The occurrence of the cis/trans geometric isomerism of myxoxanthophyll and 4-ketomyxoxanthophyll in the cyanobacterium Anabaena sp. PCC7120

The cyanobacteria of the genus Anabaena have recently been recognized as a potential source of secondary metabolites of pharmacological and biotechnological importance. In particular, myxoxanthophylls – specific carotenoid glycosides that accumulate in cyanobacterial cells, are attracting increasing interest. Anabaena (Nostoc) sp. PCC7120, a filamentous, mesophilic, nitrogen-fixing cyanobacterium, is a model organism used in biochemical and genetic studies. The carotenoid pool of Anabaena sp. PCC7120 consists of five main species of pigments, namely β-carotene, echinenone, canthaxanthin and two derivatives of myxoxanthophyll: myxoxanthophyll ((3R,2‘S)-myxol 2’-fucoside) and 4-ketomyxoxanthophyll ((3S,2’S)-4-ketomyxol 2’-fucoside). Recent findings show that the carotenoid biosynthesis pathway functions in Anabaena sp. PCC7120 cells are affected by environmental factors. Specifically, the balance between β-carotene and ketocarotenoids alters according to the temperature conditions. In this study, a new method, based on single-step liquid adsorption chromatography was developed and applied to separate a fraction containing myxoxanthophyll and 4-ketomyxoxanthophyll from Anabaena sp. PCC7120 cells. It was found that this method allowed a high purity fraction of carotenoid glycosides to be obtained from pigment pools as extracted from cyanobacterial cells. The subsequent analysis using the methods HPLC and LC/MS demonstrated that this fraction consists of a mixture of compounds with different retention times. On the basis of their fragmentation spectra and optical properties, these compounds were identified as geometrical isomers of myxoxanthophyll and 4-ketomyxoxanthophyll, including the dominant all-trans forms and less abundant cis forms. Proposals regarding the structures of myxoxanthophyll isomers are made

Photoinduction of seed germination in Arabidopsis thaliana is modulated by phototropins

Light exposure is an important environmental factor which breaks seed dormancy in many plant species. Phytochromes have been identified as playing a crucial role in perception of the light signal that releases seed germination in Arabidopsis. Phototropins (Phot1, Phot2) are blue/UV-photoreceptors in plants which mediate phototropic responses, chloroplast relocation, hypocotyl growth inhibition and stomata opening. We studied germination under different light conditions in Arabidopsis Phot1-null and Phot2-null mutants and in a double phot1phot2 mutant. Germination of single phot1 and phot2 mutants in darkness was much lower than in wildtype (WT) seeds, whereas double phot1phot2 mutant lacking both functional phototropins germinated at frequency comparable to WT seeds, irrespective of light and temperature conditions. Light treatment of imbibed seeds was essential for effective germination of phot1, irrespective of low-temperature conditioning. In contrast, cold stratification promoted dark germination of phot2 seeds after imbibition in dim light. Low germination frequency of phot1 seeds under low light intensity suggests that the presence of functional Phot1 might be crucial for effective germination at these conditions. The lower germination frequency of phot2 seeds under continuous light suggests that Phot2 might be responsible for stimulating germination of seeds exposed to direct daylight. Thus, the phototropin system may cooperate with phytochromes regulating the germination competence of seeds under different environmental conditions

Arabidopsis cyclin-dependent kinase gene Cdkg;2 is involved in organogenic responses induced in vitro

The Arabidopsis CDKG;2 gene encodes a putative cyclin-dependent Ser/Thr protein kinase of unknown biological function. This gene shows structural similarity to animal and human cyclin-dependent (PITSLRE) kinases. This study used the homozygous knockout cdkg;2 mutant based on T-DNA insertional line SALK_090262 to study the effect of mutation of the CDKG;2 gene on explant response and in vitro plant regeneration. For callus induction and proliferation, hypocotyls and cotyledons of 3-day-old seedlings of cdkg;2 and A. thaliana ecotype Col-0 were cultured on solid MS medium supplemented with 2,4-D (2 mg l-1). Organogenesis was induced after callus transfer on MS + TDZ (0.5 mg l-1). The initiation time of callus and shoot induction differed between the mutant and control cultures. Shoot regeneration after callus transfer on MS + TDZ was delayed in cdkg;2 (31 days versus 7 days in Col-0). Shoots formed on callus derived from Col-0 hypocotyls but not on cotyledon-derived callus; in cdkg;2, shoots developed on both callus types. Mutant shoots did not form roots, regenerants were dwarfed, and inflorescences had small bud-like flowers with a reduced corolla and generative organs. Abnormalities observed during cdkg;2 organogenesis suggest a role of CDKG;2 as a regulator of adventitious root initiation

EPR study of thylakoid membrane dynamics in mutants of the carotenoid biosynthesis pathway of Synechocystis sp. PCC6803

EPR spectroscopy using 5-doxylstearic acid (5-SASL) and 16-doxylstearic acid (16-SASL) spin probes was used to study the fluidity of thylakoid membranes. These were isolated from wild type Synechocystis and from several mutants in genes encoding selected enzymes of the carotenoid biosynthesis pathway and/or acyl-lipid desaturases. Cyanobacteria were cultivated at 25°C and 35°C under different light regimes: photoautotrophically (PAG) and/or in light-activated heterotrophic conditions (LAHG). The relative fluidity of membranes was estimated from EPR spectra based on the empirical outermost splitting parameter in a temperature range from 15°C to 40°C. Our findings demonstrate that in native thylakoid membranes the elimination of xanthophylls decreased fluidity in the inner membrane region under optimal growth conditions (25°C) and increased it under sublethal heat stress (35°C). This indicated that the overall fluidity of native photosynthetic membranes in cyanobacteria may be influenced by the ratio of polar to non-polar carotenoid pools under different environmental conditions

Variations in xanthophyll composition in etiolated seedlings of Arabidopsis thaliana correlate with protochlorophyllide accumulation

Protochlorophyllide (Pchlide) accumulation and xantophyll composition were studied in 5-day old etiolated seedlings of three ecotypes of Arabidopsis thaliana: Columbia (Col-0), Landsberg erecta (Ler) and Wassiliewska (Ws). The total Pchlide level as measured by fluorescence spectroscopy varied significantly between ecotypes. A rapid HPLC method revealed quantitative differences in carotenoid composition. It was found that in the Ler ecotype any enhanced accumulation of Pchlide correlates with an increased level of lutein, suggesting the role of enzymes involved in lutein synthesis in cross-regulation between chlorophyll and carotenoid biosynthetic pathways. The function of the dark-accumulated carotenoid pool in seedling de-etiolation is discussed

Detecting Security Violations Based on Multilayered Event Log Processing, Journal of Telecommunications and Information Technology, 2015, nr 4

design. First layer, named the event source layer, describes sources of information that can be used for misuse investigation. Transport layer represents the method of collecting event data, preserving it in the form of logs and passing it to another layer, called the analysis layer. This third layer is responsible for analyzing the logs' content, picking relevant information and generating security alerts. Last layer, called normalization layer, is custom software which normalizes and correlates produced alerts to raise notice on more complex attacks. Logs from remote hosts are collected by using rsyslog software and OSSEC HIDS with custom decoders and rules is used on a central log server for log analysis. A novel method of handling OSSEC HIDS alerts by their normalization and correlation is proposed. The output can be optionally suppressed to protect the system against alarm flood and reduce the count of messages transmitted in the network

Professors of the Faculty of Law and Administration of the Jagiellonian University

Biogramy ponad 250 profesorów Wydziału Prawa i Administracji UJ, prowadzących działalność dydaktyczną i naukową w okresie od reformy Kołłątajowskiej do czasów współczesnych (1780-2012)Biographies of the over 250 professors of the Faculty of Law and Administration of the Jagiellonian University, conducting their didactic and research activity between the Hugo Kołłątaj's reform and the present day

Konkurencyjność polskiego górnictwa węgla kamiennego jako dostawcy paliwa do produkcji energii elektrycznej i ciepła

The paper investigates the competitiveness of the Polish hard coal mining sector as a fuel source for heat and power generation. The main objective of the study is to make a quantitative assessment of the impact of the price relationship between domestic and imported steam coal on the consumption of domestic fine coal in the Polish heat and power generation sector. For this purpose, a long-term mathematical model of the Polish steam coal market is employed and scenarios that mimic the relationship between domestic and imported steam coal prices is developed. The following results are analysed: - the volume of total domestic steam coal consumption under the scenarios analysed, - the absolute difference in domestic steam coal consumption under the scenarios analysed in comparison with the scenario 0%, - the total imported and domestic steam coal consumption in the period analysed. In addition, the results were depicted in cartograms in order to present the distribution of domestic and imported coal consumption in the various regions of Poland. The results of the study indicate that the supply of steam coal in Poland can be completely covered by domestic mines when the price of domestic coal is from –40% to –20% lower than that of imported coal. For the remaining scenarios, the consumption of imported coal increases and reaches its highest value in the scenario +40%, in which imported coal covered of 71% of total steam coal consumption in Poland over the period. The conclusions presented in this paper provide valuable findings and policy insights into the competitiveness of domestic mines and management of domestic production both in Poland and other countries in which power generation systems are mostly dominated by coal.W artykule przeanalizowano konkurencyjność krajowego węgla energetycznego w porównaniu z węglem importowanym w kontekście jego wykorzystania do produkcji energii elektrycznej i ciepła. Przeprowadzona została ilościowa ocena wpływu relacji cenowej węgla krajowego do węgla importowanego na stopień wykorzystania poszczególnych źródeł dostaw węgli. W tym celu wykorzystany został długoterminowy model krajowego rynku węgla energetycznego oraz opracowane zostały scenariusze odzwierciedlające różne relacje cenowe pomiędzy surowcem krajowym a importowanym. Analizie poddano następujące wyniki: - wolumen całkowitego zapotrzebowania na węgiel kamienny energetyczny w krajowym systemie wytwarzania, - bezwzględną różnicę zapotrzebowania na krajowy węgiel w porównaniu ze scenariuszem referencyjnym, - sumaryczne zapotrzebowanie na węgiel krajowy i importowany w analizowanym okresie. Ponadto wyniki zostały zaprezentowane na kartogramach w celu przedstawienia zapotrzebowania na węgiel krajowy i importowany w poszczególnych regionach Polski. Wyniki przeprowadzonych badań wskazują, że zapotrzebowanie na węgiel energetyczny może być w całości pokryte przez paliwo produkowane w krajowych kopalniach, gdy jego cena jest niższa od węgla importowanego w zakresie od 20 do 40%. W pozostałych przypadkach zapotrzebowanie na surowiec importowany wzrasta i osiąga najwyższą wartość w scenariuszu zakładającym cenę węgla importowanego o 40% niższą w porównaniu z ceną węgla krajowego. Wyniki przeprowadzonej analizy umożliwiają sformułowanie wniosków dotyczących konkurencyjności krajowych kopalń i zarządzania krajową produkcją nie tylko w Polsce, ale również w innych państwach, w których dominującym paliwem jest węgiel kamienny