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91.
Markus Islinger Ka Wan Li Jürgen Seitz Alfred Völkl Georg H. Lüers 《Traffic (Copenhagen, Denmark)》2009,10(11):1711-1721
Most newly synthesized peroxisomal proteins are imported in a receptor-mediated fashion, depending on the interaction of a peroxisomal targeting signal (PTS) with its cognate targeting receptor Pex5 or Pex7 located in the cytoplasm. Apart from this classic mechanism, heterologous protein complexes that have been proposed more than a decade ago are also to be imported into peroxisomes. However, it remains still unclear if this so-called piggyback import is of physiological relevance in mammals. Here, we show that Cu/Zn superoxide dismutase 1 (SOD1), an enzyme without an endogenous PTS, is targeted to peroxisomes using its physiological interaction partner 'copper chaperone of SOD1' (CCS) as a shuttle. Both proteins have been identified as peroxisomal constituents by 2D-liquid chromatography mass spectrometry of isolated rat liver peroxisomes. Yet, while a major fraction of CCS was imported into peroxisomes in a PTS1-dependent fashion in CHO cells, overexpressed SOD1 remained in the cytoplasm. However, increasing the concentrations of both CCS and SOD1 led to an enrichment of SOD1 in peroxisomes. In contrast, CCS-mediated SOD1 import into peroxisomes was abolished by deletion of the SOD domain of CCS, which is required for heterodimer formation. SOD1/CCS co-import is the first demonstration of a physiologically relevant piggyback import into mammalian peroxisomes. 相似文献
92.
93.
Tolar Tjaša Galik Alfred Le Bailly Matthieu Dufour Benjamin Caf Nina Toškan Borut Bužan Elena Zver Lars Janžekovič Franc Velušček Anton 《Vegetation History and Archaeobotany》2021,30(1):107-118
Vegetation History and Archaeobotany - Multi-proxy analysis of the coprolites which were found during excavations at two Late Neolithic (fourth millennium bc) pile-dwelling sites (Črnelnik and... 相似文献
94.
Julie Cattelotte Nicolas Tournier Nathalie Rizzo-Padoin† Alfred H. Schinkel‡ Jean-Michel Scherrmann Salvatore Cisternino§ 《Journal of neurochemistry》2009,108(3):767-775
Cationic 99m Tc-agents like 99m Tc-hexakis-2-methoxyisobutyl isonitrile (99m Tc-MIBI) cannot be used for brain imaging because they do not enter the brain as readily as some uncharged 99m Tc-compounds. The mechanism by which cationic 99m Tc-agents are transported across the blood–brain barrier (BBB) remains unclear. We explored 99m Tc-MIBI transport by in situ mouse brain perfusion to determine the influence of BBB features like the ATP-binding cassette transporters (Abcb1/P-glycoprotein (P-gp), Abcc1/Mrp1, and Abcg2/Bcrp), organic cation transporters (Slc22a1-3/Oct1-3), the transmembrane potential and the dipole membrane potential. P-gp reduced 99m Tc-MIBI transport across the BBB of P-gp-deficient mice 2.2-fold, as confirmed by PSC833 and GF120918 inhibition. Paradoxically verapamil decreased its transport '0.6-fold'. Reducing the BBB dipole membrane potential with tetraphenylborate or phloretin increased 99m Tc-MIBI transport about 12- and 20-fold, respectively. Guanidine, diphenhydramine, and carnitine significantly decreased 99m Tc-MIBI transport, but tetraethylammonium did not. 99m Tc-MIBI transport at the BBB is restricted by P-gp but not by Mrp1 or Bcrp. Some organic cations reduced the influx of 99m Tc-MIBI into the brain independently of Oct1, 2 and 3, but this could be due to their effect on another cation transporter. The membrane dipole potential of the luminal BBB membrane appeared to be the main factor restricting 99m Tc-MIBI permeability. 相似文献
95.
Ana E. Carmo-Silva Alfred J. Keys Jane L. Ward Nathaniel D. Hawkins Martin A.J. Parry 《Phytochemistry》2009,70(5):664-671
Plants produce various compounds in response to water deficit. Here, the presence and identification of a drought-inducible non-protein amino acid in the leaves of two C4 grasses is first reported. The soluble amino acids extracted from the leaves of three different species were measured by high-performance liquid chromatography of derivatives formed with o-phthaldialdehyde and β-mercaptoethanol. One amino acid that increased in amount with drought stress had a retention time not corresponding to any common amino acid. Its identity was determined by metabolite profiling, using 1H NMR and GC-MS. This unusual amino acid was present in the dehydrated leaves of Cynodon dactylon (L.) Pers. and Zoysia japonica Steudel, but was absent from Paspalum dilatatum Poir. Its identity as 2-amino-5-hydroxypentanoic acid (5-hydroxynorvaline, 5-HNV) was confirmed by synthesis and co-chromatography of synthetic and naturally occurring compounds. The amount of 5-HNV in leaves of the more drought tolerant C4 grasses, C. dactylon and Z. japonica, increased with increasing water deficit; therefore, any benefits from this unusual non-protein amino acid for drought resistance should be further explored. 相似文献
96.
97.
Claudia Hoffmann Alfred Blume Inge Miller Patrick Garidel 《European biophysics journal : EBJ》2009,38(5):557-568
Therapeutic proteins formulated as liquid solutions at high protein concentration are very sensitive to chemical and physical
degradation. Especially avoiding the formation of protein aggregates is very crucial for product quality. In order to stabilize
the colloidal properties of protein therapeutics various excipient are used. Especially the detergents polysorbate 20 and
80 are common. However, the mechanism upon which the detergents protect the protein from aggregation is not really known.
The present study investigates the interaction of polysorbate 20 and 80 with different proteins: lysozyme, bovine serum albumin
(BSA) and an immunoglobulin. The interaction and binding of the detergents to the proteins is investigated by isothermal titration
calorimetry (ITC). From ITC the thermodynamic parameters (ΔH: change in enthalpy, ΔS: entropy and ΔG: free energy) upon binding are derived as well as the binding constant K
a. The thermal stability of the proteins in the presence of the detergent is assessed by differential scanning calorimetry
(DSC). The results show that both detergents bind to BSA with K
a between 8 and 12 × 103 M−1 with ΔH −50 to −60 kJ/mol (25°C). One to two detergent molecules bind to BSA. The presence of both detergents induces a weak stabilisation
of the thermal denaturation properties of BSA. However, the interaction of polysorbate 20 and 80 with lysozyme and the immunoglobulin
is quite negligible. The presence of the detergents up to a concentration of 2 mM has no impact on the heat capacity curve
neither a destabilisation nor a stabilisation of the native conformation is observed. 相似文献
98.
99.
Alfred Posch 《Journal of Industrial Ecology》2010,14(2):242-257
Closing loops by intercompany recycling of by‐products is a core theme of industrial ecology (IE). This article considers whether industrial recycling networks or industrial symbiosis projects can be used as a starting point for much broader intercompany cooperation for sustainable development. Evidence presented is based on the results of an empirical investigation of the recycling network Styria in Austria, the recycling network Oldenburger Münsterland in Germany, and the manufacturing sector in Austria. Statistical analysis shows that the percentage of by‐products that are passed on to other companies for recycling purposes is not higher in member companies of the recycling networks than in the other companies of the manufacturing sector in Austria. In terms of cooperation, the relationships with the respective recycling partners are found to be very similar to regular customer relations. Furthermore, the companies of the recycling networks remain unaware of the network to which they belong. Instead, one of the main findings of this study is that intercompany recycling activities are regarded by the company representatives as bilateral market transactions, not as collaborative network activities. This has potentially significant implications for the use of industrial symbiosis networks as starting points for sustainability networks with broader cooperation toward sustainability. The findings raise interesting questions as to whether such broader cooperation might result from a conscious planning process or might emerge largely spontaneously as part of normal market coordination. In any case, intercompany recycling is clearly considered to be a very important field of collaborative action for sustainability in industry. 相似文献
100.
Shanmuga Sozhamannan Michael D Chute Farrell D McAfee Derrick E Fouts Arya Akmal Darrell R Galloway Alfred Mateczun Leslie W Baillie Timothy D Read 《BMC microbiology》2006,6(1):34-11