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51.
Dioxins invade the body mainly through the diet, and produce toxicity through the transformation of aryl hydrocarbon receptor (AhR). An inhibitor of the transformation should therefore protect against the toxicity and ideally be part of the diet. We examined flavonoids ubiquitously expressed in plant foods as one of the best candidates, and found that the subclasses flavones and flavonols suppressed antagonistically the transformation of AhR induced by 1 nM of 2,3,7,8-tetrachlorodibenzo-p-dioxin, without exhibiting agonistic effects that transform AhR. The antagonistic IC(50) values ranged from 0.14 to 10 microM, close to the physiological levels in human. 相似文献
52.
Hordeins, the natural substrates of barley (Hordeum vulgare) cysteine endoproteases (EPs), were isolated as protein bodies and degraded by purified EP-B from green barley malt. Cleavage specificity was determined by synthesizing internally quenched, fluorogenic tetrapeptide substrates of the general formula 2-aminobenzoyl-P(2)-P(1)-P(1)'-P(2)' 1-tyrosine(NO(2))-aspartate. The barley EPs preferred neutral amino acids with large aliphatic and nonpolar (leucine, valine, isoleucine, and methionine) or aromatic (phenylalanine, tyrosine, and tryptophan) side chains at P(2), and showed less specificity at P(1), although asparagine, aspartate, valine, and isoleucine were particularly unfavorable. Peptides with proline at P(1) or P(1)' were extremely poor substrates. Cleavage sites with EP-A and EP-B preferred substrate sequences are found in hordeins, their natural substrates. The substrate specificity of EP-B with synthetic peptides was used successfully to predict the cleavage sites in the C-terminal extension of barley beta-amylase. When all of the primary cleavage sites in C hordein, which occur mainly in the N- and C-terminal domains, were removed by site-directed mutagenesis, the resulting protein was degraded 112 times more slowly than wild-type C hordein. We suggest that removal of the C hordein terminal domains is necessary for unfolding of the beta-reverse turn helix of the central repeat domain, which then becomes more susceptible to proteolytic attack by EP-B. 相似文献
53.
Joanna Malicka Małgorzata Groth Cezary Czaplewski Regina Kasprzykowska Adam Liwo Leszek Łankiewicz Wieslaw Wiczk 《International journal of peptide research and therapeutics》1998,5(5-6):445-447
Summary The probable conformations of two cyclic enkephalin analogs, DNS-cyclo[d-Dab-Gly-Trp-Leu] (I) and DNS-cyclo[d-Dab-Gly-Trp-d-Leu] (II) (DNS=dansyl), were determined by combining the results of NOE, vicinal coupling constant and fluorescence energy transfer
measurements with theoretical calculations. The common feature of the conformations for both peptides is the presence of a
β-turn at residues 2 and 3. 相似文献
54.
55.
Kasprzak A Malkowski W Helak-Łapaj C Seraszek A Kaczmarek E Adamek A Zabel M 《Folia histochemica et cytobiologica / Polish Academy of Sciences, Polish Histochemical and Cytochemical Society》2010,48(4):646-657
The study aimed at examination of tissue expression of polysaccharides and secretory mucin 5AC (MUC5AC) in young patients (up to 25 years of age) with a symptomatic gallstones. For comparison, patients most frequently subjected to cholecystectomy were studied, i.e. patients of approximately 50 years of age with the same diagnosis. In quantitative studies on tissue expression of both mucus components, the modern technique of spatial visualization was applied for the first time. Application of the technique permitted to demonstrate significant positive relationships between expression of glycoproteins (immunocytochemical ABC technique for detection of MUC5AC) and expression of sugar components in mucus (PAS technique) and to confirm suitability of the technique for quantitative appraisal of both histochemical and immunocytochemical reactions. An even higher expression of polysaccharides in the entire mucosa and of MUC5AC was detected in gallbladder epithelium of 50-year-old patients, as compared to young patients with symptomatic gallstones. In the young patients, expression of polysaccharides correlated with inflammatory activity (grading), width of gallbladder wall and PLT level in peripheral blood. A significantly higher expression of polysaccharides in gallbladder epithelium was demonstrated in young patients admitted in the emergency mode to the hospital. These correlations in young patients may suggest a role of both mucus components in pathogenesis of cholelithiasis in this age group. A quantitative appraisal of mucus component expression in the two parts of gallbladder mucosa (epithelium vs. entire mucosa) using spatial visualization technique permitted to more accurately compare production of glycoproteins and of polysaccharides in patients with cholelithiasis and to demonstrate additional correlations of a potential clinical significance. 相似文献
56.
Mariola Kuczer Katarzyna Dziubasik Anna Midak‐Siewirska Renata Zahorska Mirosław Łuczak Danuta Konopińska 《Journal of peptide science》2010,16(4):186-189
The subject of these studies was synthesis and determination of biological properties of a series of insect peptides, such as alloferon, Any‐GS and their analogues. The synthesis of 14 peptides was performed by the solid‐phase method. Biological effect of these peptides was evaluated by the antiviral test against Human Herpes Virus type 1 (HHV‐1) in vitro using a Vero cell line. It was found that the investigated peptides inhibit the replication of HHV‐1 in Vero cells. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
57.
Joanna Łaźniewska Violetta K. Macioszek Christopher B. Lawrence Andrzej K. Kononowicz 《Acta Physiologiae Plantarum》2010,32(1):1-10
Necrotrophic fungi, being the largest class of fungal plant pathogens, pose a serious economic problem to crop production. They are the cause of heavy losses in agriculture worldwide. Understanding the process of plant infection by necrotrophic fungi, including subtle interaction networks connecting such evolutionarily distinct organisms has recently been given high research priority. Such studies are now possible mainly because of the utility of the model plant Arabidopsis thaliana. A. thaliana has a sequenced genome and thousands of mutants available, allowing investigation of virtually all aspects of plant pathogenesis. This review focuses on morphological and molecular changes in A. thaliana, which occur during response to infection by necrotrophic fungi. These responses in relation to resistance and susceptibility of the plant will be discussed. 相似文献
58.
Łukasz J Łuczaj 《Journal of ethnobiology and ethnomedicine》2010,6(1):1-16
In Italy, malaria was an endemic disease that was eradicated by the mid-20th century. This paper evaluates the prophylactic and therapeutic remedies used by folk medicine to cure malaria in Calabria (southern Italy). The data has been collected by analysing works of physicians, ethnographers, folklorists and specialists of the study of Calabrian history between the end of the 19th century and the 20th century. The data collected have allowed us to describe the most common cures used by the Calabrian people to treat malaria and the most evident symptoms of this disease, such as intermittent fever, hepato-spleenomegaly, asthenia and dropsy. This approach uncovered a heterogeneous corpus of empirical, magical and religious remedies, which the authors have investigated as evidences of past "expert medicine" and to verify their real effectiveness in the treatment of malaria. 相似文献
59.
BARBARA ŁOTOCKA EWA OSIŃSKA 《Botanical journal of the Linnean Society. Linnean Society of London》2010,163(1):70-86
The anatomy and ultrastructure of internodes, leaves and petals were compared in Hypericum elegans, H. inodorum, H. olympicum, H. forrestii and two genotypes of H. perforatum. Internode anatomy was variable between species with respect to the structure of the cortical and pith parenchyma, including the presence of secretory reservoirs. Also, the secondary growth was more extensive in shrubs, i.e. H. inodorum and H. forrestii. In leaves, phloem secretory reservoirs were formed in all species, mesophyll secretory reservoirs were absent only in H. elegans and internal nodules were present only in H. elegans and H. perforatum. The petals differed between species in the mesophyll structure and the occurrence and location of secretory structures. The phloem secretory reservoirs lacked sheaths, whereas these were distinct in the mesophyll reservoirs. Other ultrastructural traits of the reservoirs were similar in all the species studied, with the exception of the leucoplast ultrastructure. In internal nodules, the inner cells vs. sheath cells differed in the number of vesicles and other membranous structures and plastid ultrastructure. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 70–86. 相似文献
60.
CLAUDIA HEMP KJETIL LYSNE VOJE KLAUS‐GERHARD HELLER ELŻBIETA WARCHAŁOWSKA‐ŚLIWA ANDREAS HEMP 《Zoological Journal of the Linnean Society》2010,158(1):66-82
A new genus, Altihoratosphaga, is erected for species formerly assigned to Horatosphaga Schaum, 1853, and a new species is described. Four species are included in Altihoratosphaga: Altihoratosphaga nomima (Karsch, 1896), Altihoratosphaga montivaga ( Sjöstedt, 1909 ), Altihoratosphaga nou (Hemp, 2007) and Altihoratosphaga hanangensis sp. nov. All four species are restricted to Tanzanian localities, and, except for A. nomima, for which no ecological data are available, are confined to montane forest habitats. Data on ecology, acoustics, chromosomes, and molecular relationships are provided, as well as a key to Altihoratosphaga species. The present‐day distribution of Altihoratosphaga species suggests former migration events at times when wetter and colder climatic fluctuations favoured connections between montane forest communities, which today are isolated, enabling flightless taxa such as Altihoratosphaga and Monticolaria to spread. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 66–82. 相似文献