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11.
Shaltiel Shmuel Schvartz Iris Korc-Grodzicki Beatriz Kreizman Tamar 《Molecular and cellular biochemistry》1993,127(1):283-291
In addition to itsintra-cellular functions, cAMP-dependent protein kinase (PKA) may well have anextra-cellular regulatory role in blood. This suggestion is based on the following experimental findings: (a) Physiological stimulation of blood platelets brings about a specific release of PKA, together with its co-substrates ATP and Mg++; (b) In human serum, an endogenous phosphorylation of one protein (p75, Mr 75 kDa) occurs; this phosphorylation is enhanced by addition of cAMP and blocked by the Walsh-Krebs specific PKA inhibitor; (c) No endogenous phosphorylation of p75 occurs in human plasma devoid of platelets, but the selective labeling of p75 can be reproduced by adding to plasma the pure catalytic subunit of PKA; (d) p75 was shown to be vitronectin (V), a multifunctional protein implicated in processes associated with platelet activation, and thus a protein whose function may require modulation for control; (e) The phosphorylation of vitronectin occurs at one site (Ser378) which, at physiological pH, is buried in its two-chain form (V65+10) but becomes exposed in the presence of glycosaminoglycans (GAGs) e.g. heparin or heparan sulfate. Such a transconformation may be used for targeting the PKA phosphorylation to vitronectin molecules bound to GAGs, for example in the extracellular matrix or on cell surfaces; (f) From the biochemical point of view (Km values and physiological concentrations) the phosphorylation of vitronectin can take place at the locus of a hemostatic event; (g) The phosphorylation of Ser378 in vitronectin alters its function, since it significantly reduces its ability to bind the inhibitor-1 of plasminogen activator(s) (PAI-1). Physiologically, this functional modulation may be involved in unleashing PAI-1, allowing its translocation to control the inhibitory function of PAI-1 and, through it, regulating the conversion of plasminogen to active plasmin.Dedicated to Edmond H. Fischer and Edwin G. Krebs, with gratitude for teaching us the right measure of thoroughness and vision in research. 相似文献
12.
Markus Götz Jan Lask Iris Lewandowski Andrea Kruse 《Global Change Biology Bioenergy》2023,15(8):1011-1029
5-Hydroxymethylfurfural (HMF) is a versatile platform chemical for a fossil free, bio-based chemical industry. HMF can be produced by using fructose as a feedstock. Using edible, first-generation biomass to produce chemicals has been questioned in terms of potential competition with food supply. Second-generation biomass like miscanthus could be an alternative. However, there is a lack of information if second-generation lignocellulosic biomass is a more sustainable feedstock to produce HMF. Therefore, a life cycle assessment was performed in this study to determine the environmental impacts of HMF production from miscanthus and to compare it with HMF from high-fructose corn syrup (HFCS). HFCS from either Hungary or Baden-Württemberg (Germany) was considered. Compared to the HFCS biorefineries the miscanthus concept is producing less emissions in all impact categories studied, except land occupation. Overall, the production and usage of second-generation biomass could be especially beneficial in areas where the use of N fertilizers is restricted. Besides, conclusions for the further development of the on-farm biorefinery concept were elaborated. For this purpose, process simulations from a previous study were used. Results of the previous study in terms of TEA and the current LCA study in terms of environmental sustainability indicate that the lignin depolymerization unit in the miscanthus biorefinery has to be improved. The scenario without lignin depolymerization performs better in all impact categories. The authors recommend to not further convert the lignin to products like phenol and other aromatic compounds. The results of the contribution analyses show that the major impact in the HMF production is caused by the auxiliary materials in the separation units and the required heat. Further technical development should focus on efficient heat as well as solvent use and solvent recovery. At this point further optimizations will lead to reduced emissions and costs at the same time. 相似文献
13.
Anita Shepherd Danny Awty-Carroll Jason Kam Chris Ashman Elena Magenau Enrico Martani Mislav Kontek Andrea Ferrarini Stefano Amaducci Chris Davey Vanja Jurišić Gert-Jan Petrie Mohamad Al Hassan Isabelle Lamy Iris Lewandowski Emmanuel de Maupeou Jon McCalmont Luisa Trindade Kasper van der Cruijsen Philip van der Pluijm Rebecca Rowe Andrew Lovett Iain Donnison Andreas Kiesel John Clifton-Brown Astley Hastings 《Global Change Biology Bioenergy》2023,15(4):444-461
New biomass crop hybrids for bioeconomic expansion require yield projections to determine their potential for strategic land use planning in the face of global challenges. Our biomass growth simulation incorporates radiation interception and conversion efficiency. Models often use leaf area to predict interception which is demanding to determine accurately, so instead we use low-cost rapid light interception measurements using a simple laboratory-made line ceptometer and relate the dynamics of canopy closure to thermal time, and to measurements of biomass. We apply the model to project the European biomass potentials of new market-ready hybrids for 2020–2030. Field measurements are easier to collect, the calibration is seasonally dynamic and reduces influence of weather variation between field sites. The model obtained is conservative, being calibrated by crops of varying establishment and varying maturity on less productive (marginal) land. This results in conservative projections of miscanthus hybrids for 2020–2030 based on 10% land use conversion of the least (productive) grassland and arable for farm diversification, which show a European potential of 80.7–89.7 Mt year−1 biomass, with potential for 1.2–1.3 EJ year−1 energy and 36.3–40.3 Mt year−1 carbon capture, with seeded Miscanthus sacchariflorus × sinensis displaying highest yield potential. Simulated biomass projections must be viewed in light of the field measurements on less productive land with high soil water deficits. We are attempting to model the results from an ambitious and novel project combining new hybrids across Europe with agronomy which has not been perfected on less productive sites. Nevertheless, at the time of energy sourcing issues, seed-propagated miscanthus hybrids for the upscaled provision of bioenergy offer an alternative source of renewable energy. If European countries provide incentives for growers to invest, seeded hybrids can improve product availability and biomass yields over the current commercial miscanthus variety. 相似文献
14.
Iris Gruska Waltraut Jekabsons Wolfgang Schuster 《Molecular & general genetics : MGG》1995,247(5):529-536
We have characterized a mitochondrial gene in Oenothera, designated orf454, capable of encoding a component of the cytochrome c biogenesis system. This open reading frame is interrupted by an intron of 941 nucleotides showing high similarity to a group II intron residing in the rpl2 gene. RNA editing, which is observed at 18 cytidine positions within the orf454 reading frame, improves the similarity to protein-coding sequences in bacteria and higher plants and removes the last 16 amino acids. orf454 also shows high sequence similarity to two overlapping reading frames (orf169 and orf322) of Marchantia mitochondria. These ORFs belong to an operon-like cluster of genes in the liverwort that is not conserved in Oenothera mitochondria. However, in bacteria these reading frames are organized like the Marchantia gene cluster. It has been shown by genetical analysis in Rhodobacter capsulatus that these genes are essential for cytochrome c biogenesis. Genes of bacterial operons — ccl1 in Rhodobacter and yejR and nrfE in Escherichia coli — show high sequence similarity to the mitochondrial reading frames orf577 and orf454 of Oenothera. orf454, which we describe here, is homologous to the C-terminal region of these bacterial genes, while the previously described orf577 is homologous to the N-terminal region. 相似文献
15.
Sophie Lepage Bernard Lakaye Moreno Galleni Iris Thamm Michel Crine Sylvie Groslambert Jean-Marie Frère 《Molecular microbiology》1995,16(2):365-372
With the help of a new highly sensitive method allowing the quantification of free penicillin-binding proteins (PBPs) and of an integrated mathematical model, the progressive saturation of PBP1 by various β-lactam antibiotics in growing cells of Bacillus licheniformis was studied. Although the results confirmed PBP1 as a major lethal target for these compounds, they also underlined several weaknesses in our present understanding of this phenomenon. In growing cells, but not in resting cells, the penicillin target(s) appeared to be somewhat protected from the action of the inactivators. In vitro experiments indicated that amino acids, peptides and depsipeptides mimicking the peptide moiety of the nascent peptidoglycan significantly interfered with the acylation of PBP1 by the antibiotics. In addition, the level of PBP1 saturation at antibiotic concentrations corresponding to the minimum inhibitory concentrations was not constant, suggesting that additional, presently undiscovered, factors might be necessary to account for the experimental observations. 相似文献
16.
Summary Filamentous bacteria were isolated from bulking activated sludge and identified as Herpetosiphon spec. The Gram-negative filaments are more than 500 m long and they show gliding motility. The bacteria grown in artificial media (J- or EC-medium), in shaken cultures yield about 3 g cells per liter. Optimum growth was observed at 25°C and pH 7.2. The colonies are either uncoloured or bright red depending on the cultivation medium. The isolated bacteria exhibit lytic activity towards cells of Escherichia coli and Klebsiella pneumoniae. The G+C ratio of the five strains from different bulking sludge samples was found to be between 48.7 moles% and 49.0 moles%. 相似文献
17.
Iris B. Wilson Theodore E. Staley Linville J. Bush Stanley E. Gilliland 《Molecular and cellular biochemistry》1984,62(1):57-65
Summary Putative receptors for K88+ E. coli from piglet intestinal epithelium were released into the organ culture medium and were demonstrated by direct binding with K88+ E. coli through the utilization of an in vitro binding procedure or by immunoprecipitation with K88 antigen.Incorporation of 14C-glucosamine by newborn to day old and 3-week to 6-week old piglet jejunal and ileal mucosa, in organ culture, occurred throughout the 24 hr culture period. Uptake in both age groups and both areas of the intestine was similar with a somewhat greater incorporation by the older age group.Secretion of 14C-glucosamine-labeled components into the culture medium was demonstrated by gel filtration of the concentrated medium. Some large molecular weight components eluted in the void volume in excess of 2 x 106 daltons. A second peak of activity was spread from approximately 690K to 25K daltons. All eluted fractions demonstrated binding to K88+ E. coli.Antibodies to purified brush borders from susceptible pigs produced prominent precipitation bands following double diffusion with concentrated organ culture media which confirmed that the organ culture media contained labeled proteins of brush border origin.Immunoprecipitation of the intestinal mucosal organ culture media with K88+ pili and pilus antisera, followed by electrophoresis with SDS and reduced conditions, demonstrated a subunit of approximately 35K daltons. 相似文献
18.
Summary Studying the blood picture of 11 patients with Martin-Bell syndrome, we found the erythrocytes relatively hyperchromic when compared to the data from 171 matched controls living in the same institution. Because mean corpuscular hemoglobin is increased also in patients with folic acid deficiency states, we feel that our data provide further evidence that Martin-Bell syndrome is an inherited disease of folate metabolism.The data were first presented at the 18th Meeting of the Gesellschaft für Anthropologie und Humangenetik, Münster/Westf., October 5–8, 1983 相似文献
19.
20.
Characterization of Enkephalin Release from Rat Striatum 总被引:4,自引:4,他引:0
Abstract: Using antisera specific for methionine- and leucine-enkephalin, we studied the characteristics of the release of these peptides from rat striatal slices. Only 2–3% of the total tissue stores of enkephalin could be released by potassium depolarization; similar percentages were released from globus pallidus, thalamus, and nucleus accumbens. Enkephalin release from hippocampus could not be detected. The striatal release of both enkephalins was affected similarly by changes in potassium and calcium levels in the superfusion medium. Lithium has no effect on either basal or potassium-stimulated release; tyr-arg did not affect basal release of either peptide. Striatal enkephalin levels were stable during the short-term incubation periods used in these experiments. 相似文献