Wyniki wyszukiwania

1

Inhibitors of DNA polymerase beta inhibit base excision repair

100%

Yoshida S., Ogawa A.

Polish Journal of Environmental Studies

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1999

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tom 08

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nr 5

2

An unexpected effect of 2-chloro-2'deoxyadenosine on DNA synthesis in EHEB cells

88%

Cardoen S., Bontemps F., Van Den Neste E., Van Den Berghe G.

Cellular and Molecular Biology Letters

|

1999

|

tom 04

|

nr 3

3

Caffeine-induced premature chromosome condesation [PCC] in the root meristem cells of Vicia faba

88%

Maszewski J., Rybaczek D.

Cellular and Molecular Biology Letters

|

2002

|

tom 07

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nr Suppl.

4

Day-to-night activity of bacteria in the surface microlayer eutrophic lake

75%

Walczak M.

Polish Journal of Ecology

|

2008

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tom 56

|

nr 3

379-389

This study examined changes of bacteria numbers in the surface microlayer (SM) and subsurface water (SW) of a lake during a day- and night-time. The research also addresses the synthesis of DNA and cell protein as well as the activity of cellular dehydrogenases depending on time of the day. Results demonstrated that in spring and summer the numbers of bacteria (per cm3 ) in the SM was significantly greater during night-time than day-time (average: May, daytime – 30.058 × 10⁶, night-time – 71.343 × 10⁶; July, day-time – 10.801 × 10⁶, night-time – 40.353 × 10⁶). In October, numbers of bacteria in dayand night-time were not statistically different (respectively: 5.841 × 10⁶ and 3.664 × 10⁶). Results indicated also that the rate of DNA synthesis by SM bacteria was much higher in the night-time (average: May – 2.049 × 10⁻⁶ pg h⁻¹ cell⁻¹; July – 1.363 × 10⁻⁶ pg h⁻¹ cell⁻¹), than in the day-time (average: May – 0.7263 × 10⁻⁶ pg h⁻¹ cell⁻¹; July – 0.3404 ×10⁻⁶ pg h⁻¹ cell⁻¹). In contrast, in October the values of DNA synthesis by SM bacteria were higher in night-time. These changes are significantly smaller in SW at a depth of several dozen centimetres. However, no significant impact was observed of a time of the day on the activity of protein synthesis and activity of cellular dehydrogenases by bacteria inhabiting SM and SW.

5

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The effect of antagonist of receptors for gastrin, cholecystokinin and bombesin on growth of gastroduodenal mucosa and pancreas

75%

Dembinski A., Warzecha Z., Konturek S. J., Banas M., Cai R.-Z., Schally A. V.

Journal of Physiology and Pharmacology

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1991

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tom 42

|

nr 3

The effects of gastrin, cholecystokinin (CCK) and bombesin on the DNA synthesis, as a biochemical indicator of trophic action in the gastroduodenal mucosa and the pancreas, have been examined in rats fasted for 48 h and in rats refed for 16 h with or without administration of specific receptor antagonists for bombesin, gastrin and CCK. Bombesin and gastrin administered three times daily for 48 h in fasted rats significantly increased the rate of DNA synthesis as measured by the incorporation of [³H] thymidine into DNA in each tissue tested. CCK significantly increased DNA synthesis in the duodenal mucosa and pancreatic tissue, but not in the gastric mucosa. The stimulation of DNA synthesis induced by bombesin in the gastroduodenal mucosa and pancreas was abolished by bombesin/GRP receptor antagonist, RC-3095. RC-3095 did not affect DNA synthesis stimulated by gastrin and CCK in these tissues. L-365,260, a receptor antagonist for gastrin suppressed the DNA synthesis induced by gastrin but not by CCK or bombesin in the gastrointestinal mucosa and pancreas. L-364,718, a specific antagonist for CCK receptors was effective only against CCK stimulated duodenal mucosa and pancreatic growth. Refeeding of 48 h fasting rats strongly enhanced the DNA synthesis in all tissues tested, and this effect was significantly reduced in the gastroduodenal mucosa by blocking only gastrin receptors (with L-365, 260) and that in the duodenal mucosa and the pancreas by antagonizing of CCK receptors (with L-364, 718). Antagonism of bombesin receptors (with RC-3095) did not significantly affect the stimulation of DNA synthesis induced by refeeding in all tissues tested. This study indicates that the stimulation of DNA synthesis can be achieved by exogenous gastrin, CCK and bombesin acting through separate receptors, but that only gastrin and CCK play the major role in the postprandial stimulation of the growth of gastroduodenal mucosa and pancreatic tissue.

6

Cytophotometric estimation of nucleic acids and computer image analysis of the nuclei in the cell cycle phases

75%

Krygier-Stojalowska A., Joachimiak H., Gapski Z.

Folia Histochemica et Cytobiologica

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1984

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tom 22

|

nr 3-4

7

Influence of central and peripheral administration of pancreatic polypeptide on gastric mucosa growth

75%

Dembinski A., Warzecha Z., Ceranowicz P., Pawlik M., Dembinski M., Kabat K., Konturek S. J., Kownacki P., Hladki W., Pawlik W. W.

Journal of Physiology and Pharmacology

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2004

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tom 55

|

nr 1,2

Previous studies have shown that pancreatic polypeptide (PP) inhibits exocrine pancreatic secretion. The aim of present study was to determine the influence of PP administration on gastric growth and blood flow. Methods: Study was performed on regularly fed, fasted or fasted and subsequently refed rats. Rats were treated with saline (intraperitoneally - i.p.), caerulein (0.24 nmol/kg/dose, i.p.), pentagastrin (0.38 µmol/kg/dose, i.p.) or PP (5 nmol/kg/dose, i.p. or 10 pmol/dose intracerebroventricularly - i.c.v.). Saline, caerulein, pentagastrin and PP were administered alone or in combination, 3 times daily during last 48 h of experiment. Results: Treatment with pentagastrin increased gastric mucosa weight, mucosal DNA synthesis and gastric blood flow in all group tested. Intraperitoneal and i.c.v administration of PP alone reduced mucosal DNA synthesis in regularly fed and refed animals, and decreased gastric blood flow in refed animals. Combination of PP i.p. or i.c.v plus pentagastrin significantly reduced the pentagastrin-evoked increase in gastric mucosa weight, gastric DNA synthesis and gastric blood flow in fasted animals, as well as regularly fed animals. In refed animals, influence of PP administration on the pentagastrin-evoked increase in gastric mucosa weight was weak and statistically insignificant, but still i.p or i.c.v administration of PP significantly reduced gastric blood flow and mucosal DNA synthesis in this group of animals. Administration of caerulein caused weak, but significant increase in gastric DNA synthesis, gastric mucosa weight and gastric blood flow in fasted rats. In regularly fed animals, caerulein significantly increased only gastric DNA synthesis and gastric blood flow. In fasted animals with subsequent refeeding, caerulein was without effect on parameters tested in the stomach. Neither i.p. nor i.c.v administration of PP affected the caerulein-evoked effects in the stomach. Conclusions: Peripheral and central administration of PP inhibits food- and pentagastrin-stimulated growth of gastric mucosa. Similar effects of low central doses of PP as the high peripheral doses of PP suggests a crucial role of the central nervous system in the inhibitory effect of PP on gastric mucosa growth.

8

Properties of mitochondrial DNA polymerase in mitochondrial DNA synthesis in yeast

75%

Biswas T. K., Sengupta P., Green R., Hakim P., Biswas B., Sen S.

Acta Biochimica Polonica

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1995

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tom 42

|

nr 3

Mitochondrial DNA polymerase from Saccharomyces cerevisiae, purified 3500 fold, was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into three polypeptides. The major 150 kDa polypeptide was probably the catalytic subunit of the mitochondrial (mt) DNA polymerase and the other two polypeptides could be either proteolytic cleavage products of the polymerase, other subunits of the enzyme or protein contaminants. The mtDNA polymerase preferred an A+T-rich DNA template and did not require any RNA primer for DNA synthesis, at least under in vitro reaction conditions. It showed higher processivity on a double-stranded linear DNA template than on a single-stranded circular DNA template, and was capable of synthesizing at least about 1200 nucleotide primer-extended products without any major pause on a double-stranded DNA template.

9

Cell cycle checkpoints - molecular background

75%

Grzelakowska-Sztabert B.

Folia Morphologica

|

2004

|

tom 63

|

nr 1

Cell cycle checkpoints are the surveillance mechanisms monitoring both the fidelity and accuracy of DNA replication and the segregation of chromosomes. By delaying progression through the cell cycle, checkpoints provide more time for repair before the critical phases of DNA replication and ensure the proper segregation of chromosomes during mitosis. The paper provides basic information about the molecular mechanisms operating in various cell cycle checkpoints activated by DNA damage or disturbances in mitotic spindle assembly.

10

Induction of ornithine decarboxylase in normal and protein kinase C - depleted human colon carcinoma cells

75%

Ostrowski J., Szczepiorkowski Z., Trzeciak L., Rochowska M., Skurzak H., Butruk E.

Journal of Physiology and Pharmacology

|

1992

|

tom 43

|

nr 4

To examine the role of protein kinase С (PKC) in induction of human colon adenocarcinoma cell line, DETA/W, by polypeptide growth- promoting factors, ornithine decarboxylase activity (ODC) and DNA synthesis were determined in cells depleted of PKC. PKC depletion was achieved by prolonged cultivation (more than 30 passages) with 10⁻⁶ M phorbol 12-myristate 13-acelate. Lack of PKC in studied cells was proved by measurements of PKC activity and immunoreactivity. Although ODC activities and DNA syntheses in PKC-depleted cells were decreased by about 40-50% compared to normal DETA/W cells, the percentage increase of these mitogen-responsive reactions was quantitatively similar in both cell sublines. These results raise the possibility that not all of the biological responses to growth factors are connected with the activation of calcium-dependent PKC.

11

Comparison of repair activity in different genomic regions

75%

Chakalova L., Russev G.

Acta Biochimica Polonica

|

1998

|

tom 45

|

nr 1

We have developed a quantitative technique to determine repair activity at defined genomic regions. Cells were treated with hydroxyurea to inhibit the replicative DNA synthesis and were incubated with 5-bromodeoxyuridine (BrdUrd) to label the regions undergoing repair. In the course of the labelling, the regions that were more actively repaired would incorporate more BrdUrd than the regions that were less actively repaired. Thus the kinetics of BrdUrd incorporation in the different sequences would reflect the kinetics of reparation of the respective regions. The total BrdUrd-containing, repaired DNA was isolated by immunoprecipitation with anti-BrdUrd antibody, and after controlled sonication, it was used as a template in quantitative PCR in which the amount of the product was directly proportional to the amount of template. This approach was used to address the question whether DNA repair after UV irradiation occurs in an uniformly random manner, or with preferences for certain regions. We found that, in Ehrlich ascites tumor cells, the repair efficiency was higher at the 5' end of the mouse β-globin domain than in the rest of the domain.

12

Gemcitabine affects the detection of deoxyribonucleotides with a DNA polymerase elongation assay

75%

Van Moorsel C. J. A., Smid K., Pinedo H. M., Peters G. J.

Cellular and Molecular Biology Letters

|

1999

|

tom 04

|

nr 3

13

Involvement of the essential yeast DNA polymerases in induced gene conversion

75%

Halas A., Ciesielski A., Zuk J.

Acta Biochimica Polonica

|

1999

|

tom 46

|

nr 4

In the yeast Saccharomyces cerevisiae three different DNA polymerases α, δ and ε are involved in DNA replication. DNA polymerase α is responsible for initiation of DNA synthesis and polymerases δ and ε are required for elongation of DNA strand during replication. DNA polymerases δ and ε are also involved in DNA repair. In this work we studied the role of these three DNA polymerases in the process of recombinational synthesis. Using thermo-sensitive heteroallelic mutants in genes encoding DNA polymerases we studied their role in the process of induced gene conversion. Mutant strains were treated with mutagens, incubated under permissive or restrictive conditions and the numbers of convertants obtained were compared. A very high difference in the number of convertants between restrictive and permissive conditions was observed for polymerases α and δ, which suggests that these two polymerases play an important role in DNA synthesis during mitotic gene conversion. Marginal dependence of gene conversion on the activity of polymerase ε indicates that this DNA polymerase may be involved in this process but rather as an auxiliary enzyme.

14

Incorporation of nitrogen isotope 15N into liver DNA during avian embryogenesis. A new approach for measuring the rate of DNA synthesis

63%

Chwalibog A., Metges C. C., Sawosz Chwalibog E., Grodzik M., Niemiec T.

Journal of Animal and Feed Sciences

|

2010

|

tom 19

|

nr 2

269-276

The objective of this experiment was to test the possibilities of measuring the rate of DNA synthesis in chicken embryos by applying a simple 15N tracer technique. We hypothesized that the rate of 15N incorporation into liver DNA depends on the type of labelled substance, reflecting precursor availability to provide substrates for nucleotide synthesis. Fertilized eggs were divided into 4 groups (4 × 15): control – not treated, and treated with 15N labeled glycine, ammonium chloride, or sodium nitrate. 15N labeled solutions were given in ovo by injection into albumen. After 20 days of incubation, the labeled substances had no effect on embryo development or morphology. Hepatic DNA was purified and 15N abundance was measured by isotope ratio mass spectrometry. There was significant enrichment of 15N in DNA from the glycine and ammonium chloride groups. We conclude that this simple technique of injecting 15N tracers into incubating eggs can be used to estimate the rate of DNA synthesis.

15

The effects of antagonists of receptors for gastrin, cholecystokinin and bombesin on growth of gastroduodenal mucosa and pancreas

63%

Dembinski A., Warzecha Z., Konturek S. J., Zhi Cai R., Schally A. V.

Journal of Physiology and Pharmacology

|

1991

|

tom 42

|

nr 2

The effects of gastrin, cholecystojdnin (CCK) and bombesin on the DNA synthesis, as a biochemical indicator of trophic action in the gastroduodenal mucosa and the pancreas have been examined in rats fasted for 48 h and in rats refed for 16 h with or without administration of specific receptor antagonists for bombesin, gastrin and CCK. Bombesin and gastrin administered three times daily for 48 h in fasted rats significantly increased the rate of DNA synthesis as measured by the incorporation of [³H] thymidine into DNA in each tissue tested. CCK significantly increased DNA synthesis in the duodenal mucosa and pancreatic tissue, but not in the gastric mucosa. The stimulation of DNA synthesis induced by bombesin in the gastroduodenal mucosa and pancreas was abolished by bombesin/GRP receptor antagonist, RC-3095. RC-3095 did not affect DNA synthesis stimulated by gastrin and CCK in these tissues. L-365,260, a receptor antagonist for gastrin suppressed the DNA synthesis induced by gastrin but not by CCK or bombesin in the gastrointestinal mucosa and pancreas. L-364, 718 a specific antagonist for CCK receptors was effective only against CCK stimulated duodenal mucosa and pancreatic growth. Refeeding of 48 h fasting rats strongly enhanced the DNA synthesis in all tissues tested, and this effect was significantly reduced in the gastroduodenal mucosa by blocking only gastrin receptors (with L-365, 260) and that in the duodenal mucosa and the pancreas by antagonizing of CCK receptors (with L-364, 718). Antagonism of bombesin receptors (with RC-3095) did not significantly affect the stimulation of DNA synthesis induced by refeeding in all tissues tested. This study indicates that the stimulation of DNA synthesis can be achieved by exogenous gastrin, CCK and bombesin acting through separate receptor but that only gastrin and CCK play the major role in the postprandial stimulation of the growth of gastroduodenal mucosa and pancreatic tissue.

16

Cellular and regulatory basis of early floral organ growth

63%

Sablowski R.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2013

|

tom 94

|

nr 3

17

Pretreatment with low doses of acenocoumarol inhibits the development of acute ischemia/reperfusion-induced pancreatitis

63%

Warzecha Z., Sendur P., Ceranowicz P., Dembinski M., Cieszkowski J., Kusnierz-Cabala B., Tomaszewska R., Dembinski A.

Journal of Physiology and Pharmacology

|

2015

|

tom 66

|

nr 5

18

Characteristics of MNNG induced repair synthesis and DNA synthesis induced by human cytomegalovirus

63%

Anuszewska E., Koziorowska J.

Acta Biochimica Polonica

|

1989

|

tom 36

|

nr 2

19

Heparin inhibits protective effect of ischemic preconditioning in ischemia/reperfusion-induced acute pancreatitis

63%

Warzecha Z., Dembinski A., Ceranowicz P., Dembinski M., Sendur R., Cieszkowski J., Sendur P., Tomaszewska R.

Journal of Physiology and Pharmacology

|

2012

|

tom 63

|

nr 4

20

Mutation in DNA polymerase gamma cause error prone DNA synthesis in human mitochondrial disorders

63%

Copeland W. C., Ponamarev M. V., Nguyen D., Kunkel T. A., Longley M. J.

Acta Biochimica Polonica

|

2003

|

tom 50

|

nr 1

This paper summarizes recent advances in understanding the links between the cell's ability to maintain integrity of its mitochondrial genome and mitochondrial genetic diseases. Human mitochondrial DNA is replicated by the two-subunit DNA polγ- merase γ (pol γ). We investigated the fidelity of DNA replication by pol γ with and without exonucleolytic proofreading and its p55 accessory subunit. Pol γ has high base substitution fidelity due to efficient base selection and exonucleolytic proofreading, but low frameshift fidelity when copying homopolymeric sequences longer than four nucleotides. Progressive external ophthalmoplegia (PEO) is a rare disease characterized by the accumulation of large deletions in mitochondrial DNA. Recently, several mutations in the polymerase and exonuclease domains of the human pol γ have been shown to be associated with PEO. We are analyzing the effect of these mutations on the human pol γ enzyme. In particular, three autosomal dominant mutations alter amino acids located within polymerase motif B of pol γ. These residues are highly conserved among family A DNA polymerases, which include T7 DNA polymerase and E. coli pol I. These PEO mutations have been generated in pol γ to analyze their effects on overall polymerase function as well as the effects on the fidelity of DNA synthesis. One mutation in particular, Y955C, was found in several families throughout Europe, including one Belgian family and five unrelated Italian families. The Y955C mutant pol γ retains a wild-type catalytic rate but suffers a 45-fold decrease in apparent binding affinity for the incoming dNTP. The Y955C derivative is also much less accurate than is wild-type pol γ, with error rates for certain mismatches elevated by 10- to 100-fold. The error prone DNA synthesis observed for the Y955C pol γ is consistent with the accumulation of mtDNA mutations in patients with PEO. The effects of other pol γ mutations associated with PEO are discussed.

Ograniczanie wyników

Inhibitors of DNA polymerase beta inhibit base excision repair

An unexpected effect of 2-chloro-2'deoxyadenosine on DNA synthesis in EHEB cells

Caffeine-induced premature chromosome condesation [PCC] in the root meristem cells of Vicia faba

Day-to-night activity of bacteria in the surface microlayer eutrophic lake