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Nanocząstki tlenku tytanu (IV). otrzymywanie, właściwości i zastosowanie

100%
Kosmala K., Szymańska R.
Kosmos
|
2016
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vol. 65
|
issue 2
235-245
PL
Tlenek tytanu od dawna był stosowany głównie w przemyśle budowlanym i farbiarskim. Rozdrobnienie jego cząstek do skali nano, dzięki czemu uzyskał nowe, zupełnie niespotykane właściwości znacznie rozszerzyło spektrum jego zastosowań. Oprócz zastosowań typowo przemysłowych (budownictwo, przemysł tekstylny, samochodowy), nanocząstki tlenku tytanu są wykorzystywane w medycynie, farmacji, jako dodatki do żywności czy środki wybielające w stomatologii. Ze względu na szerokie wykorzystanie, a przez to trwałą obecność w środowisku (w glebie, wodzie) rodzi się pytanie o jego oddziaływanie np. z roślinami. W przeciągu kilku ostatnich lat przeprowadzono badania nad wpływem nanocząstek tlenku tytanu na rośliny. Wyniki tych badań są sprzeczne, gdyż albo wykazują jego toksyczność, albo pozytywne działanie. W związku z tym konieczne są zakrojone na szeroką skalę badania, które pozwolą odpowiedzieć na pytanie czy obecność nanocząstek tlenku tytanu w środowisku nie stwarza niebezpieczeństwa dla organizmów żywych.
EN
Titanium dioxide has been used in the industry for a long time. In the form of nanoparticles this compound was found to exhibit a completely new and unique properties, which significantly extended the range of its possible applications. Apart from typical industrial applications (architecture, textiles, automotive), titanium dioxide nanoparticles are used in medicine, pharmacy, dentistry and as food ingredients. Due to its broad usage and thus stable presence in the environment, a question arise if titanium dioxide nanoparticles are safe for living organisms? In recent years several experiments were conducted to find whether titanium dioxide nanoparticles may exert any influence on plants. The results obtained are rather contradictory as they indicate occurrence of both toxic and promoting effects. Thus, a large-scale experiments are needed to resolve the question whether presence of the nanoparticles in the environment is safe or not for plants, animals and humans.
2
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Occurrence of neoxanthin and lutein epoxide cycle in parasitic Cuscuta species

100%
Kruk J., Szymańska R.
Acta Biochimica Polonica
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2008
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vol. 55
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issue 1
183-190
EN
In the present study, xanthophyll composition of eight parasitic Cuscuta species under different light conditions was investigated. Neoxanthin was not detected in four of the eight species examined, while in others it occurred at the level of several percent of total xanthophylls. In C. gronovii and C. lupuliformis it was additionally found that the neoxanthin content was considerably stimulated by strong light. In dark-adapted plants, lutein epoxide level amounted to 10-22% of total xanthophylls in only three species, the highest being for C. lupuliformis, while in others it was below 3%, indicating that the lutein epoxide cycle is limited to only certain Cuscuta species. The obtained data also indicate that the presence of the lutein epoxide cycle and of neoxanthin is independent and variable among the Cuscuta species. The xanthophyll cycle carotenoids violaxanthin, antheraxanthin and zeaxanthin were identified in all the examined species and occurred at the level found in other higher plants. The xanthophyll and lutein epoxide cycle pigments showed typical response to high light stress. The obtained results also suggest that the ability of higher plants to synthesize lutein epoxide probably does not depend on the substrate specificity of zeaxanthin epoxidase but on the availability of lutein for the enzyme.
3
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Fitosterole - występowanie i znaczenie dla człowieka

100%
Szymańska R., Kruk J.
|
EN
Phytosterols (plant sterols) are compounds widely distributed among the plant kingdom occurring in the highest amounts in plant oils. They can be classified into two groups: sterols and stanols, which have fully saturated sterol rings. The main interest in phytosterols is due to their cholesterol-lowering effect in human plasma which is important for their application in different food products as natural drugs protecting against arteriosclerosis and heart diseases. Moreover, it has been shown that phytosterols show also anticancer action against colon, breast and prostate cancer and have antioxidation properties.
4
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Identification of hydroxy-plastochromanol in Arabidopsis leaves

100%
Szymańska R., Kruk J.
Acta Biochimica Polonica
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2010
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vol. 57
|
issue 1
105-108
EN
In the present study we have identified hydroxy-plastochromanol in plants for the first time. This compound was found both in low light and high light-grown Arabidopsis plants, however, under high light stress its level was considerably increased. Hydroxy-plastochromanol accumulated also during ageing of leaves of low light-grown plants, similarly as in the case of other prenyllipids. Our results indicate that hydroxy-plastochromanol found in leaves is probably formed as a result of plastochromanol oxidation by singlet oxygen generated in photosystem II during photosynthesis. These data also support the hypothesis that plastochromanol is an efficient antioxidant in vivo, similarly as tocopherols and plastoquinol.
5
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Witamina e - metabolizm i funkcje

81%
Szymańska R., Nowicka B., Kruk J.
Kosmos
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2009
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vol. 58
|
issue 1-2
199-210
EN
Vitamin E belongs to the group of chemical compounds called tocochromanol. It is synthesized exclusively by plants but fulfills also numerous important functions in humans. In the present article the occurrence and biosynthesis of vitamin E in plants have been described, as well as its diverse functions in plants including antioxidant action. Moreover, the metabolism of vitamin E and physiological significance in humans have been presented.
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