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51.
The conformational equilibrium of aminosuccinyl peptides between extended conformations and an intramolecularly hydrogen bonded type II′ β-turn conformation has been studied on the peptide Boc-L -Asu-Gly-L -Ala-OMe (Asu = aminosuccinyl residue) by means of temperature dependence of circular dichroism spectra. Owing to the peculiar chiroptical and conformational properties of the Asu residue, this technique proved to be very useful for deriving thermodynamic data for the above folding process. The value of ΔH0 (?6.6 kJ mol?1), obtained for the peptide studied in a chloroformacetonitrile mixture, shows that the lower energy of the folded conformer is primarily due to the characteristic intramolecular hydrogen bond of the β turns. © 1995 Wiley-Liss, Inc. 相似文献
52.
Antibacterial polyphenols from olive oil mill waste waters 总被引:2,自引:0,他引:2
R. Capasso A. Evidente L. Schivo G. Orru M.A. Marcialis G. Cristinzio 《Journal of applied microbiology》1995,79(4):393-398
Olive oil vegetation waters (VW) were highly toxic to both phytopathogenic Pseudomonas syringae (Smith, Yung et al. ) pv. savastanoi (Gram-negative) and Corynebacterium michiganense (Gram-positive) and showed bactericidal activity in their original concentration (in raw form). Among the main polyphenols, present in the waste waters, methylcatechol proved to be the most toxic to Ps. savastanoi at 10−4 mol 1−1 , and also demonstrated bactericidal activity, while on Coryne. michiganense it was only slightly active; catechol and hydroxytyrosol were less active on Ps. savastanoi , but inactive on Coryne. michiganense ; tyrosol and its synthetic isomers 1,2- and 1,3-tyrosol were completely inactive on both bacteria. Among the derivatives of VW polyphenols considered, acetylcatechol and guaiacol were selectively toxic for Ps. savastanoi , while o -quinone was strongly toxic for both bacteria. The minor carboxylic polyphenols of VW at 10−4 mol 1−1 were all inactive on the bacteria. VW, catechol, 4-methylcatechol and the less abundant carboxylic polyphenols proved to be toxic on Hep2 human cells. Finally the possibility of using the active polyphenols in agriculture in an integrated pest management program for the protection of the olive plant is discussed. 相似文献
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Sylvia Miescher Magali Schreyer Catherine Barras Patrizio Capasso Vladimir von Fliedner 《Cancer immunology, immunotherapy : CII》1990,32(2):81-87
Summary Evidence from the mouse system has suggested that T lymphocytes accumulating in non-lymphoid tissue, in particular epithelia, may preferentially express the T cell receptor (TCR) . In this study, we characterize the T cell receptor or phenotype of lymphocytes infiltrating human tumors of epithelial origin using monoclonal antibodies (mAb) for immunohistology and flow cytometry on cells extracted by enzyme digestion. This report shows that the majority of CD3+ tumor-infiltrating lymphocytes are TCR + but a small percentage of TCR can be clearly defined scattered throughout the tumor tissue with apparently no microanatomical selection. So far there has been little evidence for an accumulation of activated T cells in human tumor tissues as defined by mAb against molecules appearing transiently during the acute phase of activation. Now mAb are available that can identify primed or memory T cells such as mAb UCHL-1 recognizing the CD45RO antigen. Here we show that CD3+ tumor-infiltrating lymphocytes have a statistically significant accumulation of primed T cells, as compared to the autologous peripheral blood lymphocytes, suggesting their immune stimulation by tumor cells. 相似文献
56.
Three further cytochalasins fromPhoma exigua var. heteromorpha, grown on wheat, were isolated and characterized by spectroscopic methods and by chemical correlation with cytochalasin B. They were identified as cytochalasin T, a new 24-oxa[14]cytochalasan, cytochalasin F and 7-O-acetylcytochalasin B, both isolated for the first time from this fungus. Cytochalasin F showed significant activity in the brine shrimp assay and on tomato seedling growth. 相似文献
57.
Cytoskeleton and adhesion patterns of cultured chick embryo chondrocytes during cell spreading and Rous sarcoma virus transformation 总被引:5,自引:0,他引:5
Pier Carlo Marchisio Olga Capasso Lucio Nitsch Ranieri Cancedda Elisa Gionti 《Experimental cell research》1984,151(2):332-343
The cytoskeleton and the adhesion complex of chick embryo chondrocytes maintained in vitro have been studied by fluorescence and interference reflection microscopy during the process of cell spreading. The pattern of actin-containing microfilaments and the distribution of vinculin speckles on adhesion plaques have been found to change as a function of the culture time. Newly plated chondrocytes adhere to the substratum mostly around a peripheral ring-like region and show a complex tridimensional array of microfilaments. When chondrocytes flatten, they develop stress fibres and show a diffuse system of vinculin-containing adhesion plaques scattered over the entire ventral side of the cells. Upon infection with Rous sarcoma virus (RSV) chondrocytes display one or more actin-containing ruffles located on the dorsal side similar to the 'actin flowers' earlier described in other cell types. These structures have been found to accumulate vinculin too. In chondrocytes infected with two td-ts mutants of RSV, 'actin flowers' have been found to persist at the restrictive temperature. At this temperature, however, in the majority of cells, stress fibres and adhesion plaques reappear. 相似文献
58.
DNA-binding of water-soluble furocoumarins: a thermodynamic and conformational approach to understanding different biological effects.
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The interaction of two water-soluble furocoumarins, 8-(omega-diethyl aminopropyloxy)psoralen hydrochloride (I) and its 5-isomer (II), with DNA has been investigated by spectroscopic, equilibrium dialysis, hydrodynamic and chiroptical techniques. Both compounds intercalate into the polynucleotide double helix. From the dependence of the binding on ionic strength, ion release and binding free energy corrected for counterion release have been quantitatively estimated. It is shown that the differences in DNA-affinity observed for compounds I and II arise primarily from non electrostatic contributions. The binding process is exothermic, with slightly different van't Hoff enthalpies for the examined furocoumarins. Helix lengthening and dichroic effects indicate different intercalation geometries for the isomeric compounds. These studies allow a possible explanation for the finding that isomer I exhibits largely better DNA-photobinding properties, while isomer II is by far more effective as an antiviral agent. 相似文献
59.
The low molecular weight collagen synthesized by chick tibial chondrocytes is deposited in the extracellular matrix both in culture and in vivo. 总被引:8,自引:0,他引:8
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The low mol. wt. collagen (64 K) synthesized by chick embryo chondrocytes in culture is deposited in the extracellular matrix; its deposition is strictly dependent upon a correct hydroxylation. In vivo the 64 K collagen has been isolated from the cartilage of tibiae obtained from 17-day-old chick embryos. The turnover of this collagen in the extracellular matrix is very rapid: within a few hours it is matured into a 30-K fragment released in the medium. Also this maturation is dependent upon a correct hydroxylation of the molecule. The underhydroxylated form, synthesized in the absence of ascorbic acid or in the presence of alpha-alpha' dipyridyl, is not deposited in the extracellular matrix and is directly secreted as 64 K collagen in the culture medium. 相似文献
60.
Arman Mohammad Chowdhury Kazi Ashfak Ahmed Bari Md. Sazzadul Khan Mohammad Forhad Huq Maryam Md. Ataul Haque Md. Areeful Capasso Raffaele 《Phytochemistry Reviews》2022,21(6):1863-1886
Phytochemistry Reviews - Medicinal herbs are nature’s gift to humanity, contributing crucially to the preservation, maintenance and improvement of our health. In order to explore the... 相似文献