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1

Modulation of FAD-dependent monooxygenase activity from aromatic compounds-degrading Stenotrophomonas maltophilia strain KB2

100%

Wojcieszyńska D., Greń I., Hupert-Kocurek K., Guzik U.

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2011

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vol. 58

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issue 3

421-426

EN

The purpose of this study was purification and characterization of phenol monooxygenase from Stenotrophomonas maltophilia strain KB2, enzyme that catabolises phenol and its derivatives through the initial hydroxylation to catechols. The enzyme requires NADH and FAD as a cofactors for activity, catalyses hydroxylation of a wide range of monocyclic phenols, aromatic acids and dihydroxylated derivatives of benzene except for catechol. High activity of this monooxygenase was observed in cell extract of strain KB2 grown on phenol, 2-methylphenol, 3-metylphenol or 4-methylphenol. Ionic surfactants as well as cytochrome P450 inhibitors or 1,4-dioxane, acetone and n-butyl acetate inhibited the enzyme activity, while non-ionic surfactants, chloroethane, ethylbenzene, ethyl acetate, cyclohexane, and benzene enhanced it. These results indicate that the phenol monooxygenase from Stenotrophomonas maltophilia strain KB2 holds great potential for bioremediation.

2

Synthesis and anti-HIV properties of novel 6-phenylselenenyl-5-propyluracils

100%

Miazga A., Felczak K., Siwecka M. A., Lipniacki A., Piasek A., Kulikowski T.

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2007

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vol. 54

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issue 4

863-868

EN

Novel 6-phenylselenenyl-5-propyluracils were synthesized from 5-propyluracil with the use of regioselective synthesis to give 1-[(2-hydroxyethoxy)-methyl]-6-phenylselenenyl-5-propyluracil (6), 1-ethoxymethyl-6-phenylselenenyl-5-propyluracil (9) and 1-benzyloxymethyl-6-phenylselenenyl-5-propyluracil (10). Interaction of these compounds with recombinant HIV-1 reverse transcriptase (RT) was evaluated using a non-isotopic colorimetric method. Compounds 9 and 10 exerted potent HIV RT inhibition (IC50 0.06 and 0.05 µM respectively) while compound 6 showed moderate inhibition (IC50 = 3.5 µM). Potent anti-HIV-1 activity in MT-2 cells inoculated by a syncythia-inducing HIV-1 (cat #3 strain) laboratory isolate was exerted by compounds 9 and 10 (EC50 0.62 µM and 0.025 µM, respectively), while compound 6 showed only moderate activity (IC50 = 4.1 µM). In addition, compound 10 showed very good in vitro therapeutic index (TI > 2046), indicating that it is a potential anti-HIV/AIDS drug.

3

Inhibition of mitochondrial bioenergetics: the effects on structure of mitochondria in the cell and on apoptosis.

100%

Lyamzaev K. G., Izyumov D. S., Avetisyan A. V., Yang F., Pletjushkina O. Y., Chernyak B. V.

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vol. 51

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issue 2

553-562

EN

The effects of specific inhibitors of respiratory chain, FoF1ATP synthase and uncouplers of oxidative phosphorylation on survival of carcinoma HeLa cells and on the structure of mitochondria in the cells were studied. The inhibitors of respiration (piericidingg, antimycin, myxothiazol), the F1-component of ATP synthase (aurovertin) and uncouplers (DNP, FCCP) did not affect viability of HeLa cells, apoptosis induced by TNF or staurosporin and the anti-apoptotic action of Bcl-2. Apoptosis was induced by combined action of respiratory inhibitors and uncouplers indicating possible pro-apoptotic action of reactive oxygen species (ROS) generated by mitochondria. Short-term incubation of HeLa cells with the mitochondrial inhibitors and 2-deoxyglucose followed by 24-48 h recovery resulted in massive apoptosis. Apoptosis correlated to transient (3-4 h) and limited (60-70%) depletion of ATP. More prolonged or more complete transient ATP depletion induced pronounced necrosis. The inhibitors of respiration and uncouplers caused fragmentation of tubular mitochondria and formation of small round bodies followed by swelling. These transitions were not accompanied with release of cytochrome c into the cytosol and were fully reversible. The combined effect of respiratory inhibitors and uncouplers developed more rapidly indicating possible involvement of ROS generated by mitochondria. More prolonged (48-72 h) incubation with this combination of inhibitors caused clustering and degradation of mitochondria.

4

Inhibitors of N-glycosylation as a potential tool for analysis of the mechanism of action and cellular localisation of glycoprotein P

100%

Wojtowicz K., Szaflarski W., Januchowski R., Zawierucha P., Nowicki M., Zabel M.

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EN

Multidrug resistance has for many years attracted attention of numerous investigators. Attempts have also been made to increase efficiency of anti-neoplastic therapy. For this reason, most of efforts have been devoted to analysing proteins engaged in the mechanism of multidrug resistance such as the N-glycosylated membrane protein glycoprotein P. Interestingly, glycosylation probably plays a significant role in the intracellular location and activity of modified proteins. Inhibitors of glycosylation have been demonstrated to alter the activity of glycoprotein P in various ways, depending on the cell line examined. These inhibitors markedly reduce multidrug resistance of cancer cells, thus promoting success of anti-neoplastic therapy. Here, we review the basic knowledge on N-glycosylation inhibitors, their effect on glycoprotein P and their therapeutic potential.

5

Inhibition of DNA repair glycosylases by base analogs and tryptophan pyrolysate, Trp-P-1.

88%

Speina E., Cieśla J. M., Grąziewicz M.-A., Laval J., Kazimierczuk Z., Tudek B.

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2005

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vol. 52

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issue 1

167-178

EN

DNA base analogs, 2,4,5,6-substituted pyrimidines and 2,6-substituted purines were tested as potential inhibitors of E. coli Fpg protein (formamidopyrimidine -DNA glycosylase). Three of the seventeen compounds tested revealed inhibitory properties. 2-Thioxanthine was the most efficient, inhibiting 50% of 2,6-diamino-4-hydroxy-5N-methyl-formamidopyrimidine (Fapy-7MeG) excision activity at 17.1 μM concentration. The measured Kgi was 4.44 ± 0.15 μM. Inhibition was observed only when the Fpg protein was first challenged to its substrate followed by the addition of the base analog, suggesting uncompetitive (catalytic) inhibition. For two other compounds, 2-thio- or 2-oxo-4,5,6-substituted pyrimidines, IC50 was only 343.3 ± 58.6 and 350 ± 24.4 μM, respectively. No change of the Fpg glycosylase activity was detected in the presence of Fapy-7MeG, up to 5 μM. We also investigated the effect of DNA structure modified by tryptophan pyrolysate (Trp-P-1) on the activity of base excision repair enzymes: Escherichia coli and human DNA glycosylases of oxidized (Fpg, Nth) and alkylated bases (TagA, AlkA, and ANPG), and for bacterial AP endonuclease (Xth protein). Trp-P-1, which changes the secondary DNA structure into non-B, non-Z most efficiently inhibited excision of alkylated bases by the AlkA glycosylase (IC50 = 1 μM). The ANPG, TagA, and Fpg proteins were also inhibited although to a lesser extent (IC50 = 76.5 μM, 96 μM, and 187.5 μM, respectively). Trp-P-1 also inhibited incision of DNA at abasic sites by the β-lyase activity of the Fpg and Nth proteins, and to a lesser extent by the Xth AP endonuclease. Thus, DNA conformation is critical for excision of damaged bases and incision of abasic sites by DNA repair enzymes.

6

Pdr12p-dependent and -independent fluorescein extrusion from baker's yeast cells

88%

Lushchak V., Abrat O., Międzobrodzki J., Semchyshyn H.

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2008

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vol. 55

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issue 3

595-601

EN

Fluorescein efflux from S. cerevisiae cells was measured to study the peculiarities of fluorescein transport system, which is important for yeast resistance to certain drugs and weak organic acid preservatives. Glucose-independent and glucose-stimulated fluorescein effluxes were characterized using iodoacetate, cyanide and orthovanadate, inhibitors of glycolysis, electron transport chain, and ATPases, respectively. It is supposed that in glucose-free medium fluorescein extrusion is ATP-dependent and the energy for this efflux is mainly provided by respiration. In glucose-containing medium, glycolysis plays a critical role for extrusion of fluorescein. The results indicate that acetic acid inhibits the fluorescein efflux from yeast cells. The inhibition constant of glucose-stimulated fluorescein efflux is significantly lower in parental strain than in two mutants defective in PDR12 (ABC-transporter Pdr12p) or WAR1 (transcription factor of Pdr12p). It can be suggested that the membrane protein Pdr12 is involved in fluorescein extrusion from the yeast cells, but component(s) other than Pdr12p is (are) also important.

7

Multifunctional role of plant cysteine proteinases

88%

Grudkowska M., Zagdańska B.

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vol. 51

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issue 3

609-624

EN

Cysteine proteinases also referred to as thiol proteases play an essential role in plant growth and development but also in senescence and programmed cell death, in accumulation of storage proteins such as in seeds, but also in storage protein mobilization. Thus, they participate in both anabolic and catabolic processes. In addition, they are involved in signalling pathways and in the response to biotic and abiotic stresses. In this review an attempt was undertaken to illustrate these multiple roles of cysteine proteinases and the mechanisms underlying their action.

8

Antivirals - current trends in fighting influenza

88%

Król E., Rychłowska M., Szewczyk B.

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EN

Influenza virus infection is a major source of morbidity and mortality worldwide. Due to the variable effectiveness of existing vaccines, especially in the early stages of an epidemic, antiviral drugs represent the first line of defense against the virus. Currently, there are two major classes of anti-influenza drugs approved by the FDA for clinical use: M2 protein inhibitors (amantadine and rimantadine) and neuraminidase inhibitors (zanamivir and oseltamivir). However, increasing resistance to these available influenza antivirals among circulating influenza viruses highlights the need to develop alternative approaches for the prevention and/or treatment of influenza. This review presents an overview of currently available drugs for influenza treatment as well as summarizes some new antiviral strategies that are now being tested covering agents targeting both the viral proteins and the host-virus interaction. We discuss their mechanisms of action, resistance and the therapeutic potential as new antiviral drug for use in future influenza pandemics. Additionally, combination therapy based on these drugs is also described.

9

Pharmacological versus genetic inhibition of heme oxygenase-1 - the comparison of metalloporphyrins, shRNA and CRISPR/Cas9 system

75%

Mucha O., Podkalicka P., Czarnek M., Biela A., Mieczkowski M., Kachamakova-Trojanowska N., Stepniewski J., Jozkowicz A., Dulak J., Loboda A.

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2018

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vol. 65

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issue 2

277-286

EN

Inhibition of heme oxygenase-1 (HO-1, encoded by HMOX1), a cytoprotective, anti-apoptotic and anti-inflammatory enzyme, may serve as a valuable therapy in various pathophysiological processes, including tumorigenesis. We compared the effect of chemical inhibitors - metalloporphyrins, with genetic tools - shRNA and CRISPR/Cas9 systems, to knock-down (KD)/knock-out (KO) HO-1 expression/activity. 293T cells were incubated with metalloporphyrins, tin and zinc protoporphyrins (SnPPIX and ZnPPIX, respectively) or were either transduced with lentiviral vectors encoding different shRNA sequences against HO-1 or were modified by CRISPR/Cas9 system targeting HMOX1. Metalloporphyrins decreased HO activity but concomitantly strongly induced HO-1 mRNA and protein in 293T cells. On the other hand, only slight basal HO-1 inhibition in shRNA KD 293T cell lines was confirmed on mRNA and protein level with no significant effect on enzyme activity. Nevertheless, silencing effect was much stronger when CRISPR/Cas9-mediated knock-out was performed. Most of the clones harboring mutations within HMOX1 locus did not express HO-1 protein and failed to increase bilirubin concentration after hemin stimulation. Furthermore, CRISPR/Cas9-mediated HO-1 depletion decreased 293T viability, growth, clonogenic potential and increased sensitivity to H2O2 treatment. In summary, we have shown that not all technologies can be used for inhibition of HO activity in vitro with the same efficiency. In our hands, the most potent and comprehensible results can be obtained using genetic tools, especially CRISPR/Cas9 approach.

10

Modes of inhibition of cysteine proteases.

75%

Rzychon M., Chmiel D., Stec-Niemczyk J.

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vol. 51

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issue 4

861-873

EN

Cysteine proteases are involved in many physiological processes and their hyperactivity may lead to severe diseases. Nature has developed various strategies to protect cells and whole organisms against undesired proteolysis. One of them is the control of proteolytic activity by inhibition. This paper presents the mechanisms underlying the action of proteinaceous inhibitors of cysteine proteinases and covers propeptides binding backwards relative to the substrate or distorting the protease catalytic centre similarly to serpins, the p35 protein binding covalently to the enzyme, and cystatins that are exosite binding inhibitors. The paper also discusses tyropins and chagasins that, although unrelated to cystatins, inhibit cysteine proteinases by a similar mechanism, as well as inhibitors of the apoptosis protein family that bind in a direction opposite to that of the substrate, similarly to profragments. Special attention is given to staphostatins, a novel family of inhibitors acting in an unusual manner.

11

The role of 5-α-reductase inhibition in supressing progression of male androgenetic alopecia − a postulate for further studies on possible application of saw palmetto extracts

51%

Piwecki M., Urban A., Pełszyńska J.

Annales Academiae Medicae Silesiensis

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2023

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issue 77

190-196

EN

The study presents the mechanism of male androgenetic alopecia (MAGA), with a focus on the role of the enzyme 5-α-reductase, which is responsible for converting testosterone, the primary male hormone, into its active form, dihydrotestosterone (DHT). The consequences of the DHT stimulation of androgen receptors (ARs) located in the X chromosome of dermal papilla cells (DPCs) are described. This leads to androgen-induced gene transcription, disrupted hair follicle nourishment, and most importantly, an accelerated transition from the anagen to the catagen phase. The study also discusses how this enzyme can be targeted by molecules acting as inhibitors. Furthermore, the justification for conducting more in-depth studies on the mechanisms of action involving extracts of saw palmetto (Serenoa repens) and their inhibitory effects on 5-α-reductase is presented. The study also advocates the identification and measurement of active substances present in saw palmetto extracts, with two promising phytosterolic compounds, stigmasterol and β-sitosterol, due to their demonstrated inhibitory activity on 5-α-reductase in extracts from other plant species. As part of the proposal to deepen the research, attention is drawn to the need to investigate the impact of saw palmetto extract on the hair growth cycle, hair follicle life cycle, various growth factors and angiogenesis, immune system activity, and oxidative stress. Other areas of observation for the action of saw palmetto extracts could include their use in combination with other plant extracts or therapeutic agents such as platelet-rich plasma or fibrin-rich plasma.

PL

W pracy przedstawiono mechanizm łysienia androgenowego u mężczyzn (male androgenetic alopecia – MAGA) z uwzględnieniem roli enzymu 5-α-reduktazy, która odpowiada za konwersję testosteronu, najważniejszego hormonu męskiego, do jego aktywnej formy – dihydrotestosteronu (DHT). Opisane zostały konsekwencje pobudzenia przez DHT receptorów androgenowych (androgen receptors – ARs), zlokalizowanych w chromosomie X komórek linii brodawkowej (dermal papilla cells – DPCs). Powoduje to transkrypcję genów uruchamianą przez androgeny, zostaje zaburzone odżywianie mieszka włosowego, ale przede wszystkim przyspieszeniu ulega moment zakończenia anagenu i przejścia do fazy katagenu. Przedstawiono również, w jaki sposób enzym ten może być poddawany działaniu molekuł pełniących funkcję jego inhibitorów. Ponadto zaprezentowano uzasadnienie dla prowadzenia bardziej dogłębnych badań poświęconych mechanizmom działania, w których ekstrakty palmy sabałowej (Serenoa repens) wywołują efekt inhibicji 5-α-reduktazy. Dodatkowo w pracy został zawarty postulat na rzecz rozpoznawania i pomiaru substancji aktywnych znajdujących się w ekstraktach palmy sabałowej, w tym dwóch najbardziej obiecujących związków fitosterolowych – stigmasterolu i β-sitosterolu – ze względu na udowodnioną już aktywność inhibitorową w stosunku do 5-α-reduktazy w ekstraktach z surowców pochodzących z innych gatunków roślin. W ramach postulatu na rzecz pogłębienia badań zwrócono uwagę na konieczność oceny wpływu stosowania ekstraktów z palmy sabałowej na cykl życia włosów, cykl życia mieszka włosowego, różne czynniki wzrostu i angiogenezę, a także aktywność układu immunologicznego czy stres oksydacyjny. Inne obszary obserwacji działania ekstraktów z palmy sabałowej mogłyby obejmować ich zastosowanie w terapiach w połączeniu z innymi ekstraktami roślinnymi lub środkami terapii, np. z osoczem bogatopłytkowym czy osoczem bogatym w fibrynę.

Refine search results

Modulation of FAD-dependent monooxygenase activity from aromatic compounds-degrading Stenotrophomonas maltophilia strain KB2

Synthesis and anti-HIV properties of novel 6-phenylselenenyl-5-propyluracils

Inhibition of mitochondrial bioenergetics: the effects on structure of mitochondria in the cell and on apoptosis.

Inhibitors of N-glycosylation as a potential tool for analysis of the mechanism of action and cellular localisation of glycoprotein P

Inhibition of DNA repair glycosylases by base analogs and tryptophan pyrolysate, Trp-P-1.

Pdr12p-dependent and -independent fluorescein extrusion from baker's yeast cells

Multifunctional role of plant cysteine proteinases

Antivirals - current trends in fighting influenza

Pharmacological versus genetic inhibition of heme oxygenase-1 - the comparison of metalloporphyrins, shRNA and CRISPR/Cas9 system

Modes of inhibition of cysteine proteases.

The role of 5-α-reductase inhibition in supressing progression of male androgenetic alopecia − a postulate for further studies on possible application of saw palmetto extracts