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441.
F Filira L Biondi B Scolaro M T Foffani S Mammi E Peggion R Rocchi 《International journal of biological macromolecules》1990,12(1):41-49
Sequential glycopeptides [Thr(beta-D-galactose)-Ala-Ala]n, with n ranging from 2 to 7, as models of natural antifreeze glycoproteins were synthesized by the continuous flow, solid phase procedure. The conformational properties of these materials in solution were investigated by c.d. and 1H-n.m.r. spectroscopy. In aqueous solution the c.d. pattern is practically independent of chain length and is very similar to that of natural antifreeze glycoproteins. The results are interpreted in terms of random coil structure. The absence of ordered structures is further confirmed by n.m.r. data. A small amount of ordered conformation can be induced either by increasing the temperature of the aqueous solution or by addition of TFE. The c.d. pattern of all glycopeptides in water at temperatures higher than 50 degrees C are compatible with the presence of a small amount of alpha-helix or 3(10) helix. Since the glyco-hexapeptide is too short to form an alpha-helix, the hypothesis is made that in the glycopeptides in water at high temperature a small amount of 3(10) helix is formed. The same is observed for the 21-residue glycopeptide in presence of 85% (v/v) TFE. In this medium, the c.d. data on the glyco-hexapeptide are more compatible with the presence of a small amount of beta-structure. 相似文献
442.
Cristiano Biondi Roberta Galeazzi Gianpaolo Littarru Lucedio Greci 《Free radical research》2013,47(4):399-404
1,4-Benzoquinone, coenzyme Q 0 and Q 10 were reacted with a series of hydrogen donors in the ESR cavity in the presence or absence of UVA irradiation. The signals of the radicals generated from the hydrogen donors or of those of the semiquinones were detected. The reaction mechanism was interpreted by a hydrogen atom transfer instead of the usual electron transfer mechanism on the basis of the redox potentials of the reactants and the Marcus theory. The hydrogen atom transfer is explained by the excited triplet state of quinones, which, on the basis of quantum mechanic calculations, may be reached even under visible light. In some cases, hydrogen atom transfer was also observed without irradiation, although to a lesser extent. 相似文献
443.
444.
M Gobbo L Biondi F Filira B Scolaro R Rocchi T Piek 《International journal of peptide and protein research》1992,40(1):54-61
Syntheses are described of some mono- and di-glycosylated analogues of vespulakinin 1. The solid phase procedure, based on the Fmoc chemistry, was used to prepare (Gal alpha)Thr3-vespulakinin 1, (Gal beta)Thr3-vespulakinin 1 and the di-glycosylated analogue ((Gal alpha)Thr3, (Gal alpha)Thr4-vespulakinin 1. The beta-glycosylated derivative was also prepared by the continuous flow variant of the Fmoc polyamide method. The synthesized glycopeptides were purified and characterized by amino acid analysis, optical rotation, analytical HPLC, 1H- and 13C-NMR and FAB-MS. Preliminary pharmacological experiments showed that the carbohydrate-free vespulakinin 1 is less active than bradykinin (about 0.3 times on a molar basis) when tested by guinea pig rectum contraction, and the two monoglycosylated analogues are equiactive (about 0.9 times the bradykinin activity). The most active derivative, the (Gal alpha)Thr3, (Gal alpha)Thr4-vespulakinin 1 analogue, was about 2.5 times as active as bradykinin. 相似文献
445.
446.
In fish liver catecholamines bind to beta-adrenoceptors (AR) and increase glucose release via cAMP augmentation. Alpha1-AR have recently been shown to mediate IP3 and Ca2+ elevation in catfish and eel hepatocytes, although their coupling to a physiological response has remained doubtful. We have perifused isolated catfish hepatocytes in Bio-Gel P4 columns with epinephrine in the presence of prazosin and/or propranolol, alpha- and beta-AR antagonists, respectively. Ten nM epinephrine stimulated glucose release approximately 3-fold, and this effect was completely antagonized by the simultaneous presence of both alpha- and beta-AR blockers. The two AR antagonists separately inhibited about one-third and two-third of the total stimulation, respectively. Through alpha-AR occupancy, epinephrine provoked a significant increase of glucose release whereas no stimulation was detected in Ca2+-depleted hepatocytes. Glucose release was strongly elevated by both ionomycin and dibutyryl cAMP. These results represent the first direct evidence that alpha-AR transduction pathway is involved in epinephrine-induced glucose release from fish hepatocytes. 相似文献
447.
448.
449.
G Sansone U Gallone L Rossi G Biondi 《Bollettino della Società italiana di biologia sperimentale》1979,55(19):2031-2035
The authors have investigated on the anionics detergents rate inside the Mytilus Galloprovincialis, used as animal-monitor of the environment state of a certain part of the Gulf of Naples. The data concerning 14 zones in which were drown mussels cultivated in the Gulf of Naples resumed in a specific list, shown an high concentration of above detergents. 相似文献
450.
G Biondi M Fuciarelli O Rickards G Spedini L Terrenato 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》1983,41(1):47-52
In this paper phenotype and gene frequencies of ten genetic markers (AK, AP, EsD, 6-PGD, PGM1, PGM2, Hb, Alb, Cp and Hp) of the four Albanian communities (Campomarino, Montecilfone, Portocannone and Ururi) living in Molise are reported. The gene frequencies show a high variability. The heterogeneity analysis among these villages could demonstrate significant differences between Campomarino and Montecilfone and between Campomarino and Ururi. It is interesting to note that the demographic analysis has shown the highest rate of immigration and the lowest percentages of endogamy, Albanian surnames and Albanian-speaking individuals in Campomarino. Against that Montecilfone and Ururi are showing opposite values for the same parameters. The genetic data are also indicating some differences between these Albanian communities and the Italian population. A comparison with the present population of Albany is not possible because of the lack of data. 相似文献