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51.
Five disulfide bridges stabilize a hevein-type antimicrobial peptide from the bark of spindle tree (Euonymus europaeus L.) 总被引:4,自引:0,他引:4
Van den Bergh KP Proost P Van Damme J Coosemans J Van Damme EJ Peumans WJ 《FEBS letters》2002,530(1-3):181-185
A small 45 amino acid residue antifungal polypeptide was isolated from the bark of spindle tree (Euonymus europaeus L.). Though the primary structure of this so-called E. europaeus chitin-binding protein or Ee-CBP is highly similar to the hevein domain, it distinguishes itself from most previously identified hevein-type antimicrobial peptides (AMP) by the presence of two extra cysteine residues that form an extra disulfide bond. Due to these five disulfide bonds Ee-CBP is a remarkably stable protein. Agar diffusion and microtiterplate assays demonstrated that Ee-CBP is a potent antimicrobial protein. IC50-values as low as 1 μg/ml were observed for the fungus Botrytis cinerea. Comparative assays further demonstrated that Ee-CBP is a stronger inhibitor of fungal growth than Ac-AMP2 from Amaranthus caudatus seeds, which is considered one of the most potent antifungal hevein-type plant proteins. 相似文献
52.
Gontier E Cario-André M Lepreux S Vergnes P Bizik J Surlève-Bazeille JE Taïeb A 《Pigment cell research / sponsored by the European Society for Pigment Cell Research and the International Pigment Cell Society》2002,15(1):41-48
Congenital nevi are composed of pigment cells bearing common features with melanocytes but showing altered differentiation which leads to nesting and dermal involvement. Using a dead de-epidermized dermis seeded with a combination of keratinocytes and various sources of pigment cells (normal melanocytes, dermal nevus cells from congenital nevi, Bowes melanoma cells), we have studied the formation of nests and the dermal migration of pigment cells together with their secretion profiles of matrix metalloproteinases (MMP). Dermal fibroblasts were also used as control cells in epidermal reconstructs. Besides their morphologic features, the absence of pigment donation to keratinocytes was the major characteristic of dermal nevus cells. A positive correlation was established between the increasing percentage of seeded nevus cells and the patchy pigmentation of reconstructs, as well as the clustering of cells in junctional nests. However, the presence of nevus cells in the dermis of reconstructs was never detected, whereas melanoma cells and dermal fibroblasts could invade the dermis during the time span of the experiments. MMP9 was never expressed in congenital dermal nevus cells but pro-MMP2 was constitutively expressed by all strains of congenital nevus cells and dermal fibroblasts. Melanocytes produced comparable amounts of both pro-MMP2 and pro-MMP9, and Bowes melanoma cells secreted a marginal level of pro-MMP2. In view of their three-dimensional behaviour and secretion of MMPs, we propose that dermal congenital nevus cells correspond to an intermediate status of differentiation between normal melanocytes and melanoma cells. Activation of MMPs by a cofactor or the activation of another signalling pathway seems necessary to induce the dermal passage of nevus cells. 相似文献
53.
Torfs H Poels J Detheux M Dupriez V Van Loy T Vercammen L Vassart G Parmentier M Vanden Broeck J 《Invertebrate neuroscience : IN》2002,4(3):119-124
The bioluminescent Ca2+-sensitive reporter protein, aequorin, was employed to develop an insect cell-based functional assay system for monitoring
receptor-mediated changes of intracellular Ca2
+-concentrations. Drosophila Schneider 2 (S2) cells were genetically engineered to stably express both apoaequorin and the insect tachykinin-related peptide
receptor, STKR. Lom-TK III, an STKR agonist, was shown to elicit concentration-dependent bioluminescent responses in these S2-STKR-Aeq cells.
The EC50 value for the calcium effect detected by means of aequorin appeared to be nearly identical to the one that was measured by
means of Fura-2, a fluorescent Ca2
+-indicator. In addition, this aequorin-based method was also utilised to study receptor antagonists. Experimental analysis
of the effects exerted by spantide I, II and III, three potent substance P antagonists, on Lom-TK III-stimulated S2-STKR-Aeq cells showed that these compounds antagonise STKR-mediated responses in a concentration-dependent
manner. The rank order of inhibitory potencies was spantide III > spantide II > spantide I.
Revised version received: 12 September 2001
Electronic Publication 相似文献
54.
Cinclotaenia sp., described originally by Georgiev & Genov (1985) from the dipper Cinclus cinclus (L.) in Bulgaria, has recently been identified from the same host in the Carpathian Mountains in the Slovak Republic. This tapeworm is considered to be a new species, which is named C. georgievi n. sp. It is characterised by: a scolex armed with 23-27 (predominantly 24-26) hooks in two rows; hooks 30.5-36 microm long, with a blade 10-13.5 microm long and resembling in shape the diorchoid hooks of hymenolepidids; irregularly alternating genital pores with simple genital atria; a slightly conical cirrus armed by small spines of up to 3 microm in length; 24-51 testes posterior to a bi-alate, branched ovary; a gravid uterus filled with egg packets; and eggs with filaments. C. georgievi n. sp. differs from the closely-related C. tarnogradskii (Dinnik, 1927) in the slightly higher number of rostellar hooks, which have longer blades, and a larger cirrus. 相似文献
55.
Fluorescence binding measurements and molecular modeling were employed to study the interaction of hypericin (Hyp) with human (HSA), rat (RSA), and bovine (BSA) serum albumins. Fluorescence emission data show the solubility of Hyp increasing in the order BSA, HSA, and RSA. Molecular modeling was used to construct the detailed structural models of the complexes and to explain the differences in the binding properties of Hyp. It was shown that the structures of Hyp/HSA and Hyp/RSA complexes are more similar and in some aspects different from those found for the Hyp/BSA complex. The role of the amino acid sequence in the IIA subdomains of HSA, RSA, and BSA is discussed to explain the observed differences. 相似文献
56.
Miederer M Seidl C Beyer GJ Charlton DE Vranjes-Duric S Comor JJ Huber R Nikula T Apostolidis C Schuhmacher C Becker KF Senekowitsch-Schmidtke R 《Radiation research》2003,159(5):612-620
We investigated the effects of the alpha-particle emitters (149)Tb and (213)Bi coupled to a tumor-specific antibody targeting the mutated delta 9 E-cadherin (d9 E-Cad) on single cells and cell pellets. The d9 mutation of the adhesion molecule E-cadherin is found in 10% of diffuse-type gastric cancers and is not expressed in normal tissue. Human breast cancer cells (MDA-MB-435S) transfected with d9 E-Cad or the wild-type E-cadherin gene were used to study the effects of anti-d9 E-Cad MAb coupled to (149)Tb and (213)Bi ((149)Tb-d9 MAb and (213)Bi-d9 MAb). The density of binding sites determined on transfected MDA tumor cells by Scatchard analysis and flow cytometry varied from 4 x 10(4) to 6 x 10(4) antigens per cell. Internalization of radioimmunoconjugates by cells expressing d9 E-Cad was less than 10% of bound antibody within 240 min. The effect of the radioimmunoconjugates on cell suspensions and cell pellets was quantified by [(3)H]thymidine incorporation, and the dose to the cell nuclei was determined using microdosimetric calculations. (149)Tb and (213)Bi immunoconjugates affected cells in suspension similarly. Significant differences in the proliferation capacity of d9 E-cadherin- and wild-type E-cadherin-expressing cells were observed at activity concentrations around 185 kBq/ml, corresponding to antibody concentrations between 200 ng/ml and 1000 ng/ml. Proliferation after incubation with (213)Bi-d9 MAb was 50% greater in pelleted wild-type E-Cad-expressing cells compared to wild-type E-Cad cells in suspension. In contrast, the proliferation of pelleted d9 E-Cad cells was similar to that of d9 E-Cad cells in suspension. For (149)Tb-d9 MAb, no significant difference was found between pelleted cells and cells in suspension for low activity concentrations. However, at high activity concentrations, (149)Tb-d9 MAb had only a small effect on pelleted cells. These in vitro studies demonstrate different effects of (149)Tb and (213)Bi conjugated to a tumor-specific antibody toward single cells and tumor cell pellets. Microdosimetric simulation of single cell survival after alpha-particle irradiation modeled the experimental results with reasonable accuracy. 相似文献
57.
Ropers HH Hoeltzenbein M Kalscheuer V Yntema H Hamel B Fryns JP Chelly J Partington M Gecz J Moraine C 《Trends in genetics : TIG》2003,19(6):316-320
Analysis of linkage intervals from 125 unrelated families with nonsyndromic X-linked mental retardation (NS-XLMR) has revealed that the respective gene defects are conspicuously clustered in defined regions of the human X-chromosome, with approximately 30% of all mutations being located on the proximal Xp. In 83% of these families, underlying gene defects are not yet known. Our observations should speed up the search for mutations that are still missing and pave the way for the molecular diagnosis of this common disorder. 相似文献
58.
J. Štěpánek Jozef Kowalewski J. Lang Peter Mojzeš 《Journal of biological inorganic chemistry》1998,3(5):543-556
The interaction of Ni(II) ions with adenine mononucleotides (5′-AMP, 3′-AMP, 2′-AMP, 2′,3′-cAMP, 3′,5′-cAMP) was studied
in aqueous solution using Raman spectroscopy and 13C and 31P NMR paramagnetic relaxation measurements. Macrochelate structures were observed to form for all non-cyclic AMPs, with increasing
stability in the series: 3′-AMP < 2′-AMP < 5′-AMP. N7 of adenine was found to be the key site of the Ni(II)-adenine interaction
for all non-cyclic AMPs. For 2′-AMP, an alternative binding to the pyrimidine ring may also exist. The dependence of Raman
spectra on AMP and Ni(II) concentration confirmed the existence of a stable 1 : 2 Ni(II)-(5′-AMP) complex, besides the 1 : 1
complexes. In this complex, the adenine moieties of both 5′-AMP molecules are situated close to Ni(II), and their relative
orientations with respect to the cation are very similar. The paramagnetic relaxation enhancements of the carbons indicate
that the nickel ion is not located in the plane of the adenine units, but that the line connecting Ni(II) and N7 deviates
strongly from the adenine planes. Phosphates are outer-sphere coordinated by the cation. Findings from both methods have led
us to propose possible global architectures of the complex.
Received: 26 June 1998 / Accepted: 22 July 1998 相似文献
59.
Sanne Stegen Inge Everaert Louise Deldicque Silvia Vallova Barbora de Courten Barbara Ukropcova Jozef Ukropec Wim Derave 《PloS one》2015,10(3)
Objective
Muscle carnosine and its methylated form anserine are histidine-containing dipeptides. Both dipeptides have the ability to quench reactive carbonyl species and previous studies have shown that endogenous tissue levels are decreased in chronic diseases, such as diabetes.Design and Methods
Rodent study: Skeletal muscles of rats and mice were collected from 4 different diet-intervention studies, aiming to induce various degrees of glucose intolerance: 45% high-fat feeding (male rats), 60% high-fat feeding (male rats), cafeteria feeding (male rats), 70% high-fat feeding (female mice). Body weight, glucose-tolerance and muscle histidine-containing dipeptides were assessed. Human study: Muscle biopsies were taken from m. vastus lateralis in 35 males (9 lean, 8 obese, 9 prediabetic and 9 newly diagnosed type 2 diabetic patients) and muscle carnosine and gene expression of muscle fiber type markers were measured.Results
Diet interventions in rodents (cafeteria and 70% high-fat feeding) induced increases in body weight, glucose intolerance and levels of histidine-containing dipeptides in muscle. In humans, obese, prediabetic and diabetic men had increased muscle carnosine content compared to the lean (+21% (p>0.1), +30% (p<0.05) and +39% (p<0.05), respectively). The gene expression of fast-oxidative type 2A myosin heavy chain was increased in the prediabetic (1.8-fold, p<0.05) and tended to increase in the diabetic men (1.6-fold, p = 0.07), compared to healthy lean subjects.Conclusion
Muscle histidine-containing dipeptides increases with progressive glucose intolerance, in male individuals (cross-sectional). In addition, high-fat diet-induced glucose intolerance was associated with increased muscle histidine-containing dipeptides in female mice (interventional). Increased muscle carnosine content might reflect fiber type composition and/or act as a compensatory mechanism aimed at preventing cell damage in states of impaired glucose tolerance. 相似文献60.