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131.
Degradation of acrylic copolymers by white-rot fungi 总被引:4,自引:0,他引:4
Mai C Schormann W Majcherczyk A Hüttermann A 《Applied microbiology and biotechnology》2004,65(4):479-487
Various water-soluble homopolymers and copolymers of acrylamide (AAm) and acrylic acid (AA) which contained phenolic sites, such as guaiacol, lignin sulfonate (LS) and 3,4-dihydroxybenzoic acid (3,4-DHBA), were tested with regard to their degradability by white-rot fungi. Compared with Phanerochaete chrysosporium, Pleurotus ostreatus caused a significantly higher decrease in the average molecular weight (w) of most of the copolymers and the homopolymer under the applied culture conditions. However, the w of poly(guaiacol/AAm) increased significantly during incubation with Pl ostreatus. P. chrysosporium was able to reduce only the w of the poly(LS/AA) to a significant degree and not that of the other polymers. The mineralization rate of AAm and AA copolymers and terpolymers of AAm, AA and phenolics (LS, 3,4-DHBA, guiacol), which were tested with P. ostreatus and Trametes versicolor, turned out to be low (0.8–3.2%). While the rates of mineralization were similar among all polymers, the decrease in radioactivity from the culture media was higher with the terpolymers bearing phenolic sites. UV spectra of the culture media revealed that the phenolic sites in the terpolymers were significantly degraded by both fungi. Obviously, the degradation of phenolics within the polymer chain caused a higher decrease in w but did not significantly increase the mineralization rate. 相似文献
132.
Wieraszko A 《Bioelectromagnetics》2004,25(7):537-544
The influence of low repetition rate pulsed magnetic fields (LRMF) on the evoked potential (population spike) recorded from mouse hippocampal slices was investigated. LRMF were applied according to two protocols. In protocol A, LRMF applied with a constant strength (15 mT) and frequency ranging from 0.03 to 0.5 Hz resulted in an amplification of the potential. Although the frequency of 0.16 Hz was the most effective, enhancing the population spike by over 280%, it also caused an increase in spontaneous activity, seizures, and cessation of neuronal activity in 50% of the slices. In protocol B, LRMF were applied with a variable intensity (9-15 mT) and in cycles of different duration ranging from 5 to 20 min. While an increase in the amplitude of the population spike was observed in all slices exposed to LRMF applied according to protocol B, the longest exposure was the most effective. Neither seizures nor an increase in the spontaneous activity were observed in this group of the slices. These results support and extend our previous data and characterize further the relation between the pattern of applied magnetic fields and their influence on the nervous system. 相似文献
133.
134.
Pitt GR Batt AR Haigh RM Penson AM Robson PA Rooker DP Tartar AL Trim JE Yea CM Roe MB 《Bioorganic & medicinal chemistry letters》2004,14(17):4585-4589
A library of compounds targeted to the vasopressin/oxytocin family of receptors was screened for activity at a cloned human oxytocin receptor using a reporter gene assay. Potency and selectivity were optimised to afford compound 39, EC50 = 33 nM. This series of compounds represents the first disclosed, non-peptide, low molecular weight agonists of the hormone oxytocin (OT). 相似文献
135.
Characteristics of arylsulfatase in Russian sturgeon (Acipenser gueldenstaedti) semen 总被引:1,自引:0,他引:1
Sarosiek B Ciereszko A Kolman R Glogowski J 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2004,139(4):571-579
Spermatozoa of sturgeons (Acipenseriformes), unlike teleosts, possess an acrosome. This paper provides data concerning biochemical characteristics of arylsulfatase (AS), an acrosomal enzyme, found in Russian sturgeon spermatozoa and seminal plasma. The enzymes were purified by a four-step procedure, using n-butanol extraction, ion-exchange chromatography repeated twice and gel filtration. High purity of our enzymes was confirmed by silver staining electrophoresis and an immunological experiment. Kinetic parameters indicated that the purified enzymes belong to arylsulfatase type A. Similarity of the seminal plasma arylsulfatase to the spermatozoan enzyme showed us that arylsulfatase from seminal plasma might originate from damaged spermatozoa. The possible physiological consequences of the presence of arylsulfatase in Russian sturgeon semen are discussed. 相似文献
136.
Sanishvili R Pennycooke M Gu J Xu X Joachimiak A Edwards AM Christendat D 《Journal of structural and functional genomics》2004,5(4):231-240
The crystal structure of the hypothetical protein TA1238 from Thermoplasma acidophilum was solved with multiple-wavelength anomalous diffraction and refined at 2.0 A resolution. The molecule consists of a typical four-helix antiparallel bundle with overhand connection. However, its oligomerization into a trimer leads to a coiled "super-helix" which is novel for such bundles. Its central feature, a six-stranded coiled coil, is also novel for proteins. TA1238 does not have strong sequence homologues in databases, but shows strong structural similarity with some proteins in the Protein Data Bank. The function could not be inferred from the sequence but the structure, with some rearrangement, bears some resemblance to the active site region of cobalamin adenosyltransferase (TA1434). Specifically, TA1238 retains Arg104, which is structurally equivalent to functionally critical Arg119 of TA1434. For such conformational change, the overhand connection of TA1238 might need to be involved in a gating mechanism that might be modulated by ligands and/or by interactions with the physiological partners. This allowed us to hypothesize that TA1238 could be involved in cobalamin biosyntheses. 相似文献
137.
138.
Waksmundzka-Hajnos M Petruczynik A Dragan A Wianowska D Dawidowicz AL Sowa I 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2004,800(1-2):181-187
Analysis of plant material is an important task in chemotaxonomical investigations, in search of plants with pharmacological activity or in standardisation of plant drugs. The choice of optimal conditions for the analysis of plant material and effect of extraction method on the yield of furanocoumarins from Pastinaca sativa fruits were examined. The following extraction methods were used in experiments: exhaustive extraction in Soxhlet apparatus, ultrasonification (USAE) at 25 and 60 degrees C, microwave-assisted solvent extraction in open and closed system (MASE) and accelerated solvent extraction (ASE). In most cases, the yield of furanocoumarins was highest by use of ASE method as well as by ultrasonification at 60 degrees C. 相似文献
139.
Taner Z Sen Andrzej Kloczkowski Robert L Jernigan Changhui Yan Vasant Honavar Kai-Ming Ho Cai-Zhuang Wang Yungok Ihm Haibo Cao Xun Gu Drena Dobbs 《BMC bioinformatics》2004,5(1):1-11
Background
Protein-protein interactions play a critical role in protein function. Completion of many genomes is being followed rapidly by major efforts to identify interacting protein pairs experimentally in order to decipher the networks of interacting, coordinated-in-action proteins. Identification of protein-protein interaction sites and detection of specific amino acids that contribute to the specificity and the strength of protein interactions is an important problem with broad applications ranging from rational drug design to the analysis of metabolic and signal transduction networks.Results
In order to increase the power of predictive methods for protein-protein interaction sites, we have developed a consensus methodology for combining four different methods. These approaches include: data mining using Support Vector Machines, threading through protein structures, prediction of conserved residues on the protein surface by analysis of phylogenetic trees, and the Conservatism of Conservatism method of Mirny and Shakhnovich. Results obtained on a dataset of hydrolase-inhibitor complexes demonstrate that the combination of all four methods yield improved predictions over the individual methods.Conclusions
We developed a consensus method for predicting protein-protein interface residues by combining sequence and structure-based methods. The success of our consensus approach suggests that similar methodologies can be developed to improve prediction accuracies for other bioinformatic problems. 相似文献140.
Synthesis and in vitro testing of J591 antibody-dendrimer conjugates for targeted prostate cancer therapy 总被引:5,自引:0,他引:5
Targeted therapeutics using antibodies are an attractive option over conventional cancer chemotherapeutics due to their potential to deliver a therapeutic specifically to cancer tissue without damaging normal tissue. However, there are known problems with immunoconjugates such as decreased immunoreactivity and poor solubility. Using dendrimers as carriers for these agents has the potential to resolve these issues. We synthesized J591 anti-PSMA (prostate specific membrane antigen) antibody dendrimer conjugates containing fluorophores on the dendrimer. The in vitro studies of these conjugates show that they specifically bind to cells expressing PSMA. Confocal microscopy experiments document the binding and internalization of these conjugates. This research encourages the further study of antibody-dendrimer-drug conjugates for use in targeted therapeutics. 相似文献