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1.
Shinsuke Hara H. Dorota Halicka Silvia Bruno Jianping Gong Frank Traganos Zbigniew Darzynkiewicz 《Experimental cell research》1996,223(2):372
Proteolysis is an early event of apoptosis which appears to be associated with activation of the endonuclease which is responsible for internucleosomal DNA cleavage. The present study was designed to reveal the possible role of proteolysis in other early events, such as chromatin condensation, nuclear breakdown, and destabilization ofin situDNA double-stranded structure. Apoptosis of human leukemic HL-60 cells and rat thymocytes was induced by different agents, including DNA topoisomerase inhibitors, an RNA antimetabolite, and the glucocorticosteroid, prednisolone. DNA degradation was evaluated by pulsed field and conventional gel electrophoresis and by the presence ofin situDNA strand breaks. DNA stability was estimated by the measure of its sensitivityin situto denaturation. Chromatin condensation, nuclear breakdown, and other morphological changes were monitored by interference contrast and UV microscopy following cell staining with the DNA-specific fluorochrome 4′,6-diamidino-2-phenylindole. Several irreversible or reversible serine protease inhibitors prevented internucleosomal DNA degradation, nuclear breakdown, and destabilization of DNA double-stranded structure. The effective inhibitors, however, did not prevent the onset of chromatin condensation, nor the loss of the fine structural framework, nor the initial step of DNA cleavage generating DNA fragments of ≥50 kb in size. The data indicate that in both cell systems the activity of proteases sensitive to the inhibitors tested is needed for internucleosomal DNA cleavage to occur. The data also suggest that these proteases may be involved in dissolution of the nuclear envelope. Because nuclear matrix proteins and histones stabilize DNAin situ,and the decrease in DNA stability which occurs during apoptosis is precluded by the inhibitors, it is likely that serine proteases may degrade DNA stabilizing proteins. The activity of these proteases, however, appears needed neither for DNA cleavage to ≥50-kb fragments nor for the onset of chromatin condensation which is associated with dissolution of the structural framework of the nucleus. 相似文献
2.
Anna Barańczyk-Kuźma Dorota Drobisz Kenneth L. Audus Ronald T. Borchardt 《Neurochemical research》1993,18(7):783-786
The substrate specificity and affinity of two forms of phenol sulfotransferase (PST) from Rhesus macaque brain cortex were studied. Catecholamines, their methylated metabolites (normetanephrine, metanephrine) and methylated precursor, -methylDOPA, were examined as substrates for both the cationic (PST I) and the anionic (PST II) forms of the enzyme. Sulfation of hypertensive drugs (phenylephrine, octopamine, metaraminol), hypotensive drugs (-methylDOPA, minoxidil), and related agents without a free hydroxy group on the benzene ring were also studied. Results indicated that both PST forms sulfated -methylDOPA and minoxidil, but only PST II transferred the sulfate group to catecholamines and most of the adrenergic agents examined. 相似文献
3.
Dorota Kwiatkowska 《American journal of botany》1992,79(8):904-913
The various primary vascular systems of shoots of Anagallis arvensis L. (Primulaceae) can be distinguished in relation to the number of leaves (two, three, or four) at each node. In this study, shoot segments (single intemodes and the nodes above them) were examined. The arrangement of segments within shoots was also recorded. The vasculature forms a closed system with the number of sets of bundles usually equal to twice the number of leaves. Irregularities are found in the following features of the system: the number of bundles composing leaf half-traces; occurrence of anastomosing bundles; the number of intemodes through which bundles extend; levels of leaf attachment to the stem at the node; and distribution of parenchyma within the vascular cylinder, which determines the number of bundles in sets and the number of bundle sets. The irregularities occur with different frequencies for segments exhibiting different phyllotactic patterns. Comparison of these frequencies leads to the following conclusions: anastomosing bundles occur only in decussate or trimerous shoot segments, whereas sets of bundles united within intemodes and displaced leaves occur only in tetramerous or trimerous ones; decrease of the number of bundles per leaf and displacement of leaves at the nodal level are correlated; variation between segments exhibiting the same phyllotactic pattern is greatest for trimerous, less for tetramerous, and least for decussate segments; the vascular system of decussate shoot segments is more stable than that of the other systems; and trimerous segments seem to be intermediate between the other two segment types. 相似文献
4.
Agnieszka Piwkowska Dorota Rogacka Irena Audzeyenka Stefan Angielski Maciej Jankowski 《Experimental cell research》2014
Hyperglycemia is a primary factor that disturbs podocyte function in the glomerular filtration process; this disturbance leads to the development of diabetic nephropathy, and ultimately, renal failure. Podocyte function may also be altered by biological agents that modify protein kinase activity, including the cGMP-activated protein kinase type Iα (PKGIα). We hypothesized that hyperglycemia-induced podocyte protein hyperpermeability was dependent on PKGIα activation, and that PKGIα was activated via dimerization induced by reactive oxygen species. This hypothesis was investigated in rat podocytes cultured in high glucose (HG, 30 mM). Protein expression was measured with Western blot and immunofluorescence. Podocyte permeability was measured with a transmembrane albumin flux assay. We found that HG increased podocyte permeability in long-term incubations (1, 3, and 5 days); permeability was increased by 66% on day 5. This effect was abolished with apocynin, a NAD(P)H inhibitor, and Rp-8-Br-cGMPS, a PKG inhibitor. It was also abolished by introducing small interfering RNAs (siRNAs) against Nox4 and PKGIα into cultured podocytes. Furthermore, HG increased PKGIα dimerization by 138% (0.23±0.04 vs. 0.54±0.09; P<0.05); this effect was abolished with a siRNA against Nox4. Our observations suggested that HG could increase albumin permeability across the podocyte filtration barrier via Nox4-dependent PKGIα dimerization. 相似文献
5.
Dorota Lachowska Łukasz Kajtoch Stanisław Knutelski 《Entomologia Experimentalis et Applicata》2010,135(1):105-118
We studied the occurrence of Wolbachia in relation to the systematics, ecology, and biology of 40 weevil species from central Europe. Identification of Wolbachia supergroups and phylogeny was performed on the basis of 16S rDNA, ftsZ, wsp, and hcpA sequences. Sixteen species (40%) were infected by Wolbachia. Six of these possess only supergroup A (15% of all studied species, 37.5% of the infected species), and four harbored only supergroup B (10 and 25%, respectively). Six species were infected by both supergroups A and B or their genomes harbored parts of these two supergroups (15 and 37.5%, respectively). No differences between Wolbachia supergroup frequencies were detected. There was almost no correlation between Wolbachia phylogeny and host systematics and phylogeny at the level of subfamily and tribe, because the representatives of both supergroups were detected in all the studied multi‐species tribes. Wolbachia strains were probably inherited from a common ancestor only in the case of the genus Strophosoma, where two of three analyzed species possessed bacteria which are genetically very close in all the studied genes. There was also only limited congruence between phylogenies obtained from the four studied genes. These results suggest horizontal transmission of Wolbachia strains between species and recombination events between different strains. A significant correlation was detected between infected and uninfected species in relation to mobility (flying species were 2× more frequently infected than non‐flying species), foraging (polyphagous species were 2.5× less frequently infected than mono‐ or oligophagous species), and reproductive mode (parthenogenetic weevils were infected nearly 2× as often as bisexuals). No differences were detected between mesophilous and xerothermophilous species, nor between those inhabiting open areas vs. arboreal species. However, these results might have been influenced by common ancestry among the studied weevils. Because weevils include many plant pests of economic importance, it is possible to use these data in developing alternative, biology‐based strategies for controlling them. 相似文献
6.
7.
Dorota A. Dobrzanska Matthew T. F. Lamaudière Jessica Rollason Lauren Acton Michael Duncan Sharon Compton John Simms Gareth D. Weedall Igor Y. Morozov 《Microbial biotechnology》2020,13(3):669-682
In agriculture, antibiotics are used for the treatment and prevention of livestock disease. Antibiotics perturb the bacterial gut composition but the extent of these changes and potential consequences for animal and human health is still debated. Six calves were housed in a controlled environment. Three animals received an injection of the antibiotic florfenicol (Nuflor), and three received no treatment. Faecal samples were collected at 0, 3 and 7 days, and bacterial communities were profiled to assess the impact of a therapy on the gut microbiota. Phylogenetic analysis (16S-rDNA) established that at day 7, antibiotic-treated microbiota showed a 10-fold increase in facultative anaerobic Escherichia spp, a signature of imbalanced microbiota, dysbiosis. The antibiotic resistome showed a high background of antibiotic resistance genes, which did not significantly change in response to florfenicol. However, the maintenance of Escherichia coli plasmid-encoded quinolone, oqxB and propagation of mcr-2, and colistin resistance genes were observed and confirmed by Sanger sequencing. The microbiota of treated animals was enriched with energy harvesting bacteria, common to obese microbial communities. We propose that antibiotic treatment of healthy animals leads to unbalanced, disease- and obese-related microbiota that promotes growth of E. coli carrying resistance genes on mobile elements, potentially increasing the risk of transmission of antibiotic resistant bacteria to humans. 相似文献
8.
Felde Vivian A. Flantua Suzette G. A. Jenks Cathy R. Benito Blas M. de Beaulieu Jacques-Louis Kuneš Petr Magri Donatella Nalepka Dorota Risebrobakken Bjørg ter Braak Cajo J. F. Allen Judy R. M. Granoszewski Wojciech Helmens Karin F. Huntley Brian Kondratienė Ona Kalniņa Laimdota Kupryjanowicz Mirosława Malkiewicz Małgorzata Milner Alice M. Nita Małgorzata Noryśkiewicz Bożena Pidek Irena A. Reille Maurice Salonen J. Sakari Šeirienė Vaida Winter Hanna Tzedakis Polychronis C. Birks H. John B. 《Vegetation History and Archaeobotany》2020,29(1):101-109
Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes... 相似文献
9.
Agnieszka Wencel Malgorzata Ciezkowska Monika Wisniewska Karolina E. Zakrzewska Dorota G. Pijanowska Krzysztof D. Pluta 《Biotechnology and bioengineering》2021,118(1):72-81
Diseases leading to terminal hepatic failure are among the most common causes of death worldwide. Transplant of the whole organ is the only effective method to cure liver failure. Unfortunately, this treatment option is not available universally due to the serious shortage of donors. Thus, alternative methods have been developed that are aimed at prolonging the life of patients, including hepatic cells transplantation and bridging therapy based on hybrid bioartificial liver devices. Parenchymal liver cells are highly differentiated and perform many complex functions, such as detoxification and protein synthesis. Unfortunately, isolated hepatocytes display a rapid decline in viability and liver‐specific functions. A number of methods have been developed to maintain hepatocytes in their highly differentiated state in vitro, amongst them the most promising being 3D growth scaffolds and decellularized tissues or coculture with other cell types required for the heterotypic cell‐cell interactions. Here we present a novel approach to the hepatic cells culture based on the feeder layer cells genetically modified using lentiviral vector to stably produce additional amounts of hepatocyte growth factor and show the positive influence of these coculture conditions on the preservation of the hepatic functions of the liver parenchymal cells' model—C3A cells. 相似文献
10.
Otylia Kowal-Bielecka Marek Bielecki Serena Guiducci Beata Trzcinska-Butkiewicz Ma?gorzata Michalska-Jakubus Marco Matucci-Cerinic Marek Brzosko Dorota Krasowska Lech Chyczewski Krzysztof Kowal 《Arthritis research & therapy》2013,15(3):R69