Wyniki wyszukiwania - Biblioteka Nauki

1

Tyrosine phosphatases as a superfamily of tumor suppressors in colorectal cancer

100%

Laczmanska I. , Sasiadek M. M.

Acta Biochimica Polonica

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2011

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tom 58

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nr 4

467-470

EN

Phosphorylation and dephosphorylation processes catalyzed by numerous kinases and phosphorylases are essential for cell homeostasis and may lead to disturbances in a variety of vital cellular pathways, such as cell proliferation and differentiation, and thus to complex diseases including cancer. As over 80 % of all oncogenes encode protein tyrosine kinases (PTKs), protein tyrosine phosphatases (PTPs), which can reverse the effects of tyrosine kinases, are very important tumor suppressors. Alterations in tyrosine kinase and phosphatase genes including point mutations, changes in epigenetic regulation, as well as chromosomal aberrations involving regions critical to these genes, are frequently observed in a variety of cancers. Colorectal cancer (CRC) is one of the most common cancers in humans. CRCs occur in a familial (about 15 % of all cases), hereditary (about 5%) and sporadic (almost 75-80 %) form. As genetic-environmental interrelations play an important role in the susceptibility to sporadic forms of CRCs, many studies are focused on genetic alterations in such tumors. Mutational analysis of the tyrosine phosphatome in CRCs has identified somatic mutations in PTPRG, PTPRT, PTPN3, PTPN13 and PTPN14. The majority of these mutations result in a loss of protein function. Also, alterations in the expression of these genes, such as decreased expression of PTPRR, PTPRO, PTPRG and PTPRD, mediated by epigenetic mechanisms have been observed in a variety of tumors. Since cancer is a social and global problem, there will be a growing number of studies on alterations in the candidate cancer genes, including protein kinases and phosphatases, to determine the origin, biology and potential pathways for targeted anticancer therapy.

2

Combined effect of low-molecular-weight organic acids and creosote on phosphatase activities in sandy soil

75%

Telesiński A. , Płatkowski M. , Krzyśko-Łupicka T. , Pawłowska B. , Cybulska K. , Curyło K.

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nr 2

EN

This paper assesses the impact of creosote and low-molecular-weight organic acids (LMWOAs) on the activity of acid phosphomonoesterase, alkaline phosphomonoesterase, phosphotriesterase, and inorganic pyrophosphatase in soil. The experiment was carried out on loamy sand samples with organic carbon content of 8.71 g·kg-1, with the following variable factors: dosages of creosote: 0, 0.5%, and 2.5%; type of LMWOAs: oxalic acid, tartaric acid, and citric acid in the amount of 50 mmol·kg-1of soil; days of experiment: 1, 7, 14, 28, 56, 112. Obtained results showed that contamination with creosote caused decrease in the activity of soil phosphatases. The observed effect did not always increase with increase in the dosage of the pollutant. Among the assayed phosphatases, the biggest changes were noted in the activity of phosphomonoesterases. Application of LMWOAs to contaminated soil mainly effected the inhibition of phosphatase, especially the activity of acid phosphomonoesterase. Comparison of the effects of LMWOAs showed that the citric acid was the least toxic to soil phosphatases.

3

Biodegradation of diesel fuel in soils modified with compost or bentonite and with optimized strains of bacteria. Part II. Changes in microorganisms counts and activity

51%

Nowak A. , Nowak J. , Hawrot-Paw M. , Telesiński A. , Błaszak M. , Kłódka D. , Przybulewska K. , Smolik B. , Szymczak J.

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2008

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tom Vol. 15, nr 7

607-622

EN

During diesel fuel biodegradation in the sandy and the clay soil, changes in bacteria, actinomycetes and fungi counts were determined. These determinations included also the counts of specific microorganism groups, ie diesel fuel-resistant and diesel fuel-metabolising bacteria and amylolytic, proteolytic and lipolytic microorganisms. Also the activity of soil enzymes, ie of urease and acid and alkaline phosphatases, was determined. The obtained results point to the increase of bacteria and fungi counts accompanying diesel fuel biodegradation, with a decrease in the actinomycetes count. A notably large increase was stated for bacteria resistant to diesel fuel and for those capable of its biodegradation, in particular in the soil modified with compost additive. Also an increase in the count of amylolytic and proteolytic microorganisms was observed in soil microflora, but the largest one in that of lipolytic microorganisms. The activity of urease increased only in the clay soil modified with compost, whereas that of acid and alkaline phosphatases increased in the two examined soils, also more distinctly when compost was added. The application of bioaugmentation treatment induced stimulation of microorganism growth, in particular of those resistant to diesel fuel and those capable of its degradation.

PL

Podczas biodegradacji oleju napędowego w glebie lekkiej i ciężkiej określano zmiany liczebności bakterii, promieniowców i grzybów, jak również różnych grup drobnoustrojów: bakterii odpornych na olej napędowy, bakterii zdolnych do biodegradacji oleju napędowego oraz mikroorganizmów amylolitycznych, proteolitycznych i lipolitycznych. Określano także aktywność enzymów glebowych: ureazy oraz kwaśnych i zasadowych fosfataz. Uzyskane wyniki wskazują na zwiększenie liczebności bakterii i grzybów podczas biodegradacji oleju napędowego, przy równoczesnym zmniejszeniu liczebności promieniowców. Nastąpiło również znaczne zwiększenie ilości bakterii odpornych na obecność oleju napędowego oraz zdolnych do jego biodegradacji, zwłaszcza w glebie modyfikowanej dodatkiem kompostu. Obserwowano także zwiększenie ilości mikroorganizmów amylolitycznych i proteolitycznych, a w jeszcze większym stopniu lipolitycznych. Aktywność ureazy zwiększała się jedynie w glebie ciężkiej modyfikowanej kompostem, podczas gdy aktywność kwaśnych i zasadowych fosfataz rosła w obydwu badanych glebach, również w większym stopniu po zastosowaniu kompostu. Zabieg bioaugumentacji stymulował wzrost mikroorganizmów, zwłaszcza odpornych na olej napędowy oraz zdolnych do jego biodegradacji.

4

Enzymatic activity in soil contaminated with the Aurora 40 WG herbicide

51%

Baćmaga M. , Boros E. , Kucharski J. , Wyszkowska J.

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2012

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tom Vol. 38, nr 1

91-102

EN

Aurora 40 WG is a new generation herbicide for controlling dicotyledonous weeds. Its effect on the biochemical properties of soil has not been investigated to date. The aim of this study was to determine the effect of soil contamination with the Aurora 40 WG herbicide on the activity of dehydrogenases, urease, acid phosphatase and alkaline phosphatase. Soil samples with the granulometric composition of loamy sand and sandy clay loam were used in a pot experiment. The lowest herbicide dose was that recommended by the manufacturer, and the successive doses were 2-, 4- and 40-fold higher than the recommended dose. In selected treatments, soil was mixed with finely ground spring barley straw and basalt meal. The experiment was carried out for 50 days, in two series, in unsown soil and in soil sown with spring barley. Soil samples were analyzed on experimental day 25 and 50. The obtained results indicate that the Aurora 40 WG herbicide did not modify the enzymatic activity of soil. The biochemical activity of soil was largely determined by the date of analysis, the addition of barley straw and basalt meal, soil type and soil use. The investigated enzymes were marked by higher activity levels in sandy clay loam than in loamy sand. Barley sowing had a generally positive effect on the enzymatic activity of soil, excluding alkaline phosphatase whose activity was higher in unsown treatments. The addition of finely ground spring barley straw also enhanced the biochemical properties of soil, while no such effects were demonstrated by basalt meal.

5

Molecules released by helminth parasites involved in host colonization

51%

Dzik J. M.

Acta Biochimica Polonica

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2006

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tom 53

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nr 1

33-64

EN

Parasites are designed by evolution to invade the host and survive in its organism until they are ready to reproduce. Parasites release a variety of molecules that help them to penetrate the defensive barriers and avoid the immune attack of the host. In this respect, particularly interesting are enzymes and their inhibitors secreted by the parasites. Serine-, aspartic-, cysteine-, and metalloproteinases are involved in tissue invasion and extracellular protein digestion. Helminths secrete inhibitors of these enzymes (serpins, aspins, and cystatins) to inhibit proteinases, both of the host and their own. Proteinases and their inhibitors, as well as helminth homologues of cytokines and molecules containing phosphorylcholine, influence the immune response of the host biasing it towards the anti-inflammatory Th2 type. Nucleotide-metabolizing enzymes and cholinesterase are secreted by worms to reduce inflammation and expel the parasites from the gastrointestinal tract. An intracellular metazoan parasite, Trichinella spiralis, secretes, among others, protein kinases and phosphatases, endonucleases, and DNA-binding proteins, which are all thought to interfere with the host cellular signals for muscle cell differentiation. Secretion of antioxidant enzymes is believed to protect the parasite from reactive oxygen species which arise from the infection-stimulated host phagocytes. Aside from superoxide dismutase, catalase (rarely found in helminths), and glutathione peroxidase (selenium-independent, thus having a poor activity with H2O2), peroxiredoxins are probably the major H2O2-detoxifying enzymes in helminths. Secretion of antioxidant enzymes is stage-specific and there are examples of regulation of their expression by the concentration of reactive oxygen species surrounding the parasite. The majority of parasite-secreted molecules are commonly found in free-living organisms, thus parasites have only adapted them to use in their way of life.