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101.
Powierska-Czarny J Miścicka-Sliwka D Czarny J Grzybowski T Wozniak M Drewa G Czechowicz W Sir J 《Acta biochimica Polonica》2003,50(4):1195-1203
Analysis of microsatellite instability (MI) and loss of heterozygosity (LOH) is recommended for screening patients with sporadic and hereditary malignancies. This study shows an application of a fluorescent hexaplex PCR system for microsatellite typing on A.L.F. DNA Sequencer (Pharmacia Biotech). This technique detects changes in microsatellites providing a time-efficient, reliable and accurate method for MI and LOH analyses. The Fragment Manager software was used for automated size calculation and quantitation of DNA fragments, enabling rapid and precise measurement of allelic ratios. We examined 70 breast cancer and 70 control DNA specimens, classified all the patterns of microsatellite alterations, and set up MI and LOH assessment criteria for the automated multiplex fluorescent method. 相似文献
102.
Alejandra Martinez Gonzalo Peluffo Ariel A. Petruk Martín Hugo Dolores Pi?eyro Verónica Demicheli Diego M. Moreno Analía Lima Carlos Batthyány Rosario Durán Carlos Robello Marcelo A. Martí Nicole Larrieux Alejandro Buschiazzo Madia Trujillo Rafael Radi Lucía Piacenza 《The Journal of biological chemistry》2014,289(18):12760-12778
Trypanosoma cruzi, the causative agent of Chagas disease, contains exclusively iron-dependent superoxide dismutases (Fe-SODs) located in different subcellular compartments. Peroxynitrite, a key cytotoxic and oxidizing effector biomolecule, reacted with T. cruzi mitochondrial (Fe-SODA) and cytosolic (Fe-SODB) SODs with second order rate constants of 4.6 ± 0.2 × 104
m−1 s−1 and 4.3 ± 0.4 × 104
m−1 s−1 at pH 7.4 and 37 °C, respectively. Both isoforms are dose-dependently nitrated and inactivated by peroxynitrite. Susceptibility of T. cruzi Fe-SODA toward peroxynitrite was similar to that reported previously for Escherichia coli Mn- and Fe-SODs and mammalian Mn-SOD, whereas Fe-SODB was exceptionally resistant to oxidant-mediated inactivation. We report mass spectrometry analysis indicating that peroxynitrite-mediated inactivation of T. cruzi Fe-SODs is due to the site-specific nitration of the critical and universally conserved Tyr35. Searching for structural differences, the crystal structure of Fe-SODA was solved at 2.2 Å resolution. Structural analysis comparing both Fe-SOD isoforms reveals differences in key cysteines and tryptophan residues. Thiol alkylation of Fe-SODB cysteines made the enzyme more susceptible to peroxynitrite. In particular, Cys83 mutation (C83S, absent in Fe-SODA) increased the Fe-SODB sensitivity toward peroxynitrite. Molecular dynamics, electron paramagnetic resonance, and immunospin trapping analysis revealed that Cys83 present in Fe-SODB acts as an electron donor that repairs Tyr35 radical via intramolecular electron transfer, preventing peroxynitrite-dependent nitration and consequent inactivation of Fe-SODB. Parasites exposed to exogenous or endogenous sources of peroxynitrite resulted in nitration and inactivation of Fe-SODA but not Fe-SODB, suggesting that these enzymes play distinctive biological roles during parasite infection of mammalian cells. 相似文献
103.
Angel López Piñeiro Enrique Saiz 《International journal of biological macromolecules》1983,5(1):37-41
The Rotational Isomeric States model is applied to calculate dipole moments of polypeptides of the twenty natural α-amino acids in the random coil state. Dipole moments of each repeat unit (μi), are evaluated using a quantum mechanics procedure. Dipole moment ratios () of homopolypeptides are calculated and extrapolated to x →?. With a few exceptions, D? = 0.36 ± 0.1. Ten actual proteins and three enzymes are also studied; their dipole ratios (Dx′ =〈μ〉/x) range from 7.34 to 10.57 in 10?59 C2 m2 (6.6–9.5 D2). Diffferences in the values of Dx′ are due mainly to the different contributions, μi, of the amino acid residues contained in each polymer, whereas the sequence of amino acids has a very minor effect. 相似文献
104.
Description of diatoms from the Southwest to West Greenland coastal and open marine waters 总被引:1,自引:0,他引:1
Diana W. Krawczyk Andrzej Witkowski Joanna J. Waniek Marcin Wroniecki Jan Harff 《Polar Biology》2014,37(11):1589-1606
Detailed studies on sub-Arctic and Arctic marine diatom assemblages contribute to the understanding of spatial distribution patterns and their physical drivers. In this study, diatom species were analyzed from water samples collected with a Niskin bottle rosette combined with a CTD along the West Greenland coast (63°58′N–71°08′N and 50°49′W–59°06′W) during summer 2007. Diatom community was represented mainly by three genera Thalassiosira, Fragilariopsis, and Chaetoceros and linked to observed hydrographic and environmental conditions. Thalassiosira spp. were common in coastal waters (particularly Godthåbsfjord) and linked to increased surface water temperature, typical of summer water stratification in West Greenland. Fragilariopsis spp., along with other dominant species associated with higher geographic latitudes, dominated in Arctic fjords (Uummannaq Fjord-Qaumarujuk Fjord). These species generally characterized coastal waters influenced by melting sea ice and/or glacial ice. Chaetoceros spp. were linked to more saline open marine waters, particularly in the Davis Strait south of 70°N, probably corresponding to weaker water stratification and the influence of the West Greenland Current. The present paper provides new knowledge on diatom assemblages along a south–north climate gradient in West Greenland, which is necessary in order to understand how observed ocean-climate changes influence Arctic marine ecosystems. This study provides a reference for palaeoenvironmental reconstructions using diatom microfossils deposited in the West Greenland marine sediments. 相似文献
105.
The study was conducted to investigate the nutritional value of five samples of raw and extruded pea seeds (Pisum sativum L., Tarachalska cv.) from different experimental fields. The study included 150 male 1-day-old Ross 308 chickens, which were randomly assigned to three dietary treatments (50 replications each) and kept in individual cages. From days 1 to 16, all birds received only the basal diets. From days 17 to 21, the control group received still the basal diet, but for the two other groups, 20% of basal diet was replaced by raw or extruded peas. Furthermore, the groups receiving raw or extruded peas were divided into five subgroups of 10 animals each, where the diets contained one of the five pea samples of the same cultivar grown at different locations, respectively. On days 19 and 20, excreta were individually collected, and then all chickens were sacrificed and ileal digesta were sampled for determination of ileal digestibility, which was calculated by the difference method. Extrusion of pea seeds decreased the contents of crude fibre, acid and neutral detergent fibre, trypsin inhibitor activity (TIA), phytic P and resistant starch (RS) (p ≤ 0.05), but increased the contents of apparent metabolisable energy (AMEN) by approximately 2.25 MJ/kg dry matter (DM). Furthermore, extrusion improved the DM and crude protein digestibility significantly by about 21.3% and 11.6%, respectively. Similar results were observed for the digestibility of all analysed amino acids. In conclusion, extrusion markedly influenced the chemical composition of peas, reduced their contents of phytic P, TIA and RS and consequently had a positive impact on nutrient digestibility and AMEN values. 相似文献
106.
Little is known about the architecture and biochemical composition of the eukaryotic DNA replication fork. To study this problem, we used biotin-streptavidin-modified plasmids to induce sequence-specific replication fork pausing in Xenopus egg extracts. Chromatin immunoprecipitation was employed to identify factors associated with the paused fork. This approach identifies DNA pol alpha, DNA pol delta, DNA pol varepsilon, MCM2-7, Cdc45, GINS, and Mcm10 as components of the vertebrate replisome. In the presence of the DNA polymerase inhibitor aphidicolin, which causes uncoupling of a highly processive DNA helicase from the stalled replisome, only Cdc45, GINS, and MCM2-7 are enriched at the pause site. The data suggest the existence of a large molecular machine, the "unwindosome," which separates DNA strands at the replication fork and contains Cdc45, GINS, and the MCM2-7 holocomplex. 相似文献
107.
Novel gene and gene model detection using a whole genome open reading frame analysis in proteomics 总被引:3,自引:1,他引:3
Fermin D Allen BB Blackwell TW Menon R Adamski M Xu Y Ulintz P Omenn GS States DJ 《Genome biology》2006,7(4):R35-13
Background
Defining the location of genes and the precise nature of gene products remains a fundamental challenge in genome annotation. Interrogating tandem mass spectrometry data using genomic sequence provides an unbiased method to identify novel translation products. A six-frame translation of the entire human genome was used as the query database to search for novel blood proteins in the data from the Human Proteome Organization Plasma Proteome Project. Because this target database is orders of magnitude larger than the databases traditionally employed in tandem mass spectra analysis, careful attention to significance testing is required. Confidence of identification is assessed using our previously described Poisson statistic, which estimates the significance of multi-peptide identifications incorporating the length of the matching sequence, number of spectra searched and size of the target sequence database. 相似文献108.
Witwicka H Kobiałka M Siednienko J Mitkiewicz M Gorczyca WA 《Biochimica et biophysica acta》2007,1773(2):209-218
It has been shown that cyclic GMP (cGMP) modulates the inflammatory responses of macrophages, but the underlying molecular mechanisms are still poorly understood. Looking for proteins potentially regulated by cGMP in rat peritoneal macrophages (PMs), in this study we analyzed expression and activity of cGMP-hydrolyzing and cGMP-regulated phosphodiesterases (PDEs). It was found that freshly isolated peritoneal exudate macrophages (PEMs) express enzymes belonging to families PDE1-3, PDE5, PDE10, and PDE11. Analysis of substrate specificity, sensitivity to inhibitors, and subcellular localization showed that PDE2 and PDE3 are the main cGMP-regulated PDE isoforms in PEMs. The profile of PDE expression was altered by maintaining PEMs in culture and treatment with bacterial endotoxin (LPS). After 24 h culture, PDE5 was not present and the levels of PDE2, PDE3, and PDE11 were markedly decreased. However, their expression and activity was recovered after treatment of cultured cells with LPS. A similar pattern of changes was observed for the expression of TNFalpha, but not for guanylyl cyclase A (GC-A). LPS up-regulated PDE expression also in resident peritoneal macrophages (RPMs), although not all PDEs present in PEMs were detected in RPMs. Taken together, our results show that in rat PMs expression of cGMP-dependent PDEs positively correlates with the activation state of cells. Moreover, the fact that most of these PDEs hydrolyze also cAMP indicates that cGMP can play a role of potent regulator of cAMP signaling in macrophages. 相似文献
109.
Two‐dimensional fluorescence as soft sensor in the monitoring of biotransformation performed by yeast 下载免费PDF全文
Marcin Zabadaj Karolina Chreptowicz Jolanta Mierzejewska Patrycja Ciosek 《Biotechnology progress》2017,33(2):299-307
Soft sensors are powerful tools for bioprocess monitoring due to their ability to perform online, noninvasive measurement, and possibility of detection of multiple components in cultivation media, which in turn can provide tools for the quantification of more than one metabolite/substrate/product in real time. In this work, soft sensor based on excitation‐emission fluorescence is for the first time applied for the monitoring of biotransformation production of 2‐phenylethanol (2‐PE) by yeast strains. Main process parameters—such as optical density, glucose, and 2‐PE concentrations—were determined with high accuracy and precision by fluorescence fingerprinting coupled with partial least squares regression. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:299–307, 2017 相似文献
110.
The synthesis of tetra- and octa-(7-oxy-3-methyl-4-phenylcoumarin)-substituted indium(III) phthalocyanine complexes obtained from 3-nitrophthalonitrile, 4-nitrophthalonitrile and 4,5-dichlorophthalonitrile substituted with 7-oxy-3-methyl-4-phenylcoumarin are described for the first time in this study. The new compounds have been characterized by elemental analysis, IR, 1H NMR, electronic spectroscopy and mass spectra. The photophysical and photochemical properties of the compounds are also studied in dimethylformamide (DMF). The effects of the number of the substitution and the position on the photophysical and photochemical parameters of the substituted indium(III) phthalocyanine complexes are also reported. Photophysical and photochemical properties of phthalocyanine complexes are very useful for photodynamic therapy (PDT) of cancer applications. In particular, high singlet-oxygen quantum yields are very important for Type II mechanisms. These complexes have good singlet-oxygen quantum yields and show potential as Type II photosensitizers. 相似文献