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981.
Ingo Thievessen Peter M. Thompson Sylvain Berlemont Karen M. Plevock Sergey V. Plotnikov Alice Zemljic-Harpf Robert S. Ross Michael W. Davidson Gaudenz Danuser Sharon L. Campbell Clare M. Waterman 《The Journal of cell biology》2013,202(1):163-177
In migrating cells, integrin-based focal adhesions (FAs) assemble in protruding lamellipodia in association with rapid filamentous actin (F-actin) assembly and retrograde flow. How dynamic F-actin is coupled to FA is not known. We analyzed the role of vinculin in integrating F-actin and FA dynamics by vinculin gene disruption in primary fibroblasts. Vinculin slowed F-actin flow in maturing FA to establish a lamellipodium–lamellum border and generate high extracellular matrix (ECM) traction forces. In addition, vinculin promoted nascent FA formation and turnover in lamellipodia and inhibited the frequency and rate of FA maturation. Characterization of a vinculin point mutant that specifically disrupts F-actin binding showed that vinculin–F-actin interaction is critical for these functions. However, FA growth rate correlated with F-actin flow speed independently of vinculin. Thus, vinculin functions as a molecular clutch, organizing leading edge F-actin, generating ECM traction, and promoting FA formation and turnover, but vinculin is dispensible for FA growth. 相似文献
982.
Jelena Dragišić Maksimović Jingyi Zhang Fanrong Zeng Branka D. Živanović Lana Shabala Meixue Zhou Sergey Shabala 《Plant and Soil》2013,365(1-2):141-155
Aims
A causal relationship between salinity and oxidative stress tolerance and a suitability of using root antioxidant activity as a biochemical marker for salinity tolerance in barley was investigated.Methods
Net ion fluxes were measured from the mature zone of excised roots of two barley varieties contrasting in their salinity tolerance using non-invasive MIFE technique in response to acute and prolonged salinity treatment. These changes were correlated with activity of major antioxidant enzymes; ascorbate peroxidase, catalase, and superoxide dismutase.Results
It was found that genotypic difference in salinity tolerance was largely independent of root integrity, and observed not only for short-term but also long-term NaCl exposures. Higher K+ retention ability (and, hence, salinity tolerance) positively correlated with oxidative stress tolerance. At the same time, antioxidant activities were constitutively higher in a sensitive but not tolerant variety, and no correlation was found between SOD activity and salinity tolerance index during large-scale screening.Conclusion
Although salinity tolerance in barley correlates with its oxidative stress tolerance, higher antioxidant activity at one particular time does not correlate with salinity tolerance and, as such, cannot be used as a biochemical marker in barley screening programs. 相似文献983.
Sergey N. Gavrilov Jonathan R. Lloyd Nadezhda A. Kostrikina Alexander I. Slobodkin 《Geomicrobiology journal》2013,30(9):804-819
Physiological strategies driving the reduction of poorly crystalline Fe(III) oxide by the thermophilic Gram-positive dissimilatory Fe(III)-reducing bacterium C. ferrireducens were evaluated. Direct cell-to-mineral contact appears to be the major physiological strategy for ferrihydrite reduction. This strategy is promoted by cell surface-associated c-type cytochromes, and the extracellular electron transfer to ferrihydrite is linked to energy generation via a membrane-bound electron transport chain. The involvement of pili-like appendages in ferrihydrite reduction has been detected for the first time in a thermophilic microorganism. A supplementary strategy for the utilization of a siderophore (DFO) in dissimilatory ferrihydrite reduction has also been characterized. 相似文献
984.
Mark P. Little Tamara V. Azizova Dimitry Bazyka Simon D. Bouffler Elisabeth Cardis Sergey Chekin Vadim V. Chumak Francis A. Cucinotta Florent de Vathaire Per Hall John D. Harrison Guido Hildebrandt Victor Ivanov Valeriy V. Kashcheev Sergiy V. Klymenko Olivier Laurent Kotaro Ozasa Soile Tapio Andrew M. Taylor Ioanna Tzoulaki Wendy L. Vandoolaeghe Richard Wakeford Lydia Zablotska Wei Zhang Steven E. Lipshultz 《Radiation and environmental biophysics》2013,52(1):157-159
985.
Igor Abaev Juli Foster-Frey Olga Korobova Nina Shishkova Natalia Kiseleva Pavel Kopylov Sergey Pryamchuk Mathias Schmelcher Stephen C. Becker David M. Donovan 《Applied microbiology and biotechnology》2013,97(8):3449-3456
Staphylococcus aureus is a notorious pathogen highly successful at developing resistance to virtually all antibiotics to which it is exposed. Staphylococcal phage 2638A endolysin is a peptidoglycan hydrolase that is lytic for S. aureus when exposed externally, making it a new candidate antimicrobial. It shares a common protein organization with more than 40 other reported staphylococcal peptidoglycan hydrolases. There is an N-terminal M23 peptidase domain, a mid-protein amidase 2 domain (N-acetylmuramoyl-L-alanine amidase), and a C-terminal SH3b cell wall-binding domain. It is the first phage endolysin reported with a secondary translational start site in the inter-lytic-domain region between the peptidase and amidase domains. Deletion analysis indicates that the amidase domain confers most of the lytic activity and requires the full SH3b domain for maximal activity. Although it is common for one domain to demonstrate a dominant activity over the other, the 2638A endolysin is the first in this class of proteins to have a high-activity amidase domain (dominant over the N-terminal peptidase domain). The high activity amidase domain is an important finding in the quest for high-activity staphylolytic domains targeting novel peptidoglycan bonds. 相似文献
986.
Jafar Hasan Hayden K. Webb Vi Khanh Truong Sergey Pogodin Vladimir A. Baulin Gregory S. Watson Jolanta A. Watson Russell J. Crawford Elena P. Ivanova 《Applied microbiology and biotechnology》2013,97(20):9257-9262
The nanopattern on the surface of Clanger cicada (Psaltoda claripennis) wings represents the first example of a new class of biomaterials that can kill bacteria on contact based solely on its physical surface structure. As such, they provide a model for the development of novel functional surfaces that possess an increased resistance to bacterial contamination and infection. Their effectiveness against a wide spectrum of bacteria, however, is yet to be established. Here, the bactericidal properties of the wings were tested against several bacterial species, possessing a range of combinations of morphology and cell wall type. The tested species were primarily pathogens, and included Bacillus subtilis, Branhamella catarrhalis, Escherichia coli, Planococcus maritimus, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Staphylococcus aureus. The wings were found to consistently kill Gram-negative cells (i.e., B. catarrhalis, E. coli, P. aeruginosa, and P. fluorescens), while Gram-positive cells (B. subtilis, P. maritimus, and S. aureus) remained resistant. The morphology of the cells did not appear to play any role in determining cell susceptibility. The bactericidal activity of the wing was also found to be quite efficient; 6.1?±?1.5?×?106 P. aeruginosa cells in suspension were inactivated per square centimeter of wing surface after 30-min incubation. These findings demonstrate the potential for the development of selective bactericidal surfaces incorporating cicada wing nanopatterns into the design. 相似文献
987.
Alina P. Ryumina Ekaterina O. Serebrovskaya Marina V. Shirmanova Ludmila B. Snopova Maria M. Kuznetsova Ilya V. Turchin Nadezhda I. Ignatova Natalia V. Klementieva Arkady F. Fradkov Boris E. Shakhov Elena V. Zagaynova Konstantin A. Lukyanov Sergey A. Lukyanov 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Genetically encoded photosensitizers are a promising optogenetic instrument for light-induced production of reactive oxygen species in desired locations within cells in vitro or whole body in vivo. Only two such photosensitizers are currently known, GFP-like protein KillerRed and FMN-binding protein miniSOG. In this work we studied phototoxic effects of miniSOG in cancer cells.Methods
HeLa Kyoto cell lines stably expressing miniSOG in different localizations, namely, plasma membrane, mitochondria or chromatin (fused with histone H2B) were created. Phototoxicity of miniSOG was tested on the cells in vitro and tumor xenografts in vivo.Results
Blue light induced pronounced cell death in all three cell lines in a dose-dependent manner. Caspase 3 activation was characteristic of illuminated cells with mitochondria- and chromatin-localized miniSOG, but not with miniSOG in the plasma membrane. In addition, H2B-miniSOG-expressing cells demonstrated light-induced activation of DNA repair machinery, which indicates massive damage of genomic DNA. In contrast to these in vitro data, no detectable phototoxicity was observed on tumor xenografts with HeLa Kyoto cell lines expressing mitochondria- or chromatin-localized miniSOG.Conclusions
miniSOG is an excellent genetically encoded photosensitizer for mammalian cells in vitro, but it is inferior to KillerRed in the HeLa tumor.General significance
This is the first study to assess phototoxicity of miniSOG in cancer cells. The results suggest an effective ontogenetic tool and may be of interest for molecular and cell biology and biomedical applications. 相似文献988.
989.
990.
Sergey A. Streltsov Larissa P. Martinkina Alexander A. Khorlin Vladimir L. Florentiev Yuri Yu. Vengerov Sophia M. Zhenodarova 《Journal of biomolecular structure & dynamics》2013,31(6):1403-1415
Abstract The fluorescence, flow linear dichroism and electron microscopy (EM) have shown the trivaline ability to interact in solution with certain molecules of trinucleotides. This interaction results in formation of extended structures up to several. thousand angstroms in length. Such structures were observed for trivaline complexes with homopurine, homopyrimidine or random sequences of deoxyribo- and ribonucleotides, independently of the presence or absence of the terminal 5′-phosphate residue. A model of such a structural organization is proposed. An elementary structural unit consists of a trivaline β-dimer and adsorbed trinucleotide. So, “dimeric” complex is formed. Two such “dimeric” complexes combine with each other by means of peptide-peptide contacts (as with β-sandwich). So, “tetrameric” complex is formed It has a dyad axis. Two such structural units combine with each other by means of Hoogsteen's hydrogen bonds. So, “octamreic” complex is formed. It has three mutually perpendicular dyad axes. The “octameric” complexes appear to be able to combine with each other by means of stacking interactions, and to form the regular organized aggregates consisting of many dozens of elementary units. So, “stacking” structure is formed. The “octameric” complex is the symmetry translational unit of such a stucture. The spatial position of the bases in all these structures is additionally fixed by the nucleo-peptide interactions. These aggregates have the appearance of extended structures on electron micrographs. 相似文献