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1.
Lee SM Grass G Rensing C Barrett SR Yates CJ Stoyanov JV Brown NL 《Biochemical and biophysical research communications》2002,295(3):616-620
The interactions between the plasmid-borne copper resistance determinant, pco, and the main copper export system in Escherichia coli have been investigated and no direct interaction has been found. The PcoE and PcoC proteins are periplasmic and PcoC binds one Cu ion per protein molecule. PcoA is also periplasmic and can substitute for the chromosomally encoded CueO protein. The pco determinant is proposed to exert its effect through periplasmic handling of excess copper ions and to increase the level of resistance to copper ions above that conferred by copA alone. 相似文献
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Cornelia Caragea Jivko Sinapov Adrian Silvescu Drena Dobbs Vasant Honavar 《BMC bioinformatics》2007,8(1):438
Background
Glycosylation is one of the most complex post-translational modifications (PTMs) of proteins in eukaryotic cells. Glycosylation plays an important role in biological processes ranging from protein folding and subcellular localization, to ligand recognition and cell-cell interactions. Experimental identification of glycosylation sites is expensive and laborious. Hence, there is significant interest in the development of computational methods for reliable prediction of glycosylation sites from amino acid sequences. 相似文献3.
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Copper is an essential component of life because of its convenient redox potential of 200-800 mV when bound to protein. Extensive insight into copper homeostasis has only emerged in the last decade and Enterococcus hirae has served as a paradigm for many aspects of the process. The cop operon of E. hirae regulates copper uptake, availability, and export. It consists of four genes that encode a repressor, CopY, a copper chaperone, CopZ, and two CPx-type copper ATPases, CopA and CopB. Most of these components have been conserved across the three evolutionary kingdoms. The four Cop proteins have been studied in vivo as well as in vitro and their function is understood in some detail. 相似文献
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Jivko V. Stoyanov Stefano Mancini Zen Huat Lu Frédéric Mourlane Kristian R. Poulsen Reinhard Wimmer & Marc Solioz 《FEMS microbiology letters》2010,302(1):69-75
Intracellular copper routing in Enterococcus hirae is accomplished by the CopZ copper chaperone. Under copper stress, CopZ donates Cu+ to the CopY repressor, thereby releasing its bound zinc and abolishing repressor–DNA interaction. This in turn induces the expression of the cop operon, which encodes CopY and CopZ, in addition to two copper ATPases, CopA and CopB. To gain further insight into the function of CopZ, the yeast two-hybrid system was used to screen for proteins interacting with the copper chaperone. This led to the identification of Gls24, a member of a family of stress response proteins. Gls24 is part of an operon containing eight genes. The operon was induced by a range of stress conditions, but most notably by copper. Gls24 was overexpressed and purified, and was shown by surface plasmon resonance analysis to also interact with CopZ in vitro . Circular dichroism measurements revealed that Gls24 is partially unstructured. The current findings establish a novel link between Gls24 and copper homeostasis. 相似文献
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Philipp Schlaefli Alessandro Bertolo Cherry Malonzo Tobias Poetzel Martin Baur Frank Steffen Jivko Stoyanov 《Journal of visualized experiments : JoVE》2015,(98)
Mesenchymal stem cells (MSCs) - usually obtained from bone marrow - often require expansion culture. Our protocol uses clinical grade urokinase to degrade clots in the bone marrow and release MSCs for further use. This protocol provides a rapid and inexpensive alternative to bone marrow resampling. Bone marrow is a major source of MSCs, which are interesting for tissue engineering and autologous stem cell therapies. Upon withdrawal bone marrow may clot, as it comprises all of the hematopoietic system. The resulting clots contain also MSCs that are lost for expansion culture or direct stem cell therapy. We experienced that 74% of canine bone marrow samples contained clots and yielded less than half of the stem cell number expected from unclotted samples. Thus, we developed a protocol for enzymatic digestion of those clots to avoid labor-intense and costly bone marrow resampling. Urokinase - a clinically approved and readily available thrombolytic drug – clears away the bone marrow clots almost completely. As a consequence, treated bone marrow aspirates yield similar numbers of MSCs as unclotted samples. Also, after urokinase treatment the cells kept their metabolic activity and the ability to differentiate into chondrogenic, osteogenic and adipogenic lineages. Our protocol salvages clotted blood and bone marrow samples without affecting the quality of the cells. This obsoletes resampling, considerably reduces sampling costs and enables the use of clotted samples for research or therapy. 相似文献
8.
David Pavlicek Jörg Krebs Simona Capossela Alessandro Bertolo Britta Engelhardt Jürgen Pannek Jivko Stoyanov 《Immunity & ageing : I & A》2017,14(1):22
Background
Individuals with a spinal cord injury (SCI), despite specialized rehabilitation and good health care, have a reduced life expectancy. Infectious diseases, such as pneumonias, infected pressure sores and urinary tract infections (UTI) have been identified as the leading causes of mortality. We hypothesise that a premature onset of immune frailty occurs in SCI, possibly caused also by recurrent urinary tract infections.A cross sectional study was performed comparing blood and urine samples between able bodied controls (n = 84) and persons with spinal cord injury (n = 85). The results were grouped according to age (below and above 60 years). Assessed were the abundancies of immune cells, the concentration of soluble biomarkers, the in vitro functioning of lymphocytes as well as phenotypic exhaustion of T-cells in blood and urine. Further, the leucocyte telomere length and the cytomegalovirus (CMV) serological status were compared between the groups.Results
We observed in people with SCI lower proportions of naïve T-cells, more memory T-cells, reduced T-cell proliferation and higher CMV prevalence compared to age-matched controls. SCI participants older than 60 years had a higher prevalence of UTI compared with SCI persons younger than 60 years.Conclusion
The immune system of people with SCI shows traits of an increased immunological strain and a premature onset of immune frailty. The role of UTI in the onset of immune frailty remains to be elucidated as we did not see significantly higher abundancies of circulating UTI-bacteria specific T-cell clones in persons with SCI. We assume that any impact of UTI on the immune system might be compartmentalized and locally restricted to the urinary tract.9.
Copper, silver, gold and other heavy metals are potentially toxic to cells. Copper is also essential and cellular levels must be carefully controlled. In contrast, there is no known biological role for silver or gold and they have not been recognized as metals that are under homeostatic control. Using a luminescent biosensor based of the Vibrio fischeri lux gene cluster under the control of the Escherichia coli copA promoter/CueR metal-responsive regulator, we could show that in E. coli, cytoplasmic copper and silver, but not gold, are regulated by the CopA ATPase, the major copper efflux pump. 相似文献
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Jeannine D. Rinderknecht Simone M. Goldinger Sima Rozati Jivko Kamarashev Katrin Kerl Lars E. French Reinhard Dummer Benedetta Belloni 《PloS one》2013,8(3)