The dynamics of the non-heme iron in bacterial reaction centers from Rhodobacter sphaeroides

AbstractWe investigate the dynamical properties of the non-heme iron (NHFe) in His-tagged photosynthetic bacterial reaction centers (RCs) isolated from Rhodobacter (Rb.) sphaeroides. Mössbauer spectroscopy and nuclear inelastic scattering of synchrotron radiation (NIS) were applied to monitor the arrangement and flexibility of the NHFe binding site. In His-tagged RCs, NHFe was stabilized only in a high spin ferrous state. Its hyperfine parameters (IS=1.06±0.01mm/s and QS=2.12±0.01mm/s), and Debye temperature (θD0~167K) are comparable to those detected for the high spin state of NHFe in non-His-tagged RCs. For the first time, pure vibrational modes characteristic of NHFe in a high spin ferrous state are revealed. The vibrational density of states (DOS) shows some maxima between 22 and 33meV, 33 and 42meV, and 53 and 60meV and a very sharp one at 44.5meV. In addition, we observe a large contribution of vibrational modes at low energies. This iron atom is directly connected to the protein matrix via all its ligands, and it is therefore extremely sensitive to the collective motions of the RC protein core. A comparison of the DOS spectra of His-tagged and non-His-tagged RCs from Rb. sphaeroides shows that in the latter case the spectrum was overlapped by the vibrations of the heme iron of residual cytochrome c2, and a low spin state of NHFe in addition to its high spin one. This enabled us to pin-point vibrations characteristic for the low spin state of NHFe

Dipoid-Specific Genome Stability Genes of S. cerevisiae: Genomic Screen Reveals Haploidization as an Escape from Persisting DNA Rearrangement Stress

Maintaining a stable genome is one of the most important tasks of every living cell and the mechanisms ensuring it are similar in all of them. The events leading to changes in DNA sequence (mutations) in diploid cells occur one to two orders of magnitude more frequently than in haploid cells. The majority of those events lead to loss of heterozygosity at the mutagenesis marker, thus diploid-specific genome stability mechanisms can be anticipated. In a new global screen for spontaneous loss of function at heterozygous forward mutagenesis marker locus, employing three different mutagenesis markers, we selected genes whose deletion causes genetic instability in diploid Saccharomyces cerevisiae cells. We have found numerous genes connected with DNA replication and repair, remodeling of chromatin, cell cycle control, stress response, and in particular the structural maintenance of chromosome complexes. We have also identified 59 uncharacterized or dubious ORFs, which show the genome instability phenotype when deleted. For one of the strongest mutators revealed in our screen, ctf18Δ/ctf18Δ the genome instability manifests as a tendency to lose the whole set of chromosomes. We postulate that this phenomenon might diminish the devastating effects of DNA rearrangements, thereby increasing the cell's chances of surviving stressful conditions. We believe that numerous new genes implicated in genome maintenance, together with newly discovered phenomenon of ploidy reduction, will help revealing novel molecular processes involved in the genome stability of diploid cells. They also provide the clues in the quest for new therapeutic targets to cure human genome instability-related diseases

Preliminary petrographic characteristics of crystalline complex with calciphyres from the Slyudyanka Valley (Baikal Lake, Russia)

Przedmiotem analizy są skały z doliny znajdującej się w sąsiedztwie kamieniołomu Pieriewał w miejscowości Sludianka, w górach Chamar-Daban. Badania przeprowadzono przy użyciu mikroskopu optycznego i elektronowego z wykorzystaniem metody rentgenografii strukturalnej (XRD). W odsłonięciach, w zboczach doliny, występują łupki krystaliczne, marmury oraz żyły granitoidowe. Znajdują się tam też kalcyfiry bogate we flogopit, apatyt i diopsyd. Kompleks skał metamorficznych został przeobrażony w warunkach facji kordierytowo-biotytowo-almadynowej. Protolitem tych skał były prawdopodobnie osady piaskowcowo-mułowcowe. W utworach tych występują liczne skały węglanowe: diopsydowo-apatytowe kalcyfiry. W procesie odmładzania tektonicznego tego obszaru doszło do deformacji kompleksu skalnego oraz dźwigania go, a także do tworzenia licznych intruzji żyłowych.Rocks from the Slyudyanka valley (Khamar-Daban Mountain), near the Pierieval quarry, were analysed for petrographic characteristics. Rocks samples have been investigated with the use of optical and electron microscopes as well as XRD methods. The outcrops on the valley slopes reveal the presence of crystalline schists and marbles with granitoid veins. There are also calciphyres, rich in phlogopite, apatite and diopside. This complex was metamorphosed under the cordierite-biotite-almandine facies. In this rock complex, carbonate-diopside-apatite calciphyres are also present. The complex was deformed, uplifted and intruded by numerous granitoid veins during the process of tectonic rejuvenation of this area

Investigation of current and torque components in order to detect complicated damages of three-phase induction machine

W artykule opracowano metodę diagnostyczną dla złożonych uszkodzeń trójfazowej maszyny indukcyjnej, które rozwijają się zarówno w obwodzie stojana, jak i w wirniku. Ich wczesne wykrycie ma istotne znaczenie, gdyż staje się możliwe zapoczątkowanie systematycznego badania w trybie on-line rozwoju stopnia uszkodzenia i zaplanowanie remontu w dogodnym czasie. Wprowadzono metodę obliczania składowych prądów i momentu, których częstotliwość i amplituda mogą spełniać funkcję symptomów diagnostycznych pozwalających na ocenę rodzaju stanu awaryjnego oraz określanie stopnia uszkodzenia. Dla dwustronnej niesymetrii w stojanie i wirniku opracowano model matematyczny trójfazowej maszyny indukcyjnej przy wykorzystaniu zastępczego układu uzwojeń dwufazowych. Dla stanów ustalonych i nieustalonych maszyny wykonano przykładowe symulacje komputerowe, potwierdzające przydatność opracowanej metody.The paper deals with the diagnostic method elaborated for complicated damages of the three-phase induction machine; these faults appear both in the stator and in the rotor circuit. Early faultfinding is of great importance because it makes possible initation of the systematic on-line investigation of development of the damage degree and planning the repair in favourable time. The method of the calculation of current and torque components has been elaborated. The frequency and the amplitude of these quantities can fulfil a function of diagnostic symptoms making possible the determination of the type and degree of the fault. For two-sided asymmetry in the stator and in the rotor, the mathematical model of the three-phase induction machine has been elaborated using the equivalent system of two-phase windings. For the steady and transient states of the machine, the exemplary computer simulations were realized and the results of calculations have been confirmed usefulness of the elaborated method

Microfacies, foraminifers and carbon and oxygen isotopes in a basinal section of the Zechstein Limestone (Wuchiapingian): Bonikowo 2 borehole, western Poland

The Zechstein Limestone of the Bonikowo 2 borehole is composed of limestone with varied dolomite content and is slightly thicker (3.4 m) than other supposed condensed sections in SW Poland. The microfacies (mostly bioclastic wackestones-packstones) are characteristic of open marine limestone deposited in deep shelf environments. The common occurrence of echinoids in all parts of the section, except close to its top, indicates no essential change in sea water salinity. However, the palaeotemperature interpretation of the highest δ18O value of calcite recorded in the Bonikowo 2 borehole (+0.32‰) indicates a temperature of 22.9°C when a δ18O of water = 2‰ is assumed. The δ13C and δ18O curves for calcite and dolomite are similar in shape, and their mean values are similar: +1.8 ±1.5‰ for calcite, respectively, and +1.9 ±2.3‰ and –4.3 ±2.4‰, –3.8 ±4.3‰ for dolomite. There is a recrystallized interval in the lower part of the section with both δ13C and δ18O values reduced. This may be regarded as an aerobic equivalent of the Kupferschiefer. The diversity and abundance of foraminifers is significant throughout the section studied; lagenids prevail, and this is considered to be due to the dysaerobic conditions throughout the duration of deposition of the Zechstein Limestone

The effect of piperlongumine on endothelial and lung adenocarcinoma cells with regulated expression of profilin-1

Maciej Gagat,1 Marta Hałas-Wiśniewska,1 Wioletta Zielińska,1 Magdalena Izdebska,1 Dariusz Grzanka,2 Alina Grzanka1 1Department of Histology and Embryology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland; 2Department of Clinical Pathomorphology, Faculty of Medicine, Nicolaus Copernicus University in Toruń, Collegium Medicum in Bydgoszcz, Bydgoszcz, Poland Purpose: The aim of the study was to evaluate the effect of piperlongumine (2 and 4 µM) on endothelial EA.hy926 and lung adenocarcinoma A549 cells with regulated expression of profilin-1 (PFN1). Material and methods: The cytotoxicity of alkaloid was evaluated by MTT assay, while cell death was assessed using double staining with annexin V and propidium iodide. Subsequently, the level of PFN1 1) upregulation in EA.hy926 endothelial cells and 2) downregulation in A549 lung adenocarcinoma cells. The next step was the analysis of the effect of PFN1 manipulation on cytoskeletal proteins. Results: The results showed that piperlongumine may inhibit proliferation of EA.hy926 and A549 cell lines and also induce cell death in a dose-dependent manner. Furthermore, endothelial cells with PFN1 overexpression showed lower sensitivity to alkaloid and strengthening of cell–cell interactions. In the case of A549 cells, loss of PFN1 expression resulted in a lower percentage of early apoptotic cells, reorganization of F-actin and vimentin network, and reduction of migratory potential. Conclusion: We suggest that upregulation of PFN1 in endothelial cell line may stabilize the cell junctions. In turn, PFN1 downregulation in A549 cells probably suppresses cell migration and sensitizes cells to anticancer agents. Keywords: profilin-1, piperlongumine, lung cancer, endothelial cell, F-actin, lung adeno­carcinom

The sulphur and oxygen isotopic composition of Lower Cambrian anhydrites in East Siberia

Published sulphur and oxygen isotope age curves for the late Neoproterozoic-Early Cambrian time interval have been based on studies of sulphate intervals of the East Siberian salt giant. We report here on sulphur and oxygen measurements for sulphate dispersed in, or forming laminae in, the rock salt deposits in all Lower Cambrian basins of East Siberia. Sulphur isotope data for 26 samples of Lower Cambrian anhydrites from East Siberia range from +22.6 to +34.5‰. No difference was observed between different suites and between samples taken from anhydrite intercalations in rock salt and from water-insoluble residue in rock salt. Oxygen isotope data for 25 anhydrite samples range from +12.4 to +17.8‰, and thus δ18 O values have a smaller range of variation (5.5‰) than δ34 S (11.8‰) over the entire set of Lower Cambrian anhydrites. The great δ34 S variability observed in the Lower Cambrian of Siberia seems to reflect mixing of sulphates coming from the ocean and due to the riverine input. The lowest δ18 O values may indicate the input values from both the sources, whilst the highest value may result from isotope exchange between SO4 2- and water. Our results combined with data provided by previous workers could indicate a clear stratigraphic trend in δ34 S values, with a remarkable fall of ca. 9‰ in δ34 S value during the earliest Cambrian and then a slight rise in δ34 S values in the younger part of Early Cambrian. However, if only the highest values are taken, the measured values are compatible with seawater δ34 S 3 30‰ during the entire Early Cambrian. Sulphur isotopic composition of sulphate minerals did not be come heavier from the sulphate stage to ward the chloride stage

Carbon-13 in alpha-cellulose of oak latewood (Jędrzejów, Southern Poland) during the Maunder Minimum

We have studied the δ13C signature in latewood alpha-cellulose of an ancient oak (Quercus robur L.) from a Cisterian Abbey belfry in Jędrzejów (Southern Poland). The time scale for the delta 13C record during 1631-1765 AD was built on the basis of detailed dendrochronology studies. Techniques available for extraction of alpha-cellulose from small samples have been used, the mean value of alpha-cellulose extraction efficiency being ca. 35%. In the delta 13C record of alpha-cellulose the cooling between 1650-1700 AD is clearly visible as a decrease of about 1.5‰. This period is consistent with the interval of the lowest solaractivity between 1645 and 1715 AD, which is known as the Maunder Minimum. Anti-correlation between δ13C and δ13C during the Maunder Minimum was observed but δ13C record is delayed by about 30 years with respect to the Maunder Minimum