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961.
Eleftheria Polychronidou Ilias Kalamaras Andreas Agathangelidis Lesley-Ann Sutton Xiao-Jie Yan Vasilis Bikos Anna Vardi Konstantinos Mochament Nicholas Chiorazzi Chrysoula Belessi Richard Rosenquist Paolo Ghia Kostas Stamatopoulos Panayiotis Vlamos Anna Chailyan Nanna Overby Paolo Marcatili Anastasia Hatzidimitriou Dimitrios Tzovaras 《BMC bioinformatics》2018,19(14):414
962.
963.
964.
A Natural Hepatocyte Growth Factor/Scatter Factor Autocrine Loop in Myoblast Cells and the Effect of the Constitutive Met Kinase Activation on Myogenic Differentiation 总被引:7,自引:0,他引:7 下载免费PDF全文
965.
Luciano Lepri Massimo Del Bubba Rita Maggini Gian Paolo Donzelli Paola Galvan 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1997,704(1-2)
Pooled human milk was subjected to Holder pasteurization and storage at −20°C up to 90 days and examined for its content of fat and
-lactate and for lipid composition. This treatment reduced fats by 6% and
-lactate by at least 7%. In addition, pasteurization and storage induced triglyceride hydrolysis. The absolute amount of free fatty acids (FFAs) which was 0.5% after collection, doubled after pasteurization and rose even more after storage. Different FFA compositions were found by several authors using the same analytical method even for milk samples subjected to the same treatment. More detailed information on procedures must be given to explain the different results. 相似文献
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967.
Paolo Freguglia 《Theoretical biology forum》2002,95(3):413-428
In this paper we present an axiomatic theory of evolution which is inspired by the reading of a paper written by G.V. Schiaparelli in 1898. Schiaparelli was a famous astronomer, but he also studied the Darwinian ideas. We propose five axioms which can characterize the theory of evolution. We have also written these axioms using the language of the logic of predicates of first order with some constant monadic and dyadic predicates and appropriate functionals. But we can use other types of logic. So we can examine the concepts of species and of speciation. Then we introduce the interesting notion of generation distance. Moreover we give a theorem which establishes a geometrical model of our theory. If we analyze further the fourth axiom (which concerns the notion of generation distance) we can propose an elementary dynamical model by which we can represent possible evolutionary dynamics. These dynamics partially depend on random quantities. 相似文献
968.
Anna Maria Dursi Stefania Albrizio Giovanni Greco Sonia Mazzeo Maria R Mazzoni Etrore Novellino Paolo Rovero 《Journal of peptide science》2002,8(8):476-488
The C-terminal domain of the heterotrimeric G protein a-subunits plays a key role in selective activation of G proteins by their cognate receptors. Several C-terminal fragments of Galpha(s) (from 11 to 21 residues) were recently synthesized. The ability of these peptides to stimulate agonist binding was found to be related to their size. Galpha(s)(380-394) is a 15-mer peptide of intermediate length among those synthesized and tested that displays a biological activity surprisingly weak compared with that of the corresponding 21-mer peptide, shown to be the most active. In the present investigation, Galpha(s)(380-394) was subjected to a conformational NMR analysis in a fluorinated isotropic environment. An NMR structure, calculated on the basis of the data derived from conventional 1D and 2D homonuclear experiments, shows that the C-terminal residues of Galpha(s)(380-394) are involved in a helical arrangement whose length is comparable to that of the most active 21 -mer peptide. A comparative structural refinement of the NMR structures of Galpha(s)(380-394) and Galpha(s)(374-394)C379A was performed using molecular dynamics calculations. The results give structural elements to interpret the role played by both the backbone conformation and the side chain arrangement in determining the activity of the G protein C-terminal fragments. The orientation of the side chains allows the peptides to assume contacts crucial for the G protein/receptor interaction. In the 15-mer peptide the lack as well as the disorder of some N-terminal residues could explain the low biological activity observed. 相似文献
969.
The conventionally protected oligopeptides of the two homologous series Boc-(L -Ile)n-OMe and Boc-(D -aIle)n-OMe (n = 2–6) were synthesized in a standard stepwise fashion and their uv and CD spectra in 2,2,2-trifluoroethanol, and solid-state ir spectra were investigated. In addition, two oligomeric products derived from the NCAs of L -isoleucine and of D -allo-isoleucine and having a DP of 20 and 12, respectively, were studied in the solid state by x-ray and ir. No substantial differences between the properties of the diastereomeric oligomers in the solid state were noticed, a β-structure being very likely at least for the Boc-protected hexapeptides and the higher oligomers. In contrast, differences were observed between the spectroscopic properties of the diastereomeric oligopeptides, and especially of the hexapeptides, in trifluoroethanol solution. The different properties of the hexapeptides in solution were related to the existence, in the case of Boc-(L -Ile)6-OMe, of soluble molecular aggregates in which the peptide chains assume the β-conformation. These results provide an additional example of the influence of the configuration of asymmetric carbon atoms of the side chains on the conformational properties of peptide molecules in solution. 相似文献
970.
Paolo Ruzza Luigi Quintieri Alessio Osler Andrea Calderan Barbara Biondi Maura Floreani Andrea Guiotto Gianfranco Borin 《Journal of peptide science》2006,12(7):455-461
Cathepsin B is a cysteine protease that in tumor tissues is localized in both acidic lysosomes and extracellular spaces. It can catalyze the cleavage of peptide bonds by two mechanisms: endoproteolytic attack with a pH optimum around 7.4, and attack from the C-terminus with a pH optimum at 4.5-5.5. In this work, seven fluorescent, internally quenched, decapeptides have been synthesized using the prototypical cathepsin B selective substrate Z-Phe-Arg-AMC as a lead, and used to identify the structural factors determining the susceptibility of peptides to hydrolysis at acidic and neutral pH values. Each peptide differs from the others in one amino acid (residue 6) and contains a highly fluorescent Nma group linked to the alpha-amino function of the N-terminal Orn residue and a Dnp group linked to the side chain of the Lys(8) residue acting as a quencher. Proteolytic cleavage was monitored by measuring the increase of fluorescence at 440 nm upon excitation at 340 nm, and the cleavage sites were determined by HPLC followed by ESI-MS analysis. Peptides containing Ala or Phe at position 6 are good substrates for the enzyme at both pH 5.0 and 7.4. By contrast, those containing Glu, Asp, Lys or Val are not cleaved at all by cathepsin B at pH 7.4, and are poorly hydrolyzed at pH 5.0. These findings provide new information for the rational design of cathepsin B-activated peptide-containing anticancer drugs. 相似文献