed affinity toward all PSA-Lac neoglycans, and the most effective was the PSA-Lac obtained after 100 ºC treatment. In vitro, this neoglycan partially inhibited the adhesion of E. coli K88+ to piglet mucin (its natural ligand). These results provide support for the hypothesis that glycated proteins can be used as an alternative for bioactive compounds for disease prevention.
    Źródło:
    Acta Biochimica Polonica; 2011, 58, 1; 95-100
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Spontaneous mutagenesis in exponentially growing and stationary-phase, umuDC-proficient and -deficient, Escherichia coli dnaQ49.
    Autorzy:
    Nowosielska, Anetta
    Nieminuszczy, Jadwiga
    Grzesiuk, Elżbieta
    Powiązania:
    https://bibliotekanauki.pl/articles/1041546.pdf
    Data publikacji:
    2004
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    dnaQ49
    argE3→Arg+ revertants
    E. coli
    Pol V
    spontaneous mutagenesis
    stationary-phase mutations
    Opis:
    Spontaneous mutations arise not only in exponentially growing bacteria but also in non-dividing or slowly dividing stationary-phase cells. In the latter case mutations are called adaptive or stationary-phase mutations. High spontaneous mutability has been observed in temperature sensitive Escherichia coli dnaQ49 strain deficient in 3'→5' proofreading activity assured by the ε subunit of the main replicative polymerase, Pol III. The aim of this study was to evaluate the effects of the dnaQ49 mutation and deletion of the umuDC operon encoding polymerase V (Pol V) on spontaneous mutagenesis in growing and stationary-phase E. coli cells. Using the argE3OC →Arg+ reversion system in the AB1157 strain, we found that the level of growth-dependent and stationary-phase Arg+ revertants was significantly increased in the dnaQ49 mutant at the non-permissive temperature of 37°C. At this temperature, in contrast to cultures grown at 28°C, SOS functions were dramatically increased. Deletion of the umuDC operon in the dnaQ49 strain led to a 10-fold decrease in the level of Arg+ revertants in cultures grown at 37°C and only to a 2-fold decrease in cultures grown at 28°C. Furthermore, in stationary-phase cultures Pol V influenced spontaneous mutagenesis to a much lesser extent than in growing cultures. Our results indicate that the level of Pol III desintegration, dependent on the temperature of incubation, is more critical for spontaneous mutagenesis in stationary-phase dnaQ49 cells than the presence or absence of Pol V.
    Źródło:
    Acta Biochimica Polonica; 2004, 51, 3; 683-692
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mismatch dependent uracil/thymine-DNA glycosylases excise exocyclic hydroxyethano and hydroxypropano cytosine adducts.
    Autorzy:
    Borys-Brzywczy, Ewa
    Arczewska, Katarzyna
    Saparbaev, Murat
    Hardeland, Ulrike
    Schär, Primo
    Kuśmierek, Jarosław
    Powiązania:
    https://bibliotekanauki.pl/articles/1041473.pdf
    Data publikacji:
    2005
    Wydawca:
    Polskie Towarzystwo Biochemiczne
    Tematy:
    base excision repair
    E. coli mismatch uracil-DNA glycosylase
    exocyclic cytosine adducts
    human thymine-DNA glycosylase
    S. pombe Thp1p glycosylase
    Opis:
    Exocyclic adducts of DNA bases, such as etheno- and hydroxyalkano- ones, are generated by a variety of bifunctional agents, including endogenously formed products of lipid peroxidation. In this work we selectively modified cytosines in the 5'-d(TTT TTT CTT TTT CTT TTT CTT TTT T)-3' oligonucleotide using: chloroacetaldehyde to obtain 3,N4-α-hydroxyethano- (HEC) and 3,N4-etheno- (εC), acrolein to obtain 3,N4-α-hydroxypropano- (HPC) and crotonaldehyde to obtain 3,N4-α-hydroxy-γ-methylpropano- (mHPC) adducts of cytosine. The studied adducts are alkali-labile which results in oligonucleotide strain breaks at the sites of modification upon strong base treatment. The oligonucleotides carrying adducted cytosines were studied as substrates of Escherichia coli Mug, human TDG and fission yeast Thp1p glycosylases. All the adducts studied are excised by bacterial Mug although with various efficiency: εC >HEC >HPC >mHPC. The yeast enzyme excises efficiently εC ł HEC >HPC, whereas the human enzyme excises only εC. The pH-dependence curves of excision of εC, HEC and HPC by Mug are bell shaped and the most efficient excision of adducts occurs within the pH range of 8.6-9.6. The observed increase of excision of HEC and HPC above pH 7.2 can be explained by deprotonation of these adducts, which are high pKa compounds and exist in a protonated form at neutrality. On the other hand, since εC is in a neutral form in the pH range studied, we postulate an involvement of an additional catalytic factor. We hypothesize that the enzyme structure undergoes a pH-induced rearrangement allowing the participation of Lys68 of Mug in catalysis via a hydrogen bond interaction of its ε-amino group with N4 of the cytosine exocyclic adducts.
    Źródło:
    Acta Biochimica Polonica; 2005, 52, 1; 149-165
    0001-527X
    Pojawia się w:
    Acta Biochimica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-9 z 9

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